bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal levels of serum parathyroid hormone, calcitonin and alkaline phosphatase in relation to antler cycles in white-tailed deer
Authors: Chao Chun Chin , Brown Robert D. , Deftos Leonard J.
Published: December 2008

Abstract. Seasonal levels of serum parathyroid hormone (PTH), calcitonin (CT), and alkaline phosphatase (AP) were studied in relation to antler growth cycles in 8 male (2.5–6 years old) white-tailed deer. Feed consumption was recorded weekly, whereas body weight was recorded biweekly. Antler length was measured from the pedicle to the tip after velvet growth was initiated. Serum samples were obtained biweekly while animals were tranquilized with xylazine hydrochloride. Serum Ca was significantly (P < 0.05) elevated during the summer. Serum P was significantly (P < 0.05) elevated only during early fall. There was an increase in serum PTH during velvet initiation in April–May, but not thereafter. CT increased during the rapid antler growth period. Serum PTH levels were significantly (P < 0.05) elevated (0.628 vs 0.884 ng/ml) during post-velvet shedding and decreased (0.602 vs 0.346 ng/ml, P < 0.05) during postantler casting. Serum AP activity was highest during rapid velvet antler growth. Feed intake was lowest in early winter, but a compensatory increase was found in late winter. Feed intake peaked in May, then gradually decreased. Body weight was maximum in November and minimum in March. It is concluded that increased PTH during velvet initiation is responsible for Ca absorption and/or mobilization. Increasing PTH levels are related to final mineralization of antlers post-velvet shedding. Higher levels of serum Ca in June–July inhibit continued increase in PTH. Increased CT during rapid antler growth may have prevented excessive bone resorption.
Circulating concentrations of oxytocin during pregnancy in ewes
Authors: Schams D. , Lahlou-Kassi A.
Published: December 2008

Abstract. Oxytocin and progesterone were measured radioimmunologically during a control cycle, early pregnancy and during several time courses until term in 4 ewes of a local Maroccan breed of sheep. Oxytocin concentrations increased in a similar matter after day 3–4 of the control cycle or after mating and decreased on days 13–15 of early pregnancy about 2 days earlier than during the oestrous cycle. After days 18–19 of pregnancy oxytocin concentrations remained low until term at concentrations as observed during the non-luteal phase of the oestrous cycle. Contrary progesterone concentrations remained high throughout gestation. Maternal recognition of pregnancy seems to have only a slight effect on the secretion pattern of oxytocin for few days after day 12. The results indicate a similar unknown mechanism during the cycle and early pregnancy for the vanishing oxytocin secretion and perhaps synthesis.
Ovine (o) and human (h) corticotrophin releasing factor (CRF) in man: CRF-stimulation and CRF-immunoreactivity
Authors: Stalla G. K. , Hartwimmer Johanna , von Werder K. , Müller O. A.
Published: December 2008

Abstract. The biological activity of ovine (o) and human (h) corticotrophin releasing factor (CRF) in normal volunteers was investigated. Nine subjects received an iv bolus injection of 50, 100 and 200 μg oCRF. There was no dose-response relationship between the injected oCRF dosage and stimulated ACTH, β-endorphin, and cortisol secretion. The addition of glycine as a stabilizer to 50 and 100 μg oCRF had no effect on stimulated ACTH and cortisol secretion. When 50 and 100 μg hCRF were injected into the same subjects no significant difference compared to the oCRF induced ACTH-response was observed.

In contrast to the lacking relationship between the CRF dosage and the biological response there was a clearcut dose-response relationship between the amount of oCRF injected and CRF-immunoreactivity 15 min after injection measured with a specific oCRF radioimmunoassay. Though there was only 10% cross-reactivity with synthetic hCRF, endogenous CRF-immunoreactivity could be detected in 53 of 55 pregnant females and in placental extracts. The fact that endogenous CRF immunoreactivity in humans measured by the oCRF-system may be due to the CRF molecule could be supported by identical elution profiles of synthetic and endogenous hCRF which eluted less retarded than oCRF from the Sephadex column. Our data suggest that the already established stimulation-test with oCRF can be replaced in the future by a test using human material in an identical dosage. In addition determination of endogenous CRF seems to be feasible, particularly with the homologous human system and may be of use in evaluation of patients with pituitary adrenal diseases.
Measurement of 8-arginine-vasopressin by radioimmunoassay Development and application to urine and plasma samples using one extraction method
Authors: Glänzer Kilian , Appenheimer Marianne , Krück Friedrich , Vetter Wilhelm , Vetter Hans
Published: December 2008

Abstract. This paper describes the production and evaluation of an antiserum with high affinity (Ka = 1.9 × 1011 l/mol) and specifity to 8-arginine-vasopressin (AVP). The antiserum binds only to the intact and unchanged ring and tail of the AVP-molecule. AVP was labelled with 125I by a modification of the chloramin T method and purified by gel-filtration. We describe the development and validation of a radioimmunoassay for AVP in human plasma and urine, using only one extraction method (octa-decasilyl-treated silica microcolumns) for both biological fluids. The overall sensitivity of the assay method is 0.3 pg/ml plasma and 0.6 pg/ml urine. Mean (± sd) plasma AVP-concentration in normally hydrated females was 1.2 ± 0.6 pg/ml (median 1.2 pg/ml) and 1.7 ± 0.7 pg/ml (median 1.8 pg/ml) in males. Mean urinary AVP excretion was 73 ± 43 ng/day with ad libitum water intake and normal activity. Sex differences were not statistically significant. We also assessed the response of plasma AVP and urinary AVP-excretion to waterload and dehydration.
Vitamin D levels and trabecular bone remodelling before and after surgery for medullary thyroid carcinoma
Authors: Emmertsen K. , Melsen F. , Mosekilde L. , Lund Bi. , Lund Bj. , Sørensen O. H. , Charles P. , Møller J.
Published: December 2008

