bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON PHAGOCYTIC ACTIVITY AND PROLIFERATIVE CAPACITY OF RAT PERITONEAL MACROPHAGES IN CULTURE
Authors: Pernitcheva-Rostaing Eléna , Fontagné Jeanine , Adolphe Monique , Engellman Philippe , Morin Paul , Lechat Paul
Published: December 2008

Human chorionic gonadotrophic hormone (hCG) decreased phagocytosis of rat peritoneal macrophages in culture and also inhibited their capacity to be stimulated by an inflammatory exudate. Both effects were related to the concentration used. These experimental results suggest that elevated levels of hCG may play a role in the prevention of the rejection of the foetal allograft by the maternal host.
OXYTOCIN DETERMINATION BY RADIOIMMUNOASSAY IN CATTLE
Authors: Schams D. , Schmidt-Polex B. , Kruse V.
Published: December 2008

A radioimmunoassay for oxytocin in cow plasma is described. Antisera were raised in rabbits against synthetic oxytocin coupled to bovine thyroglobulin. Iodinated oxytocin free of unlabelled oxytocin and most likely also free of diiodo-oxytocin was used as radioactive tracer. The tracer showed a high degree of purity, and was stable on storage. It could be used in the assay for 2–3 months. The assay showed very little crossreactivity with vasopressin. Acetone was used for the extraction of oxytocin from plasma as well as from standards made of synthetic oxytocin in pooled cow plasma. Inhibition curves obtained with plasma collected from cows at parturition were parallel to those obtained with the oxytocin standard preparation. The mean recovery of oxytocin added to cow plasma was 106 % (sd = 14). The within-assay coefficient of variation (CV) varied from 5.2 to 10.9 %, and the between-assay CV was in the order of 13 %. The assay sensitivity was 1 pg (0.5 μU) per tube, corresponding to 3 pg/ml plasma.

Around the time of milking the plasma oxytocin profile showed a strong response to the preparation for milking, and a further effect releated to the attachment of the teat cups of the milking machine. Peak concentrations were in the range of 15–50 pg/ml. During parturition there was a peak of oxytocin (65 pg/ml) coinciding with the expulsion phase. After this peak levels decreased but remained measurably elevated until the expulsion of the placenta. The plasma disappearance curve for immunoreactive oxytocin after the infusion of 100 IU oxytocin over a period of 1 h showed two components with apparent half-lives of 7–9 and 25 min, respectively.
SERUM AND TISSUE CONCENTRATIONS OF IMMUNOREACTIVE CALCITONIN IN PATIENTS WITH BREAST TUMOURS
Authors: Jørgensen O. G. , Ekeland A. , Gautvik K. M.
Published: December 2008

In 137 patients with classified mamary carcinoma and in 31 patients with benign mammary lesions serum immunoreactive calcitonin (iCT) was measured and correlated with the pathological and anatomical diagnosis as well as with the clinical stage of the disease. Moreover, 50 carcinomas and 27 benign mammary lesions were examined for extractable iCT and compared with normal adjacent tissue. Serum iCT measurements in patients with benign mammary lesions showed that only one on a single occasion had a border line level of calcitonin (0.50 μg/l) while the rest had hormone concentrations less than 0.30 μg/l (normal range 0.05–0.5 μg/l). The patients with mammary carcinomas were classified from stage I to stage IV according to clinical and histological criteria. Serum iCT was within normal range in all patients, and no differences were found between the different stages. Many of the benign and malignant mammary tumours contained extractable iCT. Although a great variation was present in the concentration of tissue iCT within the same group of patients, the benign or malignant tumours did not contain more immunoreactive hormone than the adjacent normal tissue. The influence of anaesthesia and surgical stress on serum iCT was then tested in humans and in Wag/Rij rats. Anaesthesia in combination with surgery increased serum concentration of iCT in both humans and rats, but anaesthesia alone had no effect. In conclusion, both benign and malignant mammary tumours contained extractable iCT, but there was no difference between neoplastic tissue and the normal adjacent gland tissue. There was also no increased concentration of serum iCT in patients with mammary carcinoma, even with advanced disease. However, rats as well as humans when subjected to surgical stress, frequently demonstrated an increased concentration of serum iCT.
SEX DIFFERENCE IN THE INDUCTION OF LACTOGENIC RECEPTORS IN RAT LIVERS
Authors: Furuhashi Nobuaki , Fang Victor S.
Published: December 2008

The relationship between serum levels of growth hormone (rGH), prolactin (rPRL), lutenizing hormone (rLH), follicle-stimulating hormone (rFSH), corticosterone, oestrogen, (oestradiol-17β) and testosterone and the hepatic binding sites specific to [125I]human-prolactin (h-PRL) were investigated in normal rats, in rats bearing the GH- and PRL-secreting tumour (GH3), and in rats 14 days after tumour removal. The presence of GH3 tumour elevated serum levels of rGH and rPRL and concomitantly increased the hepatic binding of [125I] h-PRL; the male rats had a greater increase than the female rats. The increased binding was due to an increase in the specific membrane binding sites, whereas the affinity constant (Ka) was not changed. In both male and female rats, there was a significant positive correlation between serum rGH levels (P < 0.001) or serum rPRL (P < 0.02) and specific binding of [1251] h-PRL in female rats only (P < 0.02). In male rats, there was a significant negative correlation between serum testosterone levels and specific bindings of [125I]h-PRL (P < 0.05).

