bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of sex steroids on the degradation of LRH by hypothalamic homogenates
Authors: Tate Anna C. , Swift A. D. 
Published: December 2008

Abstract.
Extract of hypothalami was prepared which contained peptidase capable of degrading LRH. The degradation of LRH by this extract either alone or under the influence of oestrogens, androgens and cholesterol, when added to the extract was measured. Oestrone, oestradiol and oestriol (1 pg to 100 pg) stimulated mean peptidase activity significantly (P< 0.001) in a dose-dependent manner. Testosterone (0.1 ng to 10 ng) also caused a dose-dependent increase in degradation of LRH, the two highest doses used significantly increasing the mean activity (P < 0.001). Only the highest dose of androstenedione (10 ng) or dehydroepiandrosterone (10 ng) caused a significant increase of the mean LRH degradation (P < 0.05). Neither cholesterol nor dihydrotestosterone increased peptidase activity when added to the extract.
It is suggested that it is possible that these peptidase enzymes could occupy a role in the negative feedback of steroids on the hypothalamus.
Effects of bromocriptine-induced pregnancy on prolactin-secreting pituitary tumours
Authors: Bergh T. , Nillius S. J. , Larsson S.-G. , Wide L. 
Published: December 2008

Abstract.
Twenty-eight women with hyperprolactinaemia and amenorrhoea received bromocriptine treatment which resulted in 31 term pregnancies. Bromocriptine treatment was stopped as soon as pregnancy was established. Nineteen of the women had radiological signs of a pituitary tumour. The pregnancies were clinically un-eventful in all cases except one who developed headache. Post-partum sellar X-ray showed pregnancy-induced enlargement of the pituitary fossa in 4 of the 28 women. Regression of the radiological changes occurred in 3 of the 4 women within 2 years after the delivery. The women with abnormal sellar X-rays had no difference in the mean prolactin levels before treatment and after pregnancy and lactation while all the women with normal sellae had lower prolactin levels after pregnancy than before. Three women resumed regular spontaneous menstruations after pregnancy and lactation but only one conceived again.
Thus, serious pituitary tumour complications are rare in hyperprolactinaemic women with bromocriptine-induced pregnancies. The pregnancy does not worsen the condition. Resolution of hyperprolactinaemia after bromocriptine-induced pregnancy is an unfrequent finding.
Characterisation of the cyclic AMP response to thyrotrophin in monolayer cultures of normal human thyroid cells
Authors: Bidey Stephen P. , Marshall Nicholas J. , Ekins Roger P. 
Published: December 2008

Abstract.
The cyclic AMP response to thyrotrophin (TSH) has been investigated in cells prepared from human thyroid tissue obtained during surgery for sub-total laryngectomy, and maintained under in vitro conditions as primary monolayer cultures.
When cells were incubated with 1.0 mU TSH/ml, a maximal level of intracellular cyclic AMP was reached after 20 min of incubation in the presence of 0.5 mm 3-isobutyl-1-methyl xanthine (MIX). This level of cyclic AMP was sustained for at least 2 h. Half-maximal stimulation of cyclic AMP was produced by TSH doses of between 1 and 5 mU/ml. In a study of a series of eight groups of monolayer cultures, each derived from a single, different thyroid gland, the mean stimulation of cyclic AMP given by 50 mU TSH/ml was 37.8-fold greater than in non-stimulated cell monolayers.
Significant stimulation to 50 μU TSH/ml was observed in some monolayers and the precision of measurement of TSH was better than 15% over the TSH dose range 0.2–1.0 mU/ml. The magnitude of the cyclic AMP response to TSH was unaffected by the presence in the incubation medium of 20% (v/v) normal human serum. A cyclic AMP response to TSH was still demonstrable in cells that had been maintained for a period of 22 days in monolayer culture, although the response was reduced in comparison with that given by 4–5 day old cultures.
A new protease in hog thyroid lysosomes
Authors: Nakagawa H. , Endo Y. , Ohtaki S. 
Published: December 2008

Abstract.
A leupeptin-sensitive new protease was partially purified from hog thyroid lysosomes. The purification procedure included solubilization by hypotonic treatment of lysosomes, and Sephacryl S-300 and Sephadex G-100 gel chromatography, and the purification ratio was 10-fold from lysosomes. The pH optimum of the protease activity was around 5.5 and its molecular weight was estimated to be 22 000 by gel filtration. 2-Mercaptoethanol activated the hydrolysis of protein substrates and its effect was most pronounced in the case of thyroglobulin as substrate. Among the inhibitors used, leupeptin, antipain, toluenesulfonyl-lysine chloromethyl ketone and, to a lesser degree, chymostatin and toluenesulfonyl-phenylalanine chloromethyl ketone effectively inhibited the hydrolysis of casein by the enzyme at pH 5.5, whereas pepstatin did not inhibit the activity significantly. The enzyme activity was also inhibited by sulfhydryl inhibitors such as iodoacetamide, p-chloromercuribenzoate, and N-ethylmaleimide.
The release of iodoamino acids from thyroglobulin by the enzyme was inhibited in the same manner by the inhibitors used in the hydrolysis of casein.
The physiological role of the new protease is discussed in comparison with cathepsin B and L found in liver lysosomes.
The relation between catecholamines, glucagon and pancreatic polypeptide during hypoglycaemia in man
Authors: Järhult Johannes , Farnebo Lars-Ove , Hamberger Bertil , Holst Jens , Schwartz Thue W. 
Published: December 2008

Abstract.
The effects of insulin hypoglycaemia (0.15 IU/kg) on plasma adrenaline, noradrenaline, dopamine, glucagon and pancreatic polypeptide (PP) concentrations were investigated in 6 adrenalectomized subjects and 6 healthy controls. Both the rise in mean plasma insulin and the fall in mean blood glucose concentration were closely similar in the two groups. Mean plasma adrenaline concentration rose by about 3 nmol/l in the normal subjects, but remained unchanged in adrenalectomized subjects. Mean plasma noradrenaline concentration increased by about 2 nmol/l in both groups. Despite the large difference in adrenaline concentrations during hypoglycaemia, there was no significant difference between the responses of the endocrine pancreas of the normal and adrenalectomized subjects. Thus, mean plasma glucagon concentration rose by about 30 pmol/l and mean plasma PP concentration by about 150 pmol/l in each group. We conclude that the release of glucagon and PP during hypoglycaemia does not depend upon changes in plasma adrenaline concentration in man.
Insulin hypoglycaemia in normal and adrenalectomized subjects: comparison of metabolic parameters and endocrine counter regulation
Authors: Altorfer R. M. , Ziegler W. H. , Froesch E. R. 
Published: December 2008

Abstract.
Insulin tolerance tests were carried out in normal subjects and in adrenalectomized (ADX) patients in order to better understand the importance of counter regulatory hormones for the recovery from hypoglycaemia.
Compared to normal subjects recovery of plasma glucose and of free fatty acid levels in adrenalectomized patients is retarded. The levels of glucagon are significantly higher in ADX patients during rest than in normal subjects. As expected, epinephrine and norepinephrine levels did not increase in ADX patients and, accordingly, blood pressure did not change. Growth hormone levels were the same in both groups of subjects. Interestingly, there was no clear-cut difference with regard to subjective symptoms of hypoglycaemia.
It would appear that epinephrine is important for the rapid initial recovery from hypoglycaemia, whereas other hormones play a more important role later on.
Biomechanical changes in connective tissues induced by experimental diabetes
Authors: Andreassen T. T. , Seyer-Hansen K. , Oxlund H. 
Published: December 2008

Abstract.
The biomechanical properties of skin and aorta were studied in rats with experimental (streptozotocin) diabetes.
After 30 days of diabetes the collagen content of the skin was diminished by 30%.
By biomechanical testing collagen from diabetic rats was found to exhibit increased stiffness and strength: maximal stiffness was increased by 20% and the strain at maximum stress was decreased by 10%.
Insulin treatment prevented all changes.
No differences were found between aortic specimens from diabetic and normal rats.
Regulation of prolactin and thyrotrophin secretion during human pregnancy: effect of sulpiride and TRH administration
Authors: Ylikorkala Olavi , Kivinen Seppo , Viinikka Lasse 
Published: December 2008