Abstract. We previously reported increased mean serum 1,25-dihydroxyvitamin D (1,25-(OH)2D) and increased trabecular bone remodelling in patients with medullary thyroid carcinoma (MCT) and hypercalcitoninaemia. In the present paper we report that serum 1,25-(OH)2D and trabecular bone remodelling decreased following surgical cure for MCT and hypercalcitoninaemia in 4 patients despite no detectable post-surgical hypoparathyroidism or hypothyroidism. The results obtained in the present small number of patients suggest that the altered vitamin D metabolism and trabecular bone remodelling in patients with MCT is caused by the hypercalcitoninaemia.
Effects of naloxone on catecholamine plasma levels in adult men. A dose-response study
Authors: Mannelli Massimo , Maggi Mario , De Feo Maria Laura , Cuomo Silvana , Delitala Giuseppe , Giusti Giorgio , Serio Mario
Published: December 2008

Abstract. To evaluate a possible role for endogenous opiates in modulating sympathetic-adrenal function in humans, we measured plasma epinephrine and norepinephrine (radioenzymatic method), blood pressure and heart rate in 8 normal men (aged 24–33 years) before and after placebo or different doses (0.4, 4.8, 10 mg) of naloxone. In 6 subjects plasma insulin and glucagon levels were also measured by radioimmunoassay after placebo and 10 mg naloxone.

Naloxone had no significant effect upon blood pressure, heart rate, plasma insulin, glucagon or norepinephrine. Placebo, 0.4 and 4.8 mg naloxone caused no significant change in peripheral levels of epinephrine while 10 mg produced an increase in epinephrine concentrations 15 min after iv injection (186 ± 23 vs 99 ± 9 pmol/l, P < 0.01).

Since naloxone did not modify plasma levels of insulin and glucagon, an indirect effect of naloxone on adrenal medullary secretion seems to be excluded.

These results are in agreement with in vitro experimental data obtained in animals and suggest that endogenous opiates also have a role in modulating adrenal medullary secretion in man.
The effect of urethane on pituitary-adrenal function of female rats
Authors: Hamstra William N. , Doray Deborah , Dunn Jon D.
Published: December 2008

Abstract. Urethane anaesthesia resulted in rapid and sustained increase in plasma corticosterone levels of adult female rats both in the (a.m.) AM and (p.m.) PM. Initial corticosterone levels of non-injected control rats showed marked AM-PM differences (i.e., 28.3 μg/dl and 52.6 μg/dl, respectively), but by 10 min post-injection, the morning corticosterone levels were increased (76.2 μg/dl) such that AM-PM differences were not observed. By 30 min post-injection, PM plasma corticosterone levels had increased significantly (88 μg/dl) but were not different from AM values for the remainder of the 2 h experiment. Saline injected controls showed the expected response to stress; plasma corticosterone levels were increased (P < 0.01) at 10 min but were back to baseline by 45 min (9.0 μg/dl). Dexamethasone (100 μg/dl). sc) markedly suppressed both AM and PM urethane-stimulated corticosterone levels. However, diurnal differences in dexamethasone suppression were noted; whereas morning plasma coticosterone levels averaged 24.8 μg/dl over the five sampling times corresponding PM values averaged 54.3 μg/dl. Plasma corticosterone levels of non-anaesthetized, hypophysectomized ACTH-primed and injected rats were not different from those similarly treated and anaesthetized with urethane and urethane-induced increases in corticosterone were not abolished by hypothalamic isolation (HI). However, plasma corticosterone levels of HI rats were less than those of shamoperated controls (i.e., 58 μg/dl and 74 μg/dl, respectively). Collectively, these data indicate that urethane evokes a sustained increase in pituitary-adrenal activity, that the increased activity is dexamethasone sensitive and that a site of action for pituitary-adrenal activation is, at least in part, at the level of the hypothalamo-hypophyseal complex.
Influence of oestrogen in high and low doses on plasma steroid concentrations in girls with tall stature and Turner syndrome
Authors: Zachmann M. , Manella B. , Eiholzer U. , Bucher H. , Prader A.
Published: December 2008

Abstract. Plasma DHA, 17-OH-progesterone, androstenedione, testosterone, cortisol, oestrone and oestradiol were determined before and on high dose oestrogen treatment (1, 3, 6 and 16 months) given to excessively tall girls to reduce future adult height. Basal values were normal: DHA 16.4 ± 0.8 nmol/l (n = 90), 17-OH-progesterone 4.9 ± 0.3 (n = 20), androstenedione 5.6 ± 0.3 (n = 25), testosterone 2.6 ± 0.3 (n = 24) and cortisol 395 ± 20 (n = 90). On treatment, DHA, 17-OH-progesterone and androstenedione decreased to a minimum of 9.3 ± 1.0 nmol/l (3 months, n = 13), 2.4 ± 0.3 (6 months, n = 7) and 2.6 ± 0.2 (6 months, n = 9), respectively, while testosterone remained unchanged, and cortisol increased to a maximum of 825 ± 99 nmol/l (16 months, n = 23). In 15 girls with XO gonadal dysgenesis, basal DHA was low (11.8 ± 1.0 nmol/l), and did not significantly change on low dose oestrogen replacement (13.3 ± 1.4). The cause of the fall in plasma concentrations of androstenedione, DHA and 17-OH-progesterone in treated tall girls is unknown, but it is speculated that it might be related to peripheral conversion in the augmented adipose tissue mass. The rise in plasma cortisol, on the other hand, is probably due to increased transcortin.
Twenty-four hour secretory pattern of prolactin in hyperprolactinaemic patients with pituitary micro- and macroadenomas
Authors: Seki Katsuyoshi , Uesato Tadashi , Kato Koichi , Shima Katsuji
Published: December 2008

Abstract. No nocturnal increase of prolactin (Prl) secretion during sleep has reportedly been discernible in most cases of hyperprolactinaemic patients with pituitary tumour. However, subjects previously evaluated, were in the majority, patients with large pituitary tumour. In the present study, 24 h secretory pattern of Prl was evaluated in 4 hyperprolactinaemic women with pituitary microadenoma and in 4 hyperprolactinaemic women with pituitary macroadenoma. Nocturnal increase of Prl secretion was observed in patients with microadenoma, but not in patients with macroadenoma. The nocturnal increase of Prl secretion in patients with microadenoma may reflect the function of the adenoma cells, and may suggest that the basic central nervous system programme governing Prl secretion in normals is qualitatively preserved in these patients. Alternatively, the nocturnal increase of Prl secretion may reflect the function of the normal lactotrophs remaining in these patients.
Long-term follow-up of five untreated acromegalic patients
Authors: Nortier J.W. R. , Croughs R.J. M. , Thijssen J. H. H. , Schwarz F.
Published: December 2008

Abstract. The present study describes the clinical, biochemical and radiological follow-up of 5 patients with acromegaly, selected from a group of 53 patients, who did not receive treatment during a follow-up period of 5–16 years. The characteristics of these patients included: 1) older age (4 cases), 2) a long history of mild symptoms and signs (4 cases), 3) absence of diabetes mellitus (5 cases), 4) relatively low plasma GH levels (3 cases).

The following observations were made during follow-up:

clinical activity remained constant in 3 patients and lessonned in 2 patients,

the lateral fossa area as calculated from a plain lateral X-ray of the skull remained constant and

plasma GH levels measured during an oral glucose tolerance test remained constant in 3 cases, decreased substantially in one case and reached low levels in another case. In this last patient a reproducible increase of plasma GH was found after oral administration of a single dose of 2.5 mg bromocriptine, suggesting complete normality of GH secretion.

It is concluded that acromegaly not necessarily progresses in all patients. The results re-emphasize the importance of taking the spontaneous course of pituitary adenomas into account when assessing the effect of various treatment protocols.
Effects of ovine corticotrophin-releasing factor and hydrocortisone on growth hormone secretion by pituitary adenoma cells of acromegaly in culture
Authors: Ishibashi M. , Hara T. , Tagusagawa Y. , Fukushima T. , Numata H. , Hori T. , Yamaji T.
Published: December 2008

Abstract. In an attempt to test the hypothesis that pituitary adenomas of acromegaly may possess altered cellular membrane receptors, the response of growth hormone (GH) secretion to ovine corticotrophin-releasing factor (CRF) in cultured adenoma cells of acromegaly was studied. In three out of seven experiments using different pituitary adenoma cells in culture, nanomolar concentrations of CRF caused a significant increase in GH release. The CRF-induced GH release was reproducible and a dose-response relationship was observed between the CRF concentrations and the amounts of GH released into the incubation media. Hydrocortisone, at a concentration of 1 μm, on the other hand, resulted in a significant decrease in GH secretion in four out of five experiments. When adenoma cells were co-incubated with CRF and 1 μm hydrocortisone, CRF-induced GH release was partially overcome. In one experiment, the inhibitory effect of hydrocortisone was reversed by coincubation with CRF, although CRF alone was ineffective in the stimulation of GH. These results suggest that CRF may stimulate GH release in some, though not all, patients with acromegaly, and that glucocorticoids may block this effect of CRF acting directly on the pituitary adenoma cells of acromegaly.
Body size parallels insulin-like growth factor I levels but not growth hormone secretory capacity
Authors: Eigenmann J. E. , Patterson D. F. , Froesch E. R.
Published: December 2008

Abstract. The relationships between body size, growth hormone (GH) secretory capacity and circulating insulinlike growth factor I (IGF I) levels were studied in genetically-determined subgroups of disparate size within one breed of dogs, the Poodle. Standard (large) Poodles exhibited six times the mean plasma IGF I concentration found in Toy Poodles. The mean IGF I level found in Standard Poodles significantly differed from the one found in Miniature and Toy Poodles (P < 0.001). The correlation between circulating IGF I levels and body size was found to be highly significant (P < 0.001; r = 0.88). All dogs secreted similar, normal amounts of GH in response to clonidine administration.

The results show that body weight is correlated with IGF I levels rather than with the GH secretory capacity, thus providing indirect evidence for IGF I as an important in vivo growth-promoting principle.
Desensitization of the pituitary gland induced in vivo by luteinizing hormone-releasing hormone (LRH) or by the LRH-analogue buserelin does not affect the autonomous secretion of luteinizing hormone and follicle stimulating hormone as observed in vitro
Authors: Schuiling G. A. , Moes H. , Koiter T. R.
Published: December 2008

Abstract. Three-weeks ovariectomized rats were sc implanted with Alzet® osmotic minipumps which released either LRH or the LRH-analogue buserelin at the rate of 250 ng/h. Control rats were implanted with a silastic 'shampump'. After explantation, 6 days later, the pituitary glands of part of these rats were exposed to the maximally active LRH concentration of 1 μg/ml for a period of 6 h. using a perifusion system. In a second group of rats explantation and perifusion was done not directly, but 5 days after cessation of the I.RH pretreatment.

After 6 days in vivo pre-treatment with LRH or with buserelin the pituitary LH and FSH stores were partially depleted, the depletion after buserelin being stronger than after LRH. The pituitary glands of the first group of rats showed rates of both maximally LRH-stimulated and unstimulated (autonomous) LH- and FSH-secretion which were strongly impaired, the impairment after buserelin being stronger than after LRH. In the group with a 5 days interval between in vivo LRH/buserelin pre-treatment and explantation the pituitary LH and FSH stores were restored to the range of pre-treatment levels. Of these pituitaries the autonomous secretion of LH and FSH as well as the maximally LRH-stimulated secretion of FSH was restored to the normal level; the maximally LRH-stimulated secretion of LH, however, remained depressed, indicating that 5 days after cessation of exposure to LRH or to buserelin, and in spite of restored pituitary LH/FSH contents, the sensitivity of the LH releasing system to LRH was still subnormal.

The results suggest that the autonomous secretion of LH and FSH as well as the LRH-stimulated secretion of FSH, but not the LRH-stimulated secretion of LH may be dependent on the content of the pituitary LH and FSH stores. Furthermore, after treatment with LRH or buserelin the autonomous secretion of LH may return to a normal level when the sensitivity of the LH releasing system to LRH is still impaired: apparently, the mechanisms underlying the autonomous and the LRH-stimulated LH secretion do not influence each other.

It is discussed that in situations in which a complete suppression of the pituitary-gonadal axis is demanded (carcinomata of the breast or the prostate; precocious puberty) desensitization of the pituitary gland with super-active LRH-analogues like buserelin alone is not sufficient, as this does not affect the autonomous secretion of LH and FSH. For total suppression of gonadal activity the pituitary gland must be completely depleted with relatively large doses of analogue.
A comparison of the bioactivity of human and bovine thyrotrophin preparations, as determined by intracellular cyclic AMP responses of cultured FRTL-5 cells and human thyroid cell monolayers
Authors: Bidey S. P. , Ryder K. , Gaines-Das R. , Marshall N.J. , Ekins R. P.
Published: December 2008

Abstract. A clonal strain of thyrotrophin (TSH)-dependent rat thyroid cells (FRTL-5) has been used to evaluate the biological activity of reference preparations of both human and bovine TSH. Using the accumulation of intracellular cyclic AMP as a response parameter, the widely used bovine TSH preparation. Armour 'Thytropar', was calibrated against the First International Standard of Thyrotrophin (pituitary TSH), bovine, for immunoassay. Log dose – log response curves were parallel, and a relative potency of 2.4 IU/unit of 'Thytropar' was obtained. Subcultures of FRTL-5 cells were more responsive to both bovine and human TSH than were human thyroid follicular cells maintained as primary monolayer cultures. Dose-response curves for cyclic AMP accumulation were parallel for a single cell type differentially incubated with human TSH (the First International Reference Preparation) and bovine TSH (Armour 'Thytropar') preparations. The relative potencies (units: IU) of bovine-human TSH were of the order of 2.0 when tested on both FRTL-5 cultures and primary human thyroid monolayers. This suggests that in the spectrum of structural differences between TSH receptors of different species, the discriminatory powers of the human and FRTL-5 cell TSH receptor are similar. Thus FRTL-5 cells form the basis of a bioassay system of considerable value in the study of human thyroid stimulators, as we demonstrate in an evaluation of two recent preparations of human TSH.
Interaction between catecholamines and prostaglandin F2α in human luteolysis
Authors: Bennegård Barbro , Dennefors Bo , Hamberger Lars
Published: December 2008

Abstract. From each of 14 women undergoing laparotomy at different stages of the luteal phase of the cycle. the corpus luteum (CL) was excised, cut into pieces and incubated for 120 min. Incubations were performed in the absence and presence of hCG and prostaglandin F2α (PGF2α). In addition, noradrenaline (NA) was added to the incubation medium of newly formed CL, and the adrenergic blocker propranolol to incubated specimens of mid-luteal phase CL.

After incubation the tissue levels of protein and cyclic AMP (cAMP) and the media concentrations of progesterone (P) were determined.

In young CL, PGF2α did not interfere with the stimulatory effect of hCG on neither cAMP nor P formation, while in CL of the mid-luteal phase PGF2α significantly counteracted the stimulatory effect of hCG on these two parameters. In the presence of propranolol, however, this antigonadotrophic effect of PGF2α in vitro was abolished. Furthermore, when NA was added to specimens of young CL, PGF2α significantly counteracted the stimulatory effect of hCG on both cAMP and P formation.

These in vitro data show that endogenous catecholamines may regulate the antigonadotrophic, 'luteolytic' effect of PGF2α in human CL.
Inhibition of folliculogenesis in the monkey following early follicular phase administration of an LRH agonist
Authors: Wilks John W.
Published: December 2008

Abstract. This study was undertaken to determine if early follicular phase administration of a synthetic luteinizing hormone releasing hormone (LRH) agonist would produce luteal phase defects in the monkey. (D-His-(im-Bzl)6,Pro9]LRH n-ethylamide was administered to groups of rhesus monkeys on days 1–3 of the menstrual cycle. Two responses were observed: a) anovulatory menstrual cycles of less than 14 days duration, and b) ovulatory menstrual cycles characterized by unusually long follicular phases. All 4 monkeys with shortened menstrual cycles had prominent increases in serum gonadotrophin and oestradiol concentrations during treatment with the LRH agonist; early menses in these animals was attributed to uterine bleeding upon oestrogen withdrawal. Serum FSH concentrations declined, serum LH concentrations were unaltered, and only 2 of 8 monkeys had elevations in serum oestradiol during ovulatory menstrual cycles. The mean interval from cessation of treatment with the LRH agonist to the next preovulatory gonadotrophin surge was 21.5 ± 3.2 days in ovulatory menstrual cycles. Corpus luteum function was normal following treatment with the LRH agonist in ovulatory cycles. The results indicate that both the long and short menstrual cycles observed following early follicular phase administration of the LRH agonist to monkeys can be attributed to a profound inhibition in follicle recruitment. [D-His(im-Bzl)6,Pro9]LRH n-ethylamide did not alter corpus luteum function in the monkey.
Effects of 1αOHD2 on bone tissue Studies of 1αOHD2 and 1αOHD3 in normal rats and in rats treated with prednisolone
Authors: Sjödén G. O.J. , Johnell O. , DeLuca H. F. , Lindgren J. U.
Published: December 2008

Abstract. Three months old male rats were fed a diet containing 0.3% calcium and 0.5% phosphate. Prednisolone was added to the diet at a dose of 1.5 mg a day and the effect of oral treatment with 0.5 μg 1αOHD2 or 0.5 μg 1αOHD3 was studied.

After 6 weeks rats given prednisolone had a lower bone mass and bone density. The serum phosphate concentration was also lower.

Rats given 1αOHD3 had an increased serum calcium concentration even when simultaneously treated with prednisolone. 1αOHD2 did not cause hypercalcaemia.

The decrease in bone density caused by prednisolone was prevented by the administration of 1αOHD2. Rats receiving 1αOHD3 together with prednisolone still exhibited a lower bone density. Furthermore, 1αOHD3 decreased bone mass in normal rats and caused a higher mean value of osteoclasts/area whereas 1αOHD2 reduced the number of osteoclasts/area.

The study indicates that 1αOHD2 is an effective vitamin D analogue with a lower tendency to cause bone resorption.
Isolation of two different pools of pituitary prolactin
Authors: Torres Alicia I. , Haggi Ernesto S. , Aoki Agustín
Published: December 2008

Abstract. Two pools of prolactin (Prl) were isolated from the pituitary gland. One readily soluble after homogenization and the other sedimented with secretory granules. In ovariectomized-oestrogen treated rats the latter represents the major Prl fraction of pituitary and can be recovered as immunoreactive Prl after extraction in 2.5 m urea. By correlation of electron microscopy, chromatography and RIA, evidence is gathered that the soluble fraction is constituted by monomeric (little) Prl and that secretory granules contain Prl in a polymerized form (big).
Prolactin and growth hormone secretion in chickens: stimulation by histamine and inhibition by gamma-aminobutyric acid
Authors: Hall T. R. , Harvey S. , Chadwick A.
Published: December 2008

Abstract. Anterior pituitary glands from chickens (Gallus domesticus) were incubated with or without single, mediobasal chicken hypothalami in medium containing histamine, alone or together with the antagonist diphenhydramine or in medium containing gamma-aminobutyric acid (GABA), alone or together with the antagonists bicuculline or picrotoxin. The release of prolactin (Prl) and growth hormone (GH) was measured by homologous radioimmunoassay.

Histamine had no direct effect on the release of either hormone but stimulated Prl (in a dose-related way) and GH release when anterior pituitary glands were co-incubated with hypothalami. Diphenhydramine also had no direct effect on Prl or GH secretion but blocked the stimulatory effect of histamine on hypothalamusinduced Prl and GH release.

When anterior pituitary glands were incubated without hypothalami, GABA, bicuculline and picrotoxin had no effect on the release of Prl or GH. However, GABA inhibited the release of both hormones in a concentration-related manner, when anterior pituitary glands were co-incubated with hypothalami. This inhibition was blocked by both bicuculline and picrotoxin.

These results suggest that histamine and GABA may be involved in controlling the secretion of Prl and GH from the avian pituitary gland, possibly by modifying the secretion of hypothalamic releasing and/or release-inhibiting hormones.
Seasonal variations of total and free thyroid hormones in healthy men: a chronobiological study
Authors: Pasquali Renato , Baraldi Giovanna , Casimirri Francesco , Mattioli Loretta , Capelli Maurizio , Melchionda Nazario , Capani Fabio , Labò Giuseppe
Published: December 2008

Abstract. The seasonal variations of iodothyronines and TSH serum concentrations were evaluated in 24 healthy subjects of both sexes. Using a 12 month cosine function, a significant circannual rhythm was found in T3, T4 and free T4 whose maximal values were found in September for T3, in August for T4 and in October for free T4. No significant seasonal variations in free T3 or TSH were found. Some circannual but not sinusoidal changes were found for reverse T3 and TBG. A positive linear correlation between T4, T3 and reverse T3 changes was observed, indicating that the sinusoidal oscillations of these hormones were in phase with each other. Relative weight was significantly lower in summer than in winter, though spontaneous caloric intake and physical activity did not change. A slight but significant correlation was found between relative weight and T4, free T4 and reverse T3 values measured during the period of study.
Pituitary-gonadal function in boys after high dose testosterone treatment for excessively tall stature
Authors: Brämswig J. H. , Nieschlag E. , Schellong G.
Published: December 2008

Abstract. One hundred excessively tall boys with a height prediction of 205.32 ± 5.28 cm (mean ± sd) were treated with 500 mg testosterone oenanthate (TE) every 14 days for a period of 14.96 ± 5.29 months. Following therapy, the hypothalamo-pituitary-gonadal axis was evaluated, using a standardized GnRH-test at median time intervals of 14 days, 6 weeks, 13 weeks, 6 months and 16 months.

Basal and stimulated LH- and FSH-values were not measurable or severely suppressed in all boys 14 days after termination of therapy. Starting at 6 weeks, normalization of pituitary-gonadal function was demonstrated in 93 boys (group 1) with follow-up periods of up to 48 months.