These results suggest that rGH and rPRL regulates the hepatic h-PRL receptors in female rats, and testosterone predominantly inhibits the induction of the hepatic lactogenic receptors in male rats.
UNUSUAL HETEROZYGOTES OF CONGENITAL ADRENAL HYPERPLASIA DUE TO 21-HYDROXYLASE DEFICIENCY CONFIRMED BY HLA TISSUE TYPING
Authors: Zachmann M. , Prader A.
Published: December 2008

In a previous publication, three relatives of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency from two families were considered to be unusual heterozygotes rather than homozygotes with mild clinical manifestations. Their heterozygosity could now be confirmed by HLA tissue typing.
OESTROGEN AND PROGESTERONE RECEPTOR CONCENTRATIONS IN HUMAN ENDOMETRIUM DURING GESTATION
Authors: Kreitmann B. , Bayard F.
Published: December 2008

The concentrations of endometrial oestrogen and progesterone receptors, both in cytosol and in nuclei, have been studied at 8–10 weeks and at 38–40 weeks of gestation. At these two periods the concentration of oestrogen receptors is comparable with the concentration observed during the late secretory phase of the menstrual cycle. At 8–10 weeks of gestation, concentration of progesterone receptors is also comparable with the concentration observed during the secretory phase of the menstrual cycle, but at term there is a significant increase (P < 0.05) and the concentration is then comparable with the concentration observed in the pre-ovulatory period of the menstrual cycle. The receptor binding sites are always predominantly found in nuclei and the increase in progesterone nuclear receptor at term suggests that in man the progesterone withdrawal is not a necessary step in the mechanism of uterine activation during parturition as it is in other species.
IN VITRO ANALYSIS OF ANTISERA TO RELAXIN
Authors: Larkin Lynn H. , Suarez-Quian Carlos A. , Fields Phillip A.
Published: December 2008

This article describes the development of an in vitro assay to quantitate the ability of antisera to inhibit the biological action of the pregnancy hormone, relaxin. The procedure employed a modification of the in vitro assay for the ability of relaxin to inhibit spontaneous uterine contractions as initially described by Kroc et al. (1959). Several antisera were tested that showed inhibition of relaxin activity. Tests of cross-reactivity demonstrated that antiserum produced against porcine relaxin effectively inhibited the activity in relaxin preparations from cows and rabbits but was much less effective in inhibiting the activity in rat relaxin preparations. Agar double-immunodiffusion studies supported the cross-reactivity studies in that cow and rabbit relaxin preparations gave reactions of identity with the porcine relaxin while the rat relaxin preparation did not produce a precipitin line with the anti-porcine relaxin antiserum.
ADRENOCORTICAL FUNCTION IN HYPOPHYSECTOMIZED DOGS WITH PAROTID GLAND TRANSPLANTS IN DIRECT CONTACT WITH THE BASAL HYPOTHALAMUS
Authors: Alvarez-Buylla Ramón , Tsutsumi Víctor
Published: December 2008

Adrenocortical activity was studied in three groups of dogs: control-normal, hypophysectomized (hypox), and dogs with a piece of parotid gland grafted into the sella turcica immediately after removal of the whole hypophysis (hypox + graft). Cortisol plasma level (Fk) was estimated by the competitive protein binding method. The mean base-line Fk for 21 normal dogs was 0.8 ± 0.1 μg/dl; for 12 hypox dogs 0.03 ± 0.01 μg/dl, and for hypox + graft dogs 0.5 ± 0.2 μg/dl. After mild or severe stresses the normal and hypox + graft dogs showed an increment in Fk; hypox dogs showed no change. Adrenal glands of hypox dogs revealed striking diminution in fasciculata and reticularis layers, whereas hypox + graft dogs approached normal. Light microscopy studies of the parotid gland graft showed signs of cellular differentiation. Groups of proliferating cells forming follicular structures were present mainly in the part of the parotid tissue closely associated to third ventricle presenting different staining affinities.
Somatomedin production by rat liver in organ culture
Authors: Binoux M. , Hossenlopp P. , Lassarre C. , Seurin D.
Published: December 2008

Organ cultures with livers from normal rats were used to investigate the production of somatomedins (SM) and the control of this activity by hormones.

Orosomucoid was used as an indicator of liver activity and measured by radioimmunoassay in the culture media. This protein was released continuously over a period of 6 days and a positive correlation was found between the concentrations of orosomucoid and total proteins. Cycloheximide and actinomycin suppressed the release of orosomucoid. Experiments using [3H]leucine incorporation indicated that the proteins released correspond to proteins synthesized de novo.

Orosomucoid release was stimulated by insulin and cortisol and inhibited by growth hormone. Both effects were dose-dependent. These results demonstrate the validity of the technique used for studying the release of export proteins synthetized by the liver.

Liver culture media significantly inhibited cartilage sulphation as estimated by [35S]sulphate incorporation in embryonic chick cartilage. Gel filtration (Sephadex G 25) and ultrafiltration experiments showed that the inhibition was caused by large molecules. Heating of the media (100°C for 20 min) reduced, but did not entirely suppress, the inhibitory effect.

The addition of GH (1 mU/ml) or insulin (0.25—1 mU/ml) to the culture dishes significantly increased the SM activity of the medium and a dose-dependent effect was observed with insulin. Cycloheximide suppressed the insulin-stimulated SM release. A combination of GH and insulin resulted in an additive effect.

These findings suggest that: 1) SM is synthesized by rat liver in organ culture; 2) insulin plays an important role in SM generation, as it itself is capable of both stimulating the release of SM and amplifying the stimulatory effect of GH.
In vitro bioassay for human chorionic gonadotrophin
Authors: Rabe T. , Hilgenfeldt U. , Merz W. E.
Published: December 2008

The adenylate cyclase stimulation (ACS) assay is a new in vitro bioassay for human chorionic gonadotrophin (hCG) which is based on the hCG-induced accumulation of cAMP in the incubation medium of decapsulated rat testes. The detection limit for hCG is 0.7 mIU/ml (P < 0.05). A linear dose-response curve on semilogarithmic plots was obtained using 0.18, 0.45, and 1.125 IU hCG/ml. The precision of the ACS assay was satisfactory (λ-value: 0.20 + 0.02, mean ± sd), n = 14). Intra-assay variation: 15% and inter-assay variation: 20%.

Medium cAMP was determined by means of a bovine adrenal protein binding assay. Sensitivity: 0.2 pmoles cAMP/ml. Range: 2 to 40 pmoles/ml. Intra-assay variations: 5% and inter-assay variation: 8%.

As pre-conditions for the ACS assay, cAMP kinetics and dose-response curves were investigated. In kinetic studies of cAMP production the lag phase between hormone addition and increase of medium cAMP is shortened with higher hCG concentration. The highest concentration of cAMP was measured after an incubation of 3 h. Thereafter the concentration declines exponentially due to a decrease of intracellular cAMP formation and pre-dominating activity of extracellular phosphodiesterase. A prolongation of cAMP half-life from 16.8 min to 218 min was obtained by the addition of theophylline (70 mm).

Pre-treatment of rats with 50 IU sc 48 and 24 h prior to in vitro tests caused a complete inhibition of cAMP response to hCG stimulation. Four weeks after this desensitization, the sensitivity of the testes had recovered to 80%.
A possible relationship between serum transferrin, growth hormone secretion and height velocity in children
Authors: Donnadieu M. , Schimpff R. M. , Garnier P. , Chaussain J. L. , Job J. C.
Published: December 2008

Since transferrin (Tf) in vitro has a growth-promoting activity and is associated with NSILA properties, the aim of this work was to study in vivo the relationships between Tf, somatomedin activity (SM), growth hormone (GH) secretion, and height velocity in children. An iv infusion of ornithine hydrochloride was given to 23 controls; the induced rise of GH was accompanied by a simultaneous fall of SM (r = −0.711, P < 0.001) and was preceded by a fall of Tf (r = −0.610, P < 0.01). In 17 obese children SM was within the normal range, when Tf levels were higher and arginineinduced GH peaks lower than in the controls, and a negative correlation was found between Tf basal levels and GH peaks (r = −0.608, P < 0.01). In 9 children with confirmed hypopituitarism the Tf levels were significantly lower than in the controls. In 14 children with confirmed or suspected hypopituitarism a single im injection of hGH (6 mg) failed to induce Tf variations over 24 h. In 39 of these children the height velocity was significantly correlated with Tf basal levels (r = 0.701, P < 0.001). These data suggest that transferrin is involved in growth regulation, and that GH secretion is related to transferrin levels by a feed-back mechanism.
Effect of acute and repeated administration of gamma aminobutyric acid (GABA) on growth hormone and prolactin secretion in man
Authors: Cavagnini F. , Invitti C. , Pinto M. , Maraschini C. , Di Landro A. , Dubini A. , Marelli A.
Published: December 2008

A single oral dose of 5 g gamma aminobutyric acid (GABA) was given to 19 subjects and serial venous blood samples were obtained before and 3 h after drug administration. A placebo was administered to 18 subjects who served as controls. GABA caused a significant elevation of plasma growth hormone levels (P < 0.001), but did not consistently alter plasma prolactin concentration since only 5 out of 15 subjects showed an increase of the hormone. Eight additional subjects were submitted to an insulin tolerance test before and after per os administration of 18 g GABA daily for 4 days. Protracted GABA treatment significantly blunted the response of growth hormone and enhanced that of prolactin to insulin hypoglycaemia (P < 0.01).

These results indicate that pharmacological doses of GABA affect growth hormone and prolactin secretion in man. The precise nature of GABA's effects as well as its mechanism of action remains to be clarified.
Serum somatomedin activity measured as sulphation factor in peripheral, hepatic and renal veins in normal mongrel dogs: Early effects of intravenous injection of growth hormone
Authors: Schimpff Rose-Marie , Donnadieu Marcel , Duval Michel , Leduc Brigitte
Published: December 2008

The aim of this work was to study the early effects of an intravenous growth hormone (GH) injection on serum somatomedin (SM) activity in samples from peripheral (PV), hepatic (HV) and renal (RV) veins in dogs: 5 dogs were given one bovine growth hormone (bGH) injection, 1 dog was given 5 different doses of human growth hormone (hGH) and 6 control dogs were given saline.

In bGH-treated dogs, a significant increase of SM activity occurred in the three vessels without difference between vessels. An early paradoxical decrease of serum somatomedin activity appeared in the dogs given more than 1.15 IU/kg. In the dog given hGH, the response of SM activity was significantly related to the hGH dose in the PV and not in the other vessels.

These data seem to indicate that other sites than the liver and the kidney are involved in the production of GH-induced serum somatomedin activity. Following GH injection as well as in basal status. the liver may be implicated in the regulation of serum somatomedin activity.
On the development of pituitary responsiveness to LRH and the characteristics of pre-ovulatory LH-surges in the rat. Effect of oestradiol benzoate
Authors: Schuiling G. A. , Zürcher A. F. , Pols-Valkhof N. , Koiter T. R.
Published: December 2008

Administration of oestradiol benzoate (OeB) on the second day of dioestrus of 5-day cyclic rats may advance ovulation by 24 h. The threshold dose of OeB necessary to achieve this effect varies with the time of administration. At 09.00 h, the 50% effective dose (ED-50) of OeB for advancing ovulation was 3.1 μg; at 17.00 h it was 31 μg. In the present study OeB was injected at either 09.00 or 17.00 h at doses about 3 times the corresponding ED-50's: 10 and 100 μg, respectively. Though both regimens of OeB administration resulted in advancement of ovulation, neither had more than a moderate effect on the development of pituitary responsiveness to LRH. In neither group could OeB-induced LH-surges be distinguished from "normal" 4-day rat-LH-surges and both differ from 5-day rat-LH-surges. It is concluded that (1) in the "Everett-model" OeB acts almost exclusively on the central nervous system; (2) the oestrogen-induced surge of LH is an all-or-none effect; and (3) there exists no relationship between the blood oestrogen concentrations and the characteristics of the induced LH-surges.
Effect of chronic intermittent immobilization stress on hypophyso-gonadal function of rats
Authors: Taché Y. , Ducharme J. R. , Charpenet G. , Haour F. , Saez J. , Collu R.
Published: December 2008

The neuroendocrine mechanisms involved in chronic stress-induced testosterone (T) suppression have been evaluated in adult male rats. In intact animals, restraint applied 6 h daily for 6 days increased plasma corticosterone, decreased significantly T and Prl, and, to a lesser degree, LH levels. In adrenalectomized (adr-x) rats exposed to the same stress regimen, plasma LH and T values were reduced, whereas Prl concentrations were significantly elevated as compared with intact stressed rats. Adrenalectomy alone did not modify basal levels of these hormones. In intact rats, chronic stress did not alter the amount of [125I]iodo-hCG specifically bound to crude testis membrane preparation, or the testicular responsiveness to hCG as measured by T levels 2 h after the injection of hCG (500 IU). In adr-x groups, a significant decrease in binding capacity of [125I]iodo-hCG and no alteration in hCG responsiveness have been observed. From these studies, it appears 1) that plasma T suppression induced by chronic restraint is not initially mediated by a direct action at the testis level as judged by the normal testicular hCG binding capacity and responsiveness to hCG, 2) the sustained endogenous release of glucocorticoid associated with chronic restraint exposure does not play an important role in the decrease of LH and T secretion but could participate in the drop of Prl induced by long-term exposure to stressors, 3) the decrease in LH secretion may be partly responsible for the suppression of T, whereas FSH (on the basis of previous observations) and Prl do not seem to exert a significant role.
Changes in plasma LRH during the normal menstrual cycle in women
Authors: Miyake A. , Kawamura Y. , Aono T. , Kurachi K.
Published: December 2008

The plasma concentrations of immunoreactive LRH, LH, FSH, oestradiol and progesterone were measured daily by a sensitive double antibody radioimmunoassay during 12 cycles of 8 normal cyclic women. The mean (± se) immunoreactive LRH levels in the follicular and luteal phase except the immunoreactive LRH peaks during normal cycles were 4.18 ± 0.38 pg/ml and 4.50 ± 0.45 pg/ml, respectively. The immunoreactive LRH peaks were observed in 11 of 12 cycles, appearing on day −4 to −1 from the LH surge in 9 cycles and on day +1 and +2 in 2 cycles. The mean value of immunoreactice LRH peaks was 42.0 ± 11.4 pg/ml with range of 12 to 154 pg/ml. The immunoreactive LRH peak lasted for one day in 10 cycles and for 4 days in one cycle. The immunoreactive LRH peaks in different cycles of the same women did not occur on the same day relative to the LH peak. The plasma immunoreactive LRH levels measured every 10 min for 40 min periods every day in normal cyclic women during the ovulatory phase showed slight, but not significant fluctuations. Plasma oestradiol levels began to increase on day −6, reaching a peak on day − 1, and were followed by peaks of LH and FSH. These data indicate that increase in serum oestradiol was followed by release of LRH from the hypothalamus and pre-ovulatory discharge of gonadotrophins from the pituitary.
Panhypopituitarism secondary to head trauma: evidence for a hypothalamic origin of the deficit
Authors: Jambart Selim , Turpin Gerard , de Gennes Jean Luc
Published: December 2008

A complete endocrinological exploration was performed in a 23 year old male patient who presented clinical signs of an acquired panhypopituitarism which appeared two months after a severe head trauma, in order to determine whether the deficit lay in the hypothalamus or in the pituitary. TSH had normal basal levels, but presented a delayed rise after TRH administration. PRL rose normally after TRH administration, but presented a blunted response to both metoclopramide and insulin tolerance test. Cortisol rose significatively after lysine vasopresssin, but failed to rise during insulin hypoglycaemia. These results are consistent with a hypothalamic defect. Extensive endocrinological data are often lacking in the few similar cases reported in the literature. Prl and TSH were usually found to have normal basal levels while other pituitary hormones were profoundly lowered. This was interpretated as a pituitary defect with some intact areas of the anterior lobe. However, this may also suggest a hypothalamic defect which could have been assessed by more discriminative tests.
Interaction of dopaminergic and antiserotoninergic drugs in the control of prolactin and LH release in normal women
Authors: Pontiroli Antonio E. , Alberetto Miriam , Pellicciotta Gabriele , e Silva Emilio De Castro , De Pasqua Anna , Girardi Anna M. , Pozza Guido
Published: December 2008

Prolactin (Prl) release, both in the experimental animal and in man, is stimulated by serotonin (5HT) and inhibited by dopamine (DA). Data also suggest that LH release in the animal is stimulated by norepinephrine and inhibited by DA. The role of 5HT in the control of LH release is less clear. It would appear to stimulate episodic LH release and to inhibit the LH surge at the pro-oestrus in animals, but the effect of 5HT on LH release has not yet been evaluated in man. In the present paper we have studied the effect of various DA-ergic drugs (DA, iv 1-dopa, po 1-dopa and bromoergocriptine) and of two anti-5HT drugs, metergoline and methysergide, on Prl and LH release in normal women. DA-ergic drugs lowered plasma Prl and LH levels; anti-5HT drugs, at doses able to lower Prl levels, did not affect basal LH release nor the inhibiting effect of iv 1-dopa on LH release. These data indicate that DA inhibits both LH and Prl release in normal women, and that 5HT stimulates Prl release but is not involved in the regulation of LH secretion. The fact that, at variance to all the DA-ergic drugs used, the two anti-5HT drugs did not vary LH release, suggests that metergoline and methysergide are devoid of DA-ergic activity in man, at least at the doses able to inhibit Prl release.
Dissociation of pituitary glycoprotein response to releasing hormones in chronic renal failure
Authors: LeRoith Derek , Danovitz Gabriel , Trestian Stefan , Spitz Irving M.
Published: December 2008

The LH, FSH and TSH response to LRH and TRH has been evaluated in patients with chronic renal failure. Basal gonadotrophins were elevated in 3 out of 6 males; one of 4 pre-menopausal females had increased basal LH. Exaggerated LH responses to LRH were noted in 4 out of 6 males and one of 4 females; FSH responses were increased in 3 of these males. One male and one female had attenuated LH and FSH responses to LRH. Both testosterone and oestradiol levels were reduced. In 5 out of 6 subjects tested both pre- and post-dialysis there was a greater LH and FSH response to LRH following dialysis. This suggests the presence of a dialysable toxin which is inhibiting the gonadotrophin response to LRH. Gonadotrophin levels remained elevated during 4 h of dialysis suggesting prolongation of the metabolic clearance rate. Despite low T3 levels, TSH response to TRH (200 μg) was only elicited in 2 of 6 cases. However, all 3 responded to 500 μg and 2 out of 3 to 1000 μg TRH, the third showing an attenuated response. TSH levels also remained persistently elevated in the responders. Dialysis however, failed to improve the relative TSH non-responsiveness to TRH.

In conclusion the data has shown that there is a dissociation in glycoprotein hormone responses to releasing hormones in uraemia. Whereas the gonadotrophs retain their responsiveness to LRH, the thyrotrophs appear to be more effected by the uraemic process and demonstrate an impaired response to TRH.
The failure of L-prolyl-L-leucylglycinamide to inhibit the release of α-melanocyte-stimulating hormone in the rat
Authors: Thody A. J. , de Vries C. H. Lever , Tilders F. J. H.
Published: December 2008

We have studied the effect of L-prolyl-L-leucylglycinamide (PLG) on the release of melanocytestimulating hormone (MSH) from the rat pituitary gland both in vitro and in vivo.

Superfusion of neurointermediate lobes with medium containing PLG or PLG-acetate (dose range 1–1000 ng/ml) did not affect the spontaneous release of MSH as determined by radioimmunoassay or by bioassay.

Also during static incubations of rat hemipituitaries, PLG (6.6–50 ng/ml) was without effect on α-MSH release.

Administration of PLG (1–250 ng iv) to intact male and female rats and rats bearing lesions in the medio-basal hypothalamus did not induce a fall in serum α-MSH levels.

It is concluded that PLG does not affect the release of α-MSH from the rat intermediate lobe. It is unlikely therefore that PLG mediates the inhibitory influence of the CNS on MSH release.
Thyroid gland function during childhood and adolescence
Authors: Parra A. , Villalpando S. , Junco E. , Urquieta B. , Alatorre S. , García-Bulnes G.
Published: December 2008

Serum thyrotrophin (TSH), thyroxine (T4), triiodothyronine (T3), thyroxine-binding globulin (TBG) and reverse T3 (rT3) were measured by radioimmunoassay in 175 girls and 187 boys aged 6.0 to 16.9 years, who were clinically healthy, and had negative serum antithyroglobulin and antimicrosomal antibodies. All the children had normal weight and height and were grouped at 12 months' intervals. In girls, TSH levels ranged between 5.3 ± 0.4 and 6.9 ± 0.5 μU/ml without significant changes with age; serum T4 decreased up to 13.9 years and rose afterwards; serum TBG was constant up to 13.9 years, decreased subsequently and rose after 15.9 years; serum T3 levels were lower after 13.0 years than previously; serum rT3 decreased between 11.0 and 11.9 years and rose thereafter; the calculated serum free T4 (FT4) and free T3 (FT3) concentrations had a significant rise from 14.0 to 15.9 years followed by a sharp decline; T3:T4, rT3:T3 and rT3:T4 ratios were constant up to 11.9 years, then a rise was seen in T3:T4 and a fall in the later ratios, followed by a drop in T3:T4 ratio and a sustained rise in rT3:T3 and rT3:T4 ratios. In boys, TSH levels were constant between 5.2 ± 0.4 and 6.6 ± 0.4 μU/ml; serum T4 decreased with increasing age; serum TBG was constant up to 13.9 years, and had a sustained fall thereafter; serum T3 was constant over the age range studied; serum rT3 levels decreased up to 13.9 years and rose thereafter; FT4 had no changes with increasing age while FT3, although constant up to 13.9 years, had a sustained rise afterwards; T3:T4 ratio did not change with age, while rT3:T3 and rT3:T4 ratios, although constant up to 13.9 years, showed a tendency toward a sustained rise thereafter. These sex-different variations in serum thyroid hormone concentrations might be related to the fact that girls mature at an earlier chronological age than boys and may represent a partial response of the body to the qualitatively and quantitatively different energy needs in girls as compared with boys, consecutive to the differences in body composition first appearing at puberty.
Interrelationships between energy metabolism and thyroid hormone metabolism during starvation in the rat
Authors: Burger A. G. , Berger M. , Wimpfheimer K. , Danforth E.
Published: December 2008

Thyroid hormone metabolism and plasma concentrations of TSH were studied after short-term hypocaloric refeeding of rats starved for 2–6 days. Carbohydrate and protein (10 kcal) refeeding after 4 days of starvation resulted in a rapid increase in serum T3 (P<0.01) and, less consistently of T4. Plasma TSH did not change. These findings were not due to changes in the metabolic clearance rates or in thyroid hormone binding proteins, as the disappearance of injected labelled T3 and T4, and the free fractions of T3 and T4, were unchanged. Increased thyroidal secretion, and for T3, increased peripheral conversion from T4 were therefore responsible for these changes. Fat refeeding had no immediate effect on plasma T4, T3 or TSH. After 6 days of starvation, refeeding of any nutrient was ineffective in altering the plasma concentrations of T3 and T4.