Abstract.
The regulation of prolactin (Prl) and thyrotrophin (TSH) secretions during early human gestation was studied in 30 healthy women. Twelve women were treated with oral sulpiride, 150 mg daily for two weeks, and the Prl and TSH responses to 220 μg of iv thyrotrophin-releasing hormone (TRH) were measured before and at the end of sulpiride administration. Eight women were given 200 mg of sulpiride im, and 4 of them received 200 μg of TRH 30 min later. In 4 women the order of the TRH and sulpiride injections was reversed. Six women were studied as controls.
Oral sulpiride treatment induced a significant Prl elevation from 14.6 ± 1.8 μg/l (mean ± sem) to 83.0 ± 4.0 μg/l, whereas the mean TSH levels did not change. Before sulpiride intake, TRH caused a mean maximal increment of 42.9 ± 4.7 μg/l in the Prl levels and an increment of 5.6 ± 0.9 IU/l in the TSH levels. During sulpiride administration, TRH caused a mean maximal increment of 16.5 ± 4.7 μg/l in the Prl levels and 3.5 ± 0.6 IU/l in the TSH levels. Both responses were significantly smaller (P < 0.001) during the sulpiride treatment than before.
Intramuscular injection of sulpiride raised the mean Prl concentration by 282 ± 32 μg/l (P < 0.001) and the mean TSH concentration by 0.5 ± 0.1 IU/l (P < 0.05). The Prl elevation was 502 ± 109 μg/l when sulpiride was injected after TRH. A preceding im sulpiride injection caused no changes in Prl and TSH responses to TRH.
These results show that in addition to Prl also TSH secretion is partially controlled by the dopaminergic system during early human pregnancy.
No proof of anorectic properties of pGlu-His-Gly in rats and mice
Authors: Knuth U. A. , Spiegelburg K. , Schneider H. P. G. 
Published: December 2008

Abstract.
Two groups of 7 rats were injected sc with 10 μg/d and 100 μg/d of pGlu-His-GlyOH or the same volume of saline for 20 days. No differences in body weight or food consumption could be detected during two months of observation.
The same negative results were obtained when 4 groups of 10 mice were treated with 0.17 μg/d pGlu-His-GlyOH or saline.
Regulation of humoral immunity in rats by pituitary hormones
Authors: Berczi Istvan , Nagy Eva , Kovacs Kalman , Horvath Eva 
Published: December 2008

Abstract.
Hypophysectomized female Fischer 344 and Wistar-Furth rats had severely impaired primary and secondary antibody responses to sheep red blood cells (SRBC). Mercaptoethanol-sensitive (IgM) and mercaptoethanol-resistant (IgG) antibodies were similarly affected. Titers to E. Coli 055:B5 lipopolysaccharide were also significantly decreased in such animals. The antibody response of hypophysectomized rats could be restored by syngeneic pituitary grafts when placed under the kidney capsule or by prolactin treatment. Growth hormone was less effective in this respect than prolactin. Treatment of normal rats with ACTH suppressed their antibody formation to SRBC. These results indicate that the pituitary gland has the potential to regulate humoral immune responses.
Radioimmunoassay of canine growth hormone
Authors: Eigenmann J. E. , Eigenmann R. Y. 
Published: December 2008

Abstract.
A sensitive radioimmunoassay (RIA) for canine growth hormone (GH) was developed. Antibodies were elicited in rhesus monkeys. One antiserum exhibited a working titer at a dilution of 1:500000. Radioiodination was performed enzymatically employing lactoperoxidase. Logit-log transformation and least squares fitting resulted in straight line fitting of the standard curve between 0.39 and 50 ng/ml. Formation of largemolecular [12SI]GH during storage caused diminished assay sensitivity. Therefore [125I]GH was re-purified by gel chromatography. Using this procedure, high and reproducible assay sensitivity was obtained. Tracer preparations were used for as long as 3 months after iodination. Diluted plasma from normal and acromegalic dogs resulted in a dose-response curve parallel to the standard curve. Canine prolactin exhibited a cross-reactivity of 2%. The within-assay coefficient of variation (CV) was 3.8 and the between-assay CV was 7.2%. Mean plasma GH concentration in normal dogs was 1.92 ± 0.14 ng/ml (mean ± sem). GH levels in acromegalic dogs were appreciably higher. Insulin-induced hypoglycaemia, arginine and ornithine administration resulted in inconsistent and sluggish GH increment. A better response was obtained by injecting a low dose of clonidine. Clonidine administration to hypopituitary dogs resulted in absent or poor GH increment.
Propranolol and the hypercalcaemia of thyrotoxicosis
Authors: Feely John 
Published: December 2008

Abstract.
The effect of propranolol on serum calcium was studied in 25 patients with thyrotoxicosis including 5 with hypercalcaemia. In patients with hypercalcaemia iv propranolol significantly reduced serum calcium. Oral therapy 160 mg/day reduced calcium non-significantly from 2.72 ± 0.09 (mean ± SD) to 2.59 ± 0.13 mmol/l, however on 320 mg/day the reduction (to 2.5 ± 0.15 mmol/l) was significant. In normocalcaemic patients oral propranolol did not influence serum calcium. Both in hyper- and normocalcaemic thyrotoxic patients propranolol increased (P < 0.01) serum phosphate.
Some unexpected effects of thyrotrophin on the metabolism of thyroid cells isolated from non-toxic goitre
Authors: Wadeleux P. A. , Winand R. J. 
Published: December 2008

Abstract.
In cultured cells of normal dog thyroid, thyrotrophin (TSH) has been shown to have a mitogenic effect. The present study suggests an opposite action in cells from human non-toxic goitre. After incubation of these cells with [3H]thymidine, a decreased incorporation into DNA is observed in the presence of TSH.
Whereas in dog thyroid cells the hormone enhances the incorporation of [3H]leucine and [14C]glucosamine into macromolecules, TSH inhibits the incorporation by human non-toxic goitre cells. Polyacrylamide gel electrophoresis analysis of the proteins present in the cell layer or released in the culture medium shows that the inhibition affects all the newly synthesized peptides, including the radioactive material co-migrating with the major band (330 000 daltons) observed with human purified thyroglobulin.
While several hydrolase activities are not influenced by TSH in dog thyroid cells, the hormone markedly decreases the activities of some hydrolases of thyroid cells from human non-toxic goitre.
Our results therefore suggest that, in cultured thyroid cells from human non-toxic goitre, TSH induces a resting state of the cells, characterized by reduced growth, reduced protein synthesis and reduced thyroglobulin hydrolysis.
Influence of medroxyprogesterone acetate (Provera) on plasma growth hormone levels and on carbohydrate metabolism
Authors: Eigenmann J. E. , Rijnberk A. 
Published: December 2008

Abstract.
Six elderly ovariohysterectomized dogs were given medroxyprogesterone acetate (MPA 10 mg/kg body weight) at 3 week intervals in a total of 5 injections. Mean growth hormone (GH) levels increased significantly after the third injection, continued to increase slightly after the fourth and fifth injections and remained significantly elevated over control levels as late as 16 weeks after the last MPA administration (P < 0.05). The mean glucose concentrations during iv glucose tolerance tests (IVGTT) were significantly elevated at 30, 45 and 60 min after a glucose load when performed after the third MPA injection. Following the second MPA injection, mean insulin levels were significantly elevated at rest, 30 and 45 min after glucose load. After the fourth and fifth MPA injections, mean insulin levels during IVGTT were significantly elevated at 30 min only.
These findings denote that (1) after a lag phase of several weeks MPA induces moderate GH increase in ovariohysterectomized dogs; (2) MPA administration causes moderate disturbance of glucose homoeostasis.
LH pattern in ovariectomised rats after continuous blood withdrawal: effects of different substitutions
Authors: Schneider H. Th. , Kraft K. , Breuer H. 
Published: December 2008

Abstract.
Plasma concentrations of LH and of sodium, potassium, total protein and haemoglobin were measured in ovariectomised rats during continuous blood withdrawal up to 180 min; 0.45 ml blood samples were taken every 10 min, the total volume of blood removed not exceeding 9 ml. Four groups of animals were studied: group A received no substitution (controls), group B was substituted with 0.9% NaCl-solution, group C with 3.5% polypeptide solution (Haemaccel), and group D with a suspension of washed erythrocytes from the blood removed. During blood withdrawal, the mean values of LH concentrations as well as the amplitudes of the rhythmic LH pulses remained constant in all the animals. However, the rate of pulses was reduced in the control animals and in the group receiving 0.9% NaCl-solution during the period between 90 and 180 min; in contrast no change was observed in the groups C and D during the whole period. The results presented here show that the characteristic LH pattern in ovariectomised rats is not affected by volume depletion, provided the blood is replaced by a solution containing either a polypeptide or a suspension of washed erythrocytes.
Effect of alloxan diabetes on kidney growth in intact and castrated mice
Authors: Broulik P. D. , Schreiber V. 
Published: December 2008

Abstract.
The mouse kidney is particularly responsive to the withdrawal or administration of androgens. The absence of endogenous androgens after castration led to decreased RNA synthesis and subsequent decrease in weight of the kidney. The induction of diabetes in 21 days castrated mice restored kidney weight. In intact mice made diabetic by iv injection of alloxan there was a increase in kidney weight. This increase was accompanied by a proportional inacrease in RNA. In mice hypertrophy was found to be the major factor in renal growth. When castration and diabetes were combined kidney weight did not fall as in the case of castration only but increased even above the kidney weight of intact animals. There was a parallel rise in RNA content of the kidney. Castration does not inhibit the renotrophic activity of alloxan diabetes in mice. Renal growth in alloxan diabetes is quite independent of the presence of androgens.
Ontogeny of gastric inhibitory peptide in the human gastro-intestinal tract and endocrine pancreas
Authors: Leduque P. , Gespach C. , Brown J. C. , Rosselin G. , Dubois P. M. 
Published: December 2008