Six boys (group 2) developed transitory hypergonadotrophic LH- and FSH-secretory patterns for up to 11 months after the last TE-injection. Testosterone and gonadotrophins were within the normal range in all 6 boys, when prospectively re-evaluated at 12 to 27 months after termination of therapy.

During TE-administration, testicular volume was reduced in some, and in most boys did not show the normal enlargement occurring during puberty. However, return to normal testicular size was seen several months after treatment.

The data suggest that no major functional alterations of the hypothalamo-pituitary-gonadal axis occur in pubertal boys after high-dose and long-term testosterone therapy for excessively tall stature.
The influence of luteinizing hormone on the Leydig cells of cryptorchid rat testes
Authors: Wilton L.J. , de Kretser D. M.
Published: December 2008

Abstract. The influence of circulating LH levels on Leydig cells from cryptorchid adult rats was examined after ablation of the pituitary. After 2 weeks cryptorchidism, serum FSH and LH levels rose 2-fold while serum testosterone (T) remained unchanged. Leydig cells were hypertrophied and showed an increased response to in vitro hCG stimulation. Two weeks after hypophysectomy (hypox), serum hormone levels (LH, FSH and T), Leydig cell size, cytoplasm, organelle content and in vitro T production were all dramatically reduced. However, when hypophysectomy was combined with cryptorchidism (hypox/crypt), there was an increase in Leydig cell size, compared to hypophysectomy alone, in the presence of very low levels of serum FSH, LH and T. Compared to the hypophysectomised state, the mitochondria were larger and the cytoplasm contained more smooth endoplasmic reticulum. The response of the hypox/crypt testes to in vitro hCG stimulation, though significantly less than the cryptorchid testes, was significantly greater than the hypox testes. These results demonstrate that the changes observed in the Leydig cell after cryptorchidism can occur in the absence of peripheral pituitary hormones and are consistent with the hypothesis that a local feedback loop exists within the testis.
Somatomedin levels in cerebrospinal fluid from adults with pituitary disorders
Authors: Bückström Maria , Hall Kerstin , Sara Vicki
Published: December 2008

Abstract. Somatomedin levels in cerebrospinal fluid (CSF) were determined in patients with acromegaly, pituitary deficiency, prolactinoma, and Cushing's disease by radioimmunoassay (RIA) for insulin-like growth factor 1 (IGF-1) and for IGF-2 as well as a radioreceptor assay (RRA) with adult human brain plasma membranes and IGF-2 as ligand. The mean value of RIA-IGF-2 (31 ± 1.6 ng/ml) predominated over that of RIA-IGF-1 (5.8 ± 0.3 ng/ml), but 10 times higher levels were found by RRA-IGF-2. Patients with acromegaly were not found to have higher values than those with GH deficiency even after corrections were made for possible leakage across the blood-CSF barrier. No correlations were found between CSF somatomedin levels determined by different techniques and immunoreactive IGF-1 or GH in the peripheral circulation except for a positive correlation between CSF RIA-IGF-2 and serum IGF-1 in patients with acromegaly. These findings suggest that somatomedins in CSF consist primarily of IGF-2-like peptides which are derived from production within the central nervous system or pituitary gland rather than from transport across the blood-CSF barrier.
Total serum thyroxine and triiodothyronine; a comparison between Graves' disease and hyperthyroxinaemia due to thyroxine replacement
Authors: Pearce C.J. , Himsworth R. L.
Published: December 2008

Abstract. Serum concentrations of total thyroxine (T4) and total triiodothyronine (T3) were measured in a group of patients (n = 113) presenting with untreated hyperthyroidism due to Graves' disease and in subjects receiving oral T4 replacement (n = 93) in whom the total T4 concentration was supraphysiological (> 150 nmol/l). The mean total T4 concentration in the hyperthyroid group was 226 nmol/l, sd 59, range 151–420, and the mean total T3 concentration was 6.8 nmol/l, sd 2.73, range 3.1–17.5. For the group receiving T4 the mean total T4 concentration was 175 nmol/l, sd 25, range 150–258, and the mean total T3 concentration was 2.66 nmol/l, sd 0.45, range 1.7–4.2. In the hyperthyroid group a highly significant linear correlation was found between total T4 and total T3, T3 = 0.0354 T4 – 1.21, r = 0.761, P ⪡0.001, while in the patients taking T4 this correlation was less close, T3 = 0.0073 T4 + 1.39, r = 0.398, P⪡0.001. The two groups are readily distinguished by expressing total T4 as a molar ratio of total T3. In the hyperthyroid group the mean T4:T3 ratio was 35.6, sd 7.8, range 19.9–56.1, compared to the patients on T4 where the mean T4:T3 ratio was 67.0, sd 11.7, range 44.3–114 (t = 22.5, P⪡0.0001). An arbitrarily chosen value of 50 for the T4:T3 ratio affords a simple and convenient means of distinguishing the two categories: in only 3 patients with Graves' disease (2.6%) was the ratio above this, and it was below in only 5 patients (5.4%) taking T4. Where there is doubt as to the aetiology of hyperthyroxinaemia this simple operation will differentiate between hyperthyroidism caused by Graves' disease and surreptitious ingestion of T4. In other clinical situations where symptoms of hyperthyroidism are associated with a T4:T3 ratio greater than 50 the combination may suggest subacute thyroiditis or iodide-induced thyroid dysfunction.
Effects of long-term treatment with thyroxine on pituitary TSH secretion and heart action in patients with hypothyroidism
Authors: Yamauchi Keishi , Takasu Nobuyuki , Ichikawa Kazuo , Yamada Takashi , Aizawa Toru
Published: December 2008

Abstract. The effects of thyroxine (T4) treatment on pituitary thyrotroph cells and on the heart were studied in 68 female patients with hypothyroidism. During the initial 12 months of T4 treatment, relatively small doses of T4 (1.3 μg/kg) normalized serum T4, triiodothyronine (T3), TSH and lipid concentrations in mild hypothyroidism, while moderate doses of T4 (1.7–2.0 μg/kg) normalized serum T4, T3 and lipid concentrations but not serum TSH levels or the volume of sella turcica in moderate and severe hypothyroidism; however, serum TSH levels and the volume of sella turcica returned to normal with continuation of these doses of T4.

Systolic time intervals (ET/PEP) can discriminate between euthyroid and hyperthyroid states and agree well with serum TSH levels. However, ET/PEP was unequivocally elevated in about 40% of treated hypothyroid patients with normal serum T3, T4 and TSH levels which had been maintained over 48–54 months. Since the reciprocal relationship between free T4 and TSH levels was maintained in all treated patients, elevated ET/PEP with normal TSH levels indicates that the heart is more sensitive to thyroid hormones than the pituitary thyrotroph in 40% of treated hypothyroid patients.

During T4 treatment in patients with hypothyroidism, ET/PEP should be followed and T4 doses adjusted to maintain normal ET/PEP rather than normal serum TSH levels, especially in older patients in whom T4 may aggravate angina pectoris or provoke myocardial infarction.
Thyroid hormone levels in human breast cyst fluid
Authors: Angeli Alberto , Dogliotti Luigi , Agrimonti Fulvio , Faggiuolo Roberto , Cavallo Rossana , Tibo Angela
Published: December 2008

Abstract. Radioimmunoassayable levels of total and free 3,5,3'-triodothyronine (T3) and thyroxine (T4), thyroid stimulating hormone (TSH), thyroxine binding globulin (TBG) and prolactin (Prl) were measured in a series of samples of breast cyst fluid (BCF) aspirated from 73 pre-menopausal women with gross cystic disease of the breast and in coincidental blood samples. In BCF free T3 and free T4 were consistently higher than in plasma (P < 0.001) as was also total T3 in the majority of cases (P < 0.05). Total T4, TBG and Prl were much lower than in plasma (P < 0.001). TSH was roughly as in plasma. No correlation was found between plasma and BCF values. The results indicate that thyroid hormones may be accumulated in their effective form in the cyst fluid. A highly significant inverse correlation was found betwen intracystic free T3 and log (Prl). Our data, considered in relation to previous experimental evidence, suggest the possibility that thyroid hormones act at the breast level in concert with Prl. Accumulation of thyroid hormones in BCF could play a role in the development or maintenance of gross cystic disease of the breast or be a mere consequence of the cystic changes.
Demonstration and characterization of immunoreactive methionine-enkephalin, leucine-enkephalin, methionine-enkephalin-Arg6-Gly7-Leu8 and methionine-enkephalin-Arg6-Phe7 in human phaeochromocytoma
Authors: Youshimasa Takaaki , Nakao Kazuwa , Sakamoto Makoto , Suda Mitsuaki , Morii Narito , Ikeda Yoshio , Ishihara Takashi , Manno Masataka , Hamada Satoshi , Shimbo Shinichiro , Mori Toru , Yoshimi Teruya , Matsukura Shigeru , Imura Hiroo
Published: December 2008

Abstract. To elucidate whether or not human phaeochromocytoma contains methionine-enkephalin-Arg6-Gly7-Leu8 (Met-enkephalin-Arg-Gly-Leu) and methionine-enkephalin-Arg6-Phe7 (Met-enkephalin-Arg-Phe) together with methionine-enkephalin (Met-enkephalin) and leucine-enkephalin (Leu-enkephalin), all of which are known to exist in the same precursor molecule (preproenkephalin A), we examined extracts from 16 phaeochromocytomas using high performance liquid chromatography (HPLC) and gel exclusion chromatography coupled with radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Gly-Leu-like immunoreactivity (-LI) and Met-enkephalin-Arg-Phe-LI existed together with Met-enkephalin-LI and Leu-enkephalin-LI in 16 phaeochromocytomas. There was a wide variation in contents of Met-enkephalin-LI, Leu-enkephalin-LI, Met-enkephalin-Arg-Gly-Leu-LI and Met-enkephalin-Arg-Phe-LI. Significant positive correlations were observed among the contents of these four opioid peptides in 16 phaeochromocytomas. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe together with their high molecular weight forms, which existed in variable amounts. Molar ratios of the contents of these four opioid peptides determined after HPLC varies from case to case.

These results indicate the co-existence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe in human phaeochromocytomas, suggesting the preservation of amino acid sequences of these four opioid peptides even in neoplastic tissues. Evidence for some abnormalities in the posttranslational processing of preproenkephalin A to these four opioid peptides was obtained in certain phaeochromocytomas.
Effects of intrauterine instillation of antiserum to hCG during early pregnancy in mice
Authors: Joshi Narendra J. , Nandedkar Tarala D.
Published: December 2008

Abstract. Human chorionic gonadotrophin (hCG)-like activity has been reported in mouse and rabbit blastocysts. The presence of this hCG-like activity seems to be essential for nidation of the pre-implantation embryo. Binding sites for hCG were localised on day 4 mouse embryos by immunohistochemical techniques. Presence of hCG-like activity was confirmed by cytotoxicity test. The number of implantation sites was significantly reduced on day 8 of pregnancy. Prior treatment to day 4 mouse embryos with hCG antiserum, for 1 h in utero or in vitro and their subsequent transfer to uteri of synchronised pseudopregnant mice resulted in impaired implantation of embryos, compared to controls treated with normal rabbit serum (NRS). These results suggest that hCG-like activity present on the pre-implantation embryo may have a significant role in implantation of the embryo.
Cyclophenil, a non-steroidal compound with a higher central than peripheral oestrogenic activity: study of its effects on uterine growth and on some central parameters in castrated female rats
Authors: Celotti F. , Avogadri N. , Melcangi R. C. , Milani S. , Negri-Cesi P.
Published: December 2008

Abstract. The oestrogenic activity of cyclophenil, a non-steroidal compound which has structural analogies with both stilbene and triphenylethylene, has been reevaluated utilizing both central and peripheral parameters. The central parameters considered were LH, FSH, prolactin secretion and two enzymatic systems known to be oestrogen-sensitive: hypophyseal 5α-reductase and hypothalamic aromatase. The uterine growth test was used to determine oestrogenic peripheral activity.

The compound was administered at various doses in comparison with oestradiol benzoate (EB) to long-term castrated female rats.

Cyclophenil has an activity 1/8110 times that of EB on uterine growth, and 1/1660 and 1/550 times that of EB in inhibiting LH and FSH. respectively. The hypophyseal 5α-reductase(expressed as DHT formation) was inhibited 1710 times less by cyclophenil than by EB. The other parameters considered were unsuitable to provide a statistically reliable estimate of the potency ratios between the two compounds.

The data show that cyclophenil is an oestrogenic compound with peculiar characteristics. This substance is more effective in expressing its oestrogenic activity in central structures than in the peripheral ones.
Partial protection against streptozotocin-induced hyperglycaemia by superoxide dismutase linked to polyethylene glycol
Authors: Asplund kjell , Grankvist Kjell , Marklund Stefan , Täljedal Inge-Bert
Published: December 2008

Abstract. To test the possible role of superoxide radicals in the diabetogenic action of streptozotocin, blood glucose levels were measured in mice after a single high-dose (150 mg/kg body weight) or multiple low-dose (40 mg/kg for 5 days) injections of streptozotocin. Pre-treatment 6 h before streptozotocin with 250–300 mg/kg superoxide dismutase coupled to polyethylene glycol reduced the hyperglycaemic response in mice injected with a single dose of streptozotocin. The blood glucose levels after multiple low doses of streptozotocin were not affected by superoxide dismutase-polvethvlene glycol. Enzymatically inactive superoxide dismutase did not affect the development of hyperglycaemia. The results suggest that superoxide radicals may play a role in the diabetogenic action of streptozotocin injected as a high-dose single bolus.
Seasonal changes of steroid concentrations in seminal plasma of a European wild boar
Authors: Schopper D. , Gaus J. , Claus R. , Bader H.
Published: December 2008

Abstract. The influence of season on testicular steroid production as a parameter of testicular function has been studied in a wild boar. Semen was collected once weekly while it served the dummy. In seminal plasma concentrations of the following steroids were determined by radioimmunoassay: unconjugated testosterone, conjugated testosterone, unconjugated total oestrogens, conjugated total oestrogens and 5α-androst-16-en-3-one ('boar-taint steroid'). All steroids showed a clear seasonal pattern with highest concentrations in autumn and early winter and low levels from January to July. Maxima during the rutting season were 10–25 times greater than average values out of season. During a 2-month-period (mid-July until mid-September) libido was abolished and the wild boar refused to mount the dummy. These results indicate that the seasonal variation in testicular steroid production by the wild boar, regulated by photoperiod, are similar to those of the domestic boar.
Metergoline as an alternative to bromocriptine in amenorrhoea
Authors: Hicks B. H. , Finer N. , Herbert L. C.
Published: December 2008

Abstract. The results of this study offer further evidence that metergoline is a valuable alternative to bromocriptine in the suppression of excessive prolactin secretion. Forty-nine hyperprolactinaemic and 44 normoprolactinaemic women with amenorrhoea took part in a double-blind trial to compare the efficacy of metergoline 12 mg/day and bromocriptine 7.5 mg/day in restoring menstruation and ovulation. All the women had normal results on conventional tomography of the sella turcica, normal gonadotrophin levels and normal androgen levels. In the hyperprolactinaemic group, metergoline and bromocriptine were equally effective, with 84 and 75% respectively achieving menstruation, and 76 and 67% respectively achieving ovulation, within 4 months. In the normoprolactinaemic group, 47% menstruated and 40% ovulated on metergoline, against comparative figures of 36 and 21% for bromocriptine and 20 and 13% for placebo, but the differences were not statistically significant. Side effects were not a major problem.
Successful treatment with sodium valproate of a patient with Cushing's disease and gross enlargement of the pituitary
Authors: Koppeschaar Hans P. F. , Croughs Ronald J. M. , van 't Verlaat Johanna W. , Hendriks Martin J. , Arts Cor J. M. , Thijssen Jos H. H. , Schwarz Frits
Published: December 2008

Abstract. Transfrontal hypophysectomy was performed in a patient with Cushing's disease and gross enlargement of the pituitary. Despite some reduction of cortisol production active Cushing's syndrome remained due to the presence of a tumour remnant. Medical treatment with the GABA-transaminase inhibitor sodium valproate induced hypocorticism necessitating corticosteroid substitution therapy. Nine months after sodium valproate withdrawal hypercorticism was documented. Re-institution of sodium valproate treatment induced hypocorticism again.

As sodium valproate is known to induce a decrease of plasma ACTH in Nelson's syndrome, it is proposed that large tumours present at the time of diagnosis and those appearing after adrenalectomy may represent the spectrum of a single disorder. A prospective trial to study the effects of sodium valproate and other neurotransmitter modulating agents on the size and endocrine function of ACTH secreting macroadenomas is urgently needed.