The intraperitoneal administration of nicotinamide (100 mg/100 g body weight) to starving animals caused an increase in blood glucose and a decrease in blood betahydroxybutyrate similar to that which followed carbohydrate refeeding; T3, however, did not increase. In spite of producing a profile of substrates in the serum similar to that found following carbohydrate refeeding, nicotinamide administration had no effect on the blood lactate/ pyruvate ratio which was increased following carbohydrate refeeding. Therefore, the cytoplasmic redox state, as reflected by the lactate/pyruvate ratio, may be closely related to the control of peripheral thyroid hormone metabolism.
Effect of ACTH on the proliferative and secretory activities of the adrenal glomerulosa
Authors: Payet N. , Lehoux J.-G. , Isler H.
Published: December 2008

The mitotic, trophic and secretory responses of the adrenal cortex to various preparations and doses of ACTH were investigated in the rat. 1-24-ACTH depot (Synacthen) elicited the highest mitotic and trophic stimulation. The mitotic stimulation occurred exclusively in the glomerulosa, the trophic stimulation occurred mainly in the fasciculata-reticularis and the functional stimulation was found in both, as indicated by the plasma aldosterone and corticosterone levels. The functional changes occurred first, the trophic changes later. Large doses of ACTH inhibited cell proliferation in the fasciculata. The trophic action consisted in an enlargement of the adrenal, to a great extent in the fasciculata-reticularis, and to a lesser extent in the glomerulosa. This enlargement was due partly to parenchymal cell hypertrophy, but also and mostly to stromal hypertrophy, especially hyperaemia. The largest dose of ACTH caused a considerable widening of the sinusoids of the fasciculata-reticularis and medulla, and possibly caused a loss of parenchymal cells in the reticularis. These effects are reminiscent of the well documented haemorrhagic conditions of the adrenals in humans.
Further studies on the inactivation of thyrotrophin releasing hormone (TRH) by enzymes in the rat hypothalamus
Authors: Griffiths E. C. , Kelly J. A. , White N. , Jeffcoate S. L.
Published: December 2008

Thyrotrophin-releasing hormone (TRH) is known to be inactivated by enzymes present in the rat hypothalamus. To make a further study of the enzymes' action on the tripeptide, synthetic TRH was incubated with two hypothalamic subcellular fractions. By using a direct radioimmunoassay for TRH, the tripeptide was shown to be rapidly degraded by both supernatant and particulate fractions, with higher enzyme activity in the particulate fraction. Of several biologically-active peptides tested, only luteinizing hormone-releasing hormone was found to inhibit TRH inactivation; bacitracin, a polypeptide antibiotic, was also effective in inhibiting inactivation. Enzyme activity was highest in the middle hypothalamic area and lowest in the posterior hypothalamic area. Thin layer chromatography of the products of enzyme cleavage revealed the formation of only deamidated TRH in the supernatant fraction and the constituent amino acids (pyroGlu, His, ProNH2) and histidylproline-diketopiperazine by the particulate fraction, suggesting the presence of an amidase in the supernatant and two peptidases in the particulate fractions. These properties of the enzymes inactivating TRH may indicate that the enzymes could be of importance in regulating the endocrine and other functions attributed to this hypothalamic regulatory hormone.
Red-cell 2,3-diphosphoglycerate in patients with hyperthyroidism
Authors: Alvarez-Sala J. L. , Urbán M. A. , Sicilia J. J. , Fdez A. J. Diaz , Mendieta F. Fdez , Espinós D.
Published: December 2008

In 21 hyperthyroid female patients studied on 29 occasions, high levels of red-cell 2,3-diphosphoglycerate (2,3-DPG) have been found (5.75 ± 0.7 mm) which, compared to a euthyroid control group (4.88 ± 0.4 mm), could not be accounted for by differences in haematocrit, haemoglobin or phosphataemia. A significant correlation was found (P < 0.05) between serum thyroid hormones and the 2,3-DPG concentration in the hyperthyroid patients. Eight of these patients were reexamined after treatment and normalization of thyroid function, showed a regression to normal 2,3-DPG values (4.81 ± 0.6 mm) which could not be attributed to variations in haematocrit, haemoglobin or phosphataemia either. We therefore deduce that the shift to the right in the haemoglobin oxygen dissociation curve observed in patients of this type may be due to an increase in the red-cell 2,3-DPG content.
Thyroid hormone levels related to energy and nitrogen balance during weight loss and regain in adult sheep
Authors: Blum J. W. , Gingins M. , Vitins P. , Bickel H.
Published: December 2008

Caloric deprivation (feeding 50 and 25% of the original maintenance requirement for 126 days), followed by overnutrition (feeding 133 and 200% of the original maintenance requirement) for 37 days, were induced in 7 adult sheep. Before and after the periods of undernutrition and after overnutrition the animals were fasted (total energy withdrawal) for 5 days. Energy- and nitrogen-balances were determined and related to concentrations of thyroxine (total: T4; free: FT4), 3,5,3′-triiodothyronine (total: T3; free: FT3) and 3,3′,5′-triiodothyronine (reverse T3,rT3).

Caloric deprivation led to decreased T3 and FT3 levels, overnutrition to increased T3 and FT3 concentrations. T3 was significantly correlated with energy- and nitrogen-balances (r = 0.73 and 0.71, respectively; P< 0.001). T4 and FT4 behave similar to T3, but correlations between T4 levels and energy- and nitrogen-balances were low. In contrast to T3, rT3 levels increased during energy withdrawal and decreased during overnutrition. After an overnutrition for months, an additional fasting for 5 days did not increase rT3 levels, however. rT3 was significantly correlated with energy- and nitrogen-balances (r = −0.50 and −0.50, respectively; P < 0.01).
Leucine assimilation in patients with diabetes mellitus
Authors: Bratusch-Marrain P. , Ferenci P. , Waldhäusl W.
Published: December 2008

To estimate leucine metabolism in patients with absolute or relative insulin deficiency, elimination of an iv leucine load (50 mg/kg) was determined in 5 insulin-dependent diabetics, in obese (n = 5) as well as in ideal weight maturity onset diabetics (n = 5). Following leucine administration a marked rise of plasma insulin levels in obese diabetics, but lack of insulin response in insulin-dependent diabetics was observed compared to healthy controls (n = 6). Elimination half-life of leucine was similar in controls (34 ± 5 min), in obese (40 ± 4 min) and in ideal weight maturity onset diabetics (37 ± 2 min), but significantly prolonged in insulin-dependent diabetics (60 ± 3 min; P < 0.01). Thus in obese diabetics elevated plasma insulin levels and near normal elimination half-life of leucine suggest peripheral insulin resistance regarding leucine assimilation. In insulin-dependent diabetics, however, it appears that insulin deficiency is associated not only with elevated plasma leucine levels, but also with delayed elimination by peripheral tissues following administration of this amino acid.
Effects of phenylbutazone on thyroid iodine metabolism in vitro
Authors: Targovnik Héctor M. , Gluzman Bernardo E. , Coleoni Aldo H. , Niepomniszcze Hugo
Published: December 2008

Several alterations of thyroid function parameters have been reported in patients treated with phenylbutazone and we have studied the effect of this drug on the intrathyroidal iodine metabolism. An inhibition of the iodide transport expressed in terms of T/M ratios was observed in bovine thyroid slices incubated with high phenylbutazone concentrations. 10−3m produced 72% inhibition whereas lower concentrations showed no significant difference as compared with controls.

Iodotyrosine synthesis was affected by 10−4m and 10−5m phenylbutazone. Formation of iodothyronine synthesis was markedly affected between 10−4m and 10−7m phenylbutazone concentrations. Thyroid peroxidase activity was measured by tyrosine-iodinase, triiodide and guaiacol assays. Soluble, pseudosolubilized and crude peroxidase preparations from bovine glands, as well as the soluble enzyme from human thyroids, have shown inhibition of tyrosine-iodinase activity when incubated with phenylbutazone in concentrations ranging from 10−3m to 10−8m, with a Ki of 4 × 10−6m for bovine thyroid peroxidase and of 6 × 10−6m for human soluble peroxidase. Formation of triiodide was affected between 10−3m and 10−8m phenylbutazone concentrations. Guaiacol peroxidation was scarcely affected by the action of the drug.

We have concluded that phenylbutazone affects the intrathyroidal iodine metabolism through the inhibition of thyroid peroxidase in concentrations which are usually present in the sera of patients treated with this drug.
Effects of D-mannoheptulose on blood glucose and alloxan sensitivity in mice
Authors: Boquist Lennart
Published: December 2008

D-mannoheptulose (MH) administration induced a decreased serum insulin concentration in fed and starved mice, and a transient hyperglycaemia in fed mice, but not in starved ones. The liver glycogen concentration was decreased in starved controls and in fed mice treated with MH. Differences in the capacity for rapid hepatic glycogenolysis may have contributed to the different blood glucose responses in fed and starved mice. The hyperglycaemia in fed mice was unaffected by pre-treatment with L-leucine, or p-hydroxymercuribenzoate (PMB), but was abolished by pre-treatment with tolbutamide, and by post-treatment with insulin. Treatment of fed mice with MH before alloxan caused a marked "initial" hyperglycaemia but no second hyperglycaemia, and thus no development of alloxan diabetes. In starved mice injected with MH before alloxan there was an inhibition of the initial hyperglycaemia, but occurrence of a "second" hyperglycaemia, suggesting an absence of protection against the development of alloxan diabetes. The data show that alloxan diabetes may develop in the absence of an "initial" hyperglycaemia and a triphase blood glucose response. The hyperglycaemic action of MH in fed mice is believed to underlie the protection against alloxan toxicity.
Effects of arginine vasotocin, oxytocin, and arginine vasopressin on steroid-induced surges of luteinizing hormone and prolactin in ovariectomized rats
Authors: Salisbury Ronald L. , Krieg Richard J. , Seibel Hugo R.
Published: December 2008

Several studies have indicated that arginine vasotocin (AVT), a nonapeptide closely related to vasopressin (ADH) and oxytocin (OT), may act as a pineal antigonadotrophic factor. The present studies were designed to investigate the effects of AVT on the luteinizing hormone (LH) and prolactin (Prl) release induced by sequential steroid priming of ovariectomized (OVX). rats. Sprague-Dawley rats were used 6–8 weeks post-OVX. After implantation of an intra-atrial bleeding catheter, animals were primed with 5 μg of oestradiol benzoate (EB) at 08.00 h on the next morning. Forty-eight hours later 1.5 mg of progesterone (P) was injected and animals were divided into groups which received either saline, AVT (1 of 4 doses), ADH, or OT. The saline or peptides were infused via the intra-atrial catheter at 10.00, 11.00, 12.00, and 13.00 h. Hourly blood sampling was performed at 11.00–18.00 h, and at 21.00 h. The 11.00, 12.00, and 13.00 h samples were taken 10 min after saline or peptide infusion. LH and Prl responses to the peptide infusions could be divided into pre-surge and surge effects. AVT caused a slight, but significant elevation of the normally low levels of LH and Prl which occurred before the onset of their surges. Only the highest dose of AVT (1.0 μg) blocked the LH surge. ADH, however, was capable of stimulating LH and Prl release during the pre-surge period and of inhibiting the LH surge. AVT at a dose of 0.5 or 1.0 μg specifically blocked the onset of the Prl surge, causing Prl to drop to its lowest level at 14.00 h - the time at which Prl levels were maximal in saline-treated animals. After this initial inhibition, however, Prl levels rebounded to show a delayed surge. OT infusion, on the other hand, caused a significant augmentation of the Prl surge. These data indicate that AVT may specifically block the onset of the Prl surge seen after sequential steroid priming of OVX rats, while OT may facilitate the Prl surge.
Some observations concerning the role of progesterone in the control of ovulation
Authors: Schuiling G. A. , Pols-Valkhof N. , Zürcher A. F.
Published: December 2008

Pre-ovulatory LH-surges in 4-day cyclic rats (4d-r) were postponed 1, 4, or 8 days by treatment with progesterone (P), or 1 day by treatment with pentobarbitone just prior to the onset of the 'critical period' on pro-oestrus. P-delayed LH-surges tend to become higher with increasing duration of the preceding anovulatory period: 1 day-delayed surges were as high as 5d-r surges (i.e. about twice as high as spontaneous 4d-r surges); 8 days-delayed surges were significantly higher. Compared with 4d-r surges the time of onset and zenith of P-delayed surges is significantly advanced.

The 1 day-pentobarbitone-delayed surges too were as high as 5d-r surges, but still timed as 4d-r surges. On no 'artificial' pro-oestrus day did the responsiveness of the pituitary differ from the 'normal' pro-oestrus responsiveness.

It is concluded that P influences the timing but not the height of pre-ovulatory LH-surges.
Prolongation of the effects of gonadotrophins and prostaglandin E2 on ovarian cyclic AMP formation by inhibitors of protein synthesis
Authors: Bergh Christina , Ahrén Kurt
Published: December 2008

The effects of LH, FSH and PGE2 on the accumulation of cyclic AMP by isolated whole ovaries from 23–24 day-old rats were studied in time-course experiments in presence and absence of two inhibitors of protein synthesis, puromycin and cycloheximide. In absence of these inhibitors ovarian cyclic AMP levels reached peak levels within 30 min for all three stimulators and returned towards pre-stimulation levels within 2–4 h. When puromycin (500 μg/ml) or cycloheximide (5 μg/ml) was present together with LH, FSH or PGE2, respectively, ovarian cyclic AMP levels did not decrease after the initial peak but remained high for the entire incubation period (4–5 h). The release of cyclic AMP to the incubation medium was also much higher when puromcyin or cycloheximide was present, illustrating that the effect of puromycin and cycloheximide was not caused by an inhibition of the cyclic AMP release. The effects of puromycin and cycloheximide were, in principle, the same when a phosphodiesterase inhibitor, 3-isobutyl-l-methylxanthine, was present. The results indicate either that there are, in the ovary, proteins with very rapid turn-over, necessary for the mechanism leading to refractoriness of the cyclic AMP system, or that the gonadotrophins and PGF2 as an early effect stimulate the production of a specific protein necessary for the development of refractoriness.
Large molecular species of chorionic gonadotrophin from human placental tissues: biosynthesis and physico-chemical properties
Authors: Maruo Takeshi , Segal Sheldon J. , Koide S. S.
Published: December 2008

Human placental tissues in the first trimester of pregnancy were maintained in organ culture and incubated with [3H]proline for 90 min at 37°C. The tissues were homogenized with a protease inhibitor in the buffered medium and separated into subcellular components. A large molecular protein which reacted with antiserum to hCG hCGα and hCGβ, and with the receptor membranes obtained from bovine corpus luteum, was detected in the microsomal component and post-microsomal supernatant fraction. This protein was purified by chromatography on Sephadex G-100, Sepharose-6B and DEAE-Sephadex A-50. The large molecular species of hCG contained high radioactivity and was immunoprecipitated with all three antisera. The purified large molecular hCG was analyzed by electrophoresis on sodium dodecyl sulphate (SDS) polyacrylamide gel. Its molecular weight was estimated to be 90000 daltons. When the large molecular hCG was treated with 8 m urea and mercaptoethanol in the presence of SDS, a major portion of the material dissociated into immunoreactive α and β subunits of rather high molecular weights compared to standard hCG subunits. Under similar conditions standard hCG dissociates completely into its subunits. The present results suggest that the large molecular species of hCG might be a complex composed of larger forms of α and β subunits. This complex might be an intermediary component in the biosynthetic pathway of hCG or a product of posttranslational modification.
Stromal 5α-reductase activity is elevated in benign prostatic hyperplasia
Authors: Wilkin R. P. , Bruchovsky N. , Shnitka T. K. , Rennie P. S. , Comeau T. L.
Published: December 2008

The activities of 5α-reductase and 3α(β)-hydroxysteroid dehydrogenase were assayed in homogenates of stroma and epithelium obtained from 3 normal, 9 hyperplastic and 2 carcinomatous human prostates. Irrespective of the normal or abnormal condition of the prostate, the localization of 5α-reductase was predominantly in stroma whereas the reductive and oxidative activities of 3α(β)-hydroxysteroid dehydrogenase were more evenly divided between stroma and epithelium. Furthermore, the mean specific activity of 5α-reductase in hyperplastic stroma at 84.6 ± 13.1 (± sem) pmol 30 min−1 mg protein−1 was almost 3 times greater (Student's t-test, P < 0.05) than the corresponding value in normal stroma, 31.6 ± 7.2 pmol mg protein−1 30 min−1. We conclude that the stroma is the primary site of conversion of testosterone to dihydrotestosterone in the human prostate owing to the prevalence in stroma of 5α-reductase, and that benign prostatic hyperplasia is characterized by an increased amount of stromal 5α-reductase activity.