Abstract.
The appearance and distribution of the gastro-intestinal hormone, gastric inhibitory peptide (GIP) were examined in the gastro-entero-pancreatic system of human foetuses, aged 5–24 weeks, by immunocytochemistry or radioimmunoassay. The first immunoreactive cells were observed in the gut from 16 weeks of gestation. The GIP-containing cells were localized preferentially in the villous epithelium of the small intestine. In the radioimmunoassay, the highest concentrations of immunoreactive GIP (IR-GIP) were detected from 13 to 21 weeks of gestation. The tissue concentration of IR-GIP was 68.10 ± 10.70 ng/g wet weight of duodenum, 30.29 ± 3.96 ng/g wet weight of jejuno-ileum and 3.05 ± 1.97 ng/g wet weight in the colon. Measurable amounts of IR-GIP (4.93 ± 1.57 ng/g wet weight of organ) were found from 9 to 12 weeks in the jejuno-ileal region. The ontogenic development of IR-GIP was studied in this region. From 13 to 21 weeks of gestation, the IR-GIP content per g of organ increased about 6-fold. In the endocrine pancreas, GIP antiserum No. R07 was potent in staining A cells from 14 weeks of gestation. In radioimmunological tests, no cross-reactions of the anti-GIP sera R 07 and GP 01 with heterologous peptides were observed. Labelling of paraffin and semi-thin sections was subjected not only to the usual specificity tests, but also to particularly extensive cross-reaction studies. GIP-like immunoreactivity was not inhibited by absorptions against heterologous peptides added at varying concentrations. The immunocytological and radioimmunological results are consistent with an eventual implication of GIP in the endocrine regulation of metabolism or in the development of the gastro-entero-pancreatic system during the intrauterine life in man.
In vitro inhibition of trophoblast maturation and expansion of early rat blastocysts by an oestrogen antagonist
Authors: Roy S. K. , Sengupta J. , Paria B. C. , Manchanda S. K. 
Published: December 2008

Abstract.
Rat blastocyst development and expansion were studied in an in vitro culture system. Early blastocysts collected from rats on the morning of day 5 were shown to develop normally and underwent expansion when placed in bovine serum albumin supplemented culture medium for 12 h at 37°C. Nafoxidine, an oestrogen antagonist, prevented embryo expansion when added to the culture medium, and it was found that if oestradiol-17β was added to this medium this inhibitory effect was removed and the embryos again expanded. Ethanol, used as a solvent for steroids, and cholesterol were added to the medium containing nafoxidine but the blastocysts still remained unexpanded after 12 h in culture. These results suggest a need for oestrogen action during blastocyst expansion in vitro. Cultured rat blastocysts were subjected to histochemical study for acid phosphatase (ACPase) and leucylnaphthylamidase (LNAse). In unexpanded blastocysts ACPase was found to be low while LNAse activity was higher when compared with enzyme distribution patterns in expanded blastocysts.
Growth hormone secretion in pubertal and adult subjects
Authors: Minuto Francesco , Barreca Antonina , Ferrini Silvano , Mazzocchi Giancarlo , Del Monte Patrizia , Giordano Giulio 
Published: December 2008

Abstract.
GH responsiveness to insulin-induced hypoglycaemia and its circadian secretion were studied in a group of subjects in different pubertal stages.
The GH peak after insulin was minimal in stage 1 boys (7.6 ± 1.3 (sem) ng/ml) and increased progressively, in parallel with pubertal maturation, reaching a maximum in the adult state (20 ± 4.0 ng/ml); the basal value was superimposable in all groups studied.
The circadian secretion showed a sleep-related surge which was almost identical in the different stages; however in pubertal stage 1 boys multiple secretory peaks were observed, mainly during waking hours. A statistically significant difference (P < 0.05) was observed in the mean concentration recorded during the day with a maximum in stage 1 boys (2.7 ± 0.2 ng/ml) and a gradual decrease to a minimum in adults (1.2 ± 0.3 ng/ml).
This pattern seems to suggest that a pulsatile rhythm is present in boys, similar to that observed for gonadotrophins.