bluuebunny/crossref_metadata_2025_split huggingface dataset:
REDUCED TISSUE ANDROGEN RECEPTORS IN THE CONGENITALLY OBESE MALE ZUCKER RAT
Authors: Bannister P. , Whitaker E. M. 
Published: December 2008

ABSTRACT
Androgen receptor (AR) concentrations were measured in the prostates and livers of the infertile congenitally obese male Zucker rat and their fertile non-obese litter-mates. In obese rats AR concentrations were significantly lower in both the liver (p<0.001) and the prostates (p<0.01) of the obese rats compared with the non-obese rats, despite similar plasma testosterone concentrations in both phenotypes. These findings suggest that a potential cause for the infertility observed in the obese Zucker rat is a reduced sensitivity of target tissues to circulating androgens.
Renal adenylate cyclase assay for biologically active parathyroid hormone: clinical utility and physiological significance
Authors: Auf'mkolk B. , Hesch R.-D. 
Published: December 2008

ABSTRACT
The stimulation of cyclic AMP production by human renal cortical membranes in the presence of the GTP analogue 5′-guanylimidodiphosphate and a calcium chelator represents a homologous assay system for the evaluation of biologically active parathyroid hormone (bioPTH) in human serum. Bioactive PTH was raised above normal (normal range: undetectable to 4·6 pmol human PTH(1–34) per 1) in 13/17 (76%) patients with primary hyperparathyroidism, in 5/6 (83%) patients with surgically proven hyperparathyroidism secondary to chronic renal failure, in 4/5 (80%) patients with hyperparathyroidism secondary to hypocalcaemia, in all three patients with pseudohypoparathyroidism, in 5/17 (29%) patients with osteoporosis and in 1/9 (11%) patients with renal stones and/or hypercalciuria. Bioactive PTH correlated positively with immunoreactive PTH (iPTH) measured with a radioimmunoassay predominantly recognizing the middleand carboxyl-terminal region of the PTH molecule (r = 0·503, P<0·001). A positive correlation (r = 0·572, P<0·05) was found between values of serum calcium and bioPTH in the group with primary hyperparathyroidism. Immunoreactive PTH did not correlate significantly with calcium in this group. In the other patients except those who had chronic renal failure, a negative correlation between serum calcium and both bioPTH and iPTH was observed (P<0·01). When alkaline phosphatase was compared with bioPTH in all patients, the correlation was positive (r = 0·390, P<0·01); no significant correlation existed between iPTH and alkaline phosphatase in the patients studied. When comparing the metabolic status of the bones with bioPTH, there was a higher incidence of severe bone lesions in those patients with primary hyperparathyroidism who had extremely raised levels of bioPTH. In osteoporosis no simple relationship was apparent.
J. Endocr. (1986) 108, 9–15
Immunocytochemical localization of corticosteroid-binding globulin in rat tissues
Authors: Kuhn R. W. , Green A. L. , Raymoure W. J. , Siiteri P. K. 
Published: December 2008

ABSTRACT
Previous studies utilizing steroid-binding assays have suggested that corticosteroid-binding globulin (CBG)-like glucocorticoid binding sites are present in various tissues of the rat. It is not known, however, whether such binding reflects the intracellular presence of CBG derived from serum or a special class (type III) of receptors. In order to elucidate this problem, immunocytochemical localization of rat CBG was carried out using a specific antiserum prepared against rat serum CBG and the peroxidase-antiperoxidase technique. Positive staining was found in certain cells of the liver, the distal and/or convoluted tubules of the kidney, the uterus, the follicular cells of the thyroid, and some cells of the anterior pituitary. Other tissues including heart, muscle, thymus, hypothalamus, supraoptic and paraventricular nuclei, and diaphragm were negative. The presence of immunoreactive CBG in specific cells of some glucocorticoid-responsive tissues and not others raises interesting questions concerning the transport of glucocorticoids and their mechanism of action.
J. Endocr. (1986) 108, 31–36
Effect of hypothyroidism on pituitary cytoplasmic concentrations of messenger RNA encoding thyrotrophin β and α subunits, prolactin and growth hormone
Authors: Franklyn J. A. , Lynam T. , Docherty K. , Ramsden D. B. , Sheppard M. C. 
Published: December 2008

ABSTRACT
Thyroid hormones may directly regulate gene expression in the anterior pituitary. In order to examine this possibility we have studied the effect of hypothyroidism in the rat on pituitary cytoplasmic concentrations of messenger RNA (mRNA) encoding thyrotrophin (TSH) β and α subunits, prolactin and GH. We demonstrated a marked increase in TSH β and α subunit mRNA, accompanied by a decrease in GH mRNA, in the hypothyroid state, changes largely reversed by thyroid hormone replacement. We have thus shown a direct influence of thyroid status on the pretranslational events occurring in pituitary hormone synthesis. The simultaneous rise in cytoplasmic TSH β and α mRNA levels and fall in GH mRNA in hypothyroidism suggests that thyroid status exerts a differential effect on the expression of these genes.
J. Endocr. (1986) 108, 43–47
Characterization of pro-opiomelanocortin-derived peptides in pituitary and ectopic adrenocorticotrophin-secreting tumours
Authors: Hale A. C. , Besser G. M. , Rees L. H. 
Published: December 2008

ABSTRACT
The molecular forms of pro-opiomelanocortin in plasma of normal subjects and plasma and tissue extracts from patients with disorders of the hypothalamic-pituitary-adrenal axis have been characterized using gel filtration chromatography under acid dissociating conditions, and the molecular forms further investigated by high pressure liquid chromatography and affinity chromatography. A large molecular weight MSH/ACTH fragment was observed in all plasma samples chromatographed, although the proportions of this fragment were significantly greater in patients with the ectopic ACTH syndrome. A similar profile was observed in tumour extracts: a greater proportion of large molecular weight precursors was observed. Immunoreactive-γ-MSH in extracts of ectopic tumours displayed marked and variable heterogeneity, and affinity chromatography with Concanavalin A-Sepharose indicated that this was due to differential glycosylation. High pressure liquid chromatography of a peak of amino terminal pro-opiomelanocortin (N-POC(1–76)) and 22 000 mol. wt MSH/ACTH indicated two peaks in each peptide, again possibly due to differential glycosylation. A possible neurointermediate lobe origin of atypical invasive pituitary tumours is discussed.
J. Endocr. (1986) 108, 49–56
Na-K-ATPase-inhibiting and glucose-6-phosphate dehydrogenase-stimulating activity of plasma and hypothalamus of the Okamoto spontaneously hypertensive rat
Authors: Millett J. A. , Holland S. M. , Alaghband-Zadeh J. , de Wardener H. E. 
Published: December 2008

ABSTRACT
The plasma of normal man and the rat, and an acetone extract of hypothalamus from the rat, have an ability to inhibit Na-K-ATPase which is related directly to salt intake. The ability of the plasma to inhibit Na-K-ATPase is raised in essential hypertension.
The ability of plasma and of an acetone extract of hypothalamus from six spontaneously hypertensive (SHR) rats and six normotensive control (WKY) rats to inhibit Na-K-ATPase of fresh guinea-pig kidney was studied using cytochemical bioassay techniques. With a validated assay, which measures the capacity of biological samples to stimulate glucose-6-phosphate dehydrogenase (G6PD) as an index of their capacity to inhibit Na-K-ATPase, the mean G6PD-stimulating ability of the plasma from the SHR and the WKY rat was 772·3 ± 48·1 units/ml and 12·5 ± 2·6 units/ml respectively (P < 0·01) and of the hypothalamic extracts it was 2·2 ± 1·7 × 108 and 4·5 ± 1·8 × 104 units/hypothalamus (P < 0·01). With a semi-quantitative cytochemical assay, which measures Na-K-ATPase activity directly, plasma and an acetone extract of hypothalamus from the spontaneously hypertensive rat had much greater capacities to inhibit Na-K-ATPase than plasma and extract from the WKY rat.
These raised levels of Na-K-ATPase inhibitory activity in the plasma of the SHR rat are similar to the highest values found in the plasma of patients with essential hypertension. The results suggest that the substance responsible for the increased capacity of the plasma to inhibit Na-K-ATPase may originate from the hypothalamus and that it may, in part, be involved in the mechanisms which induce the rise of arterial pressure in inherited forms of hypertension.
J. Endocr. (1986) 108, 69–73
Anti-fertility effect of passive immunization against progesterone is influenced by genotype
Authors: Rider V. , Wang M.-Y. , Finn C. , Heap R. B. , Feinstein A. 
Published: December 2008

ABSTRACT
The anti-fertility effect of a monoclonal progesterone antibody injected i.p. 32 h after mating is influenced by genotype since a single dose of 5·7 nmol immunoglobulin G successfully blocked the establishment of pregnancy in BALB/c but not in F1 hybrid mice (CBA male × BALB/c female). Progesterone concentrations in circulation were significantly higher at days 3 and 4 after mating in F1 females compared with those of the BALB/c stock. Moreover, the pattern of mitotic activity in the endometrium after passive immunization differed between the two genotypes. In treated BALB/c mice there was no increase in mitotic activity in stromal cells at days 3, 4 and 5 after mating (in contrast to BALB/c control females in which the number of stromal mitoses increased sharply). In F1 females there was a transient effect of antibody at day 3 (no increase in stromal mitoses but enhanced mitotic activity in the glandular epithelium compared with F1 control females), and subsequently a normal increase in mitotic divisions in stromal cells. The hypothesis is proposed that passive immunization against progesterone at 32 h after mating will only block the establishment of pregnancy in genotypes in which there is a gradual, rather than a steep rise in circulating progesterone concentrations during the preimplantation period. In F1 mice, high concentrations of circulating progesterone at days 3 and 4 of pregnancy apparently over-ride the effect of antibody and facilitate the normal development of stromal mitotic activity associated with the onset of implantation.
J. Endocr. (1986) 108, 117–121
Transformation of androgen receptors from mouse submandibular glands by gel chromatography
Authors: Sato N. , Ohara-Nemoto Y. , Ota M. 
Published: December 2008

ABSTRACT
[3H]Methyltrienolone-bound and unbound androgen receptors from mouse submandibular glands bound to DNA-cellulose to a similar extent after gel chromatography. The receptors sedimented at 6 S in a low-salt gradient whereas if receptors were transformed with KCl (0·4 mol/l) they sedimented at 4 S. On DEAE-anion exchange chromatography both were eluted at a concentration of 0·07 mol KCl/l. These results suggest that two states of transformed androgen receptors exist. A 6 S transformed receptor may well derive by partial dissociation of an 8 S non-transformed receptor and this is caused by gel chromatography. Molybdate ions completely prevent both the transformation induced by gel chromatography and the secondary transformation during DEAE-anion exchange chromatography.
J. Endocr. (1986) 108, 123–127
Aspects of the neuronal and endocrine components of reflex milk ejection in conscious rabbits
Authors: Summerlee A. J. S. , Paisley A. C. , O'Byrne K. T. , Fairhall K. M. , Robinson I. C. A. F. , Fletcher J. 
Published: December 2008

ABSTRACT
Nursing behaviour and reflex milk ejection were studied over 257 suckling periods in 26 Californian rabbits. Detailed plasma profiles of oxytocin were obtained for 161 suckling periods in 16 animals. Plasma oxytocin was detected by radioimmunoassay in serial samples of 0·2 ml blood collected during nursing. Oxytocin titres were below the lower limit of the assay (5 pmol/l) before suckling, and started to rise at a rate of 2·8 ± 0·8 (s.d.) pmol/l per s 10–30 s after the onset of suckling. Peak levels of hormone were 345 ± 113 pmol/l and were attained towards the end of nursing. In 33 of these experiments simultaneous records of activity from oxytocin neurones were taken whilst chronically sampling the blood. Each neurone gave an average of seven bursts of neurosecretory activity in suckling. Onset of this bursting pattern of discharge began 5–24 s before the rise in plasma oxytocin was detected. Oxytocin neurone activity alone was monitored in a further 55 suckling periods in eight rabbits. A marked relationship between the duration of suckling period, milk yield, peak oxytocin levels and the length of neurosecretory bursts was demonstrated over the course of lactation. All four parameters increased in parallel from day 1 to reach maximal values on days 15–20 of lactation then started to wane until the doe ceased nursing her litter on days 25–27 of lactation.
J. Endocr. (1986) 108, 143–149
Characterization of the insulin-binding sites in turtle thyroid microsomes
Authors: Turyn D. , da Silva R. S. M , Marques M. , Dellacha J. M. 
Published: December 2008

ABSTRACT
The characteristics of the specific binding of labelled insulin to turtle thyroid microsomes were investigated. Binding experiments were performed in Krebs–Ringer bicarbonate buffer (pH 7·4) at 25 or 4 °C for different periods of time. Dissociation of the labelled insulin from the binding sites was also evaluated. It was found that the binding is dependent on time, temperature and microsomal protein concentration, with an optimum pH of 8·0. Unlabelled insulin and pro-insulin competed with the labelled insulin, binding in direct proportion to their biological activities, while glucagon and growth hormones did not compete for the binding sites. Scatchard plot analysis established the presence of binding sites of high and low affinities, and the rate of dissociation of bound insulin was considerably increased by the addition of unlabelled insulin. Both results are compatible with a negative co-operativity site–site interaction model. Trypsin abolished the insulin binding. These findings indicate that the microsomes from the turtle thyroid gland contain specific binding sites for insulin. However, preincubation of microsomes with phospholipase C or S-adenosyl-l-methionine (SAM), or incubation in the presence of 2 mol NaCl/l did not increase the specific insulin binding. Therefore, the binding properties are similar to those observed in mammalian insulin-responsive tissues except for the absence of the effects of 2 mol NaCl/l, phospholipase C or SAM, which suggests the absence of masked insulin-binding sites.
J. Endocr. (1986) 108, 157–162
Vasopressin secretion in normotensive black and white men and women on normal and low sodium diets
Authors: Crofton J. T. , Dustan H. , Share L. , Brooks D. P. 
Published: December 2008

ABSTRACT
The plasma concentration and the 24-h urinary excretion of vasopressin were studied in normal black and white men and women on a normal sodium (150 mmol/day) diet for 3 days and a low sodium (9 mmol/day; furosemide, 1 mg/kg on first day) diet for 4 days. During the normal sodium diet, the 24-h urinary excretion of vasopressin was significantly (P<0·05) higher in men than in women and higher (P<0·05) in black than in white subjects. Corresponding differences in plasma vasopressin concentrations (P<0·05 to 0·01) were observed, with the exception that the difference between white men and women was not statistically significant. These data suggest that under basal conditions the secretion of vasopressin is higher in men and black subjects than in women and white subjects, although differences in the metabolic clearance of vasopressin cannot be ruled out. Reduction in sodium intake resulted in a significantly (P<0·01) decreased excretion of vasopressin in all groups except black women, but had no effect on plasma vasopressin concentrations. Significant (P<0·01) differences with respect to sex and race persisted for vasopressin excretion, but not for plasma vasopressin concentrations. Sex- and race-related differences in vasopressin could not be attributed to differences in blood pressure, plasma volume or plasma sodium concentration. The physiological consequences of these differences in vasopressin remain to be determined.
J. Endocr. (1986) 108, 191–199
Temporal relationship between the onset of daily gonadotrophin surges and of puberty in female golden hamsters
Authors: Donham R. S. , Creyaufmiller N. , Lyons T. J. , Stetson M. H. 
Published: December 2008

ABSTRACT
Daily rhythms of LH and FSH release commence on day 16 or 17 of age in the prepubertal female golden hamster, 2–3 weeks before regular 4-day oestrous cycles begin. We tested the hypothesis that the daily surges of gonadotrophin regulate, at least in part, rate of sexual maturation and, hence, age at puberty. We predict that an advance or a delay in the initiation of the daily rhythm should result in a corresponding advance or delay in the day of puberty. In the first test, the onset of daily gonadotrophin surges was advanced by gonadotrophin-releasing hormone (GnRH) injections; in the second test, the onset was delayed by daily injection of phenobarbital sodium (PB). The day of the first of at least three consecutive post-ovulatory vaginal discharges was used as an index of the age at puberty. Gonadotrophin-releasing hormone (50 ng/0·1 ml saline per animal) was injected at 16.30 h on days 8–17 of age. These injections initiated a daily mid-afternoon surge of LH about 8 days before the onset of the daily rhythm of gonadotrophins in salineinjected controls and the day of first vaginal discharge was advanced by 4 days compared with saline-injected controls (32·0±1·8 days vs 36·3±1·0 days; P < 0·001). Phenobarbital sodium (100 mg/kg body wt), injected at 13.30 h from 16 to 25 days of age, blocked daily surges of gonadotrophin observed in controls by day 18. These injections of PB delayed by about 8 days the appearance of daily LH surges and the day of first vaginal discharge was delayed 8 days compared with saline-injected controls (43·0±1·2 vs 35·4±1·1; P<0·001). Control animals injected with PB after the critical period, i.e. at a time when daily gonadotrophin surges are not affected, demonstrated first vaginal oestrus at the same age as saline-injected controls. These results support the proposal that daily rhythms of hormone release by the brain and pituitary regulate the processes of sexual maturation.
J. Endocr. (1986) 108, 219–224
Human pharyngeal and sellar pituitary glands: differences and similarities revealed by an immunocytochemical study
Authors: Puy L. A. , Ciocca D. R. 
Published: December 2008

ABSTRACT
Fifteen pharyngeal and sellar pituitary glands, obtained at autopsy from unselected adult patients, were compared in an attempt to elucidate the functional significance of the pharyngeal pituitary. The study was carried out using light microscopy and an indirect peroxidase technique to detect the presence of prolactin, GH, ACTH, LH, FSH, TSH and lipotrophin (LPH) immunoreactive cells. A quantitative analysis of these cell types in each gland was performed. Neither the pharyngeal nor the sellar pituitaries were abnormal in six cases. In this group the average percentage of immunoreactive cells in the sellar vs the pharyngeal pituitary was 11·3 vs 7·4 for FSH cells, 13·3 vs 4·4 for LH cells, 6·4 vs 5·2 for TSH cells, 14 vs 1·5 for ACTH cells, 13·1 vs 6 for LPH cells, 29·4 vs 5·2 for GH cells and 21·2 vs 8·5 for prolactin cells. A comparative statistical evaluation of the seven hormone-producing cell types indicated that, in most cases, the percentage of immunoreactive cells was significantly higher in the sellar pituitary. Examination of serial sections revealed hyperplasia, with or without microadenomas, in nine sellar pituitaries. In these abnormal cases most of the pharyngeal pituitary glands showed hyperplasia of the same cell type as was found hyperplastic in the sellar adenohypophysis. However, hyperplasia restricted to the sellar pituitary was also seen. There were two cases in which the pharyngeal pituitary was almost lacking in immunoreactive cells; in one of them the sellar pituitary had GH and prolactin cell hyperplasia. The results obtained confirm that under normal conditions the pharyngeal pituitary is not an important source of adenohypophyseal hormones. They also suggest that the pharyngeal pituitary, despite its capacity to respond at a cellular level, has a limited potential in terms of volume, and that it is not developmentally programmed to replace the sellar adenohypophysis except when the latter has a serious pathological condition.
J. Endocr. (1986) 108, 231–238
Specificity of gonadotrophin-releasing hormone binding sites of the human corpus luteum: comparison with receptors of rat pituitary gland
Authors: Bramley T. A. , Menzies G. S. , Baird D. T. 
Published: December 2008

ABSTRACT
The effects of a number of analogues of gonadotrophin-releasing hormone (GnRH) on the binding of a radiolabelled GnRH agonist (GnRH-A; d-Ser(But)6, des Gly10]GnRH-ethylamide) to homogenates of human corpus luteum (CL) and rat pituitary tissue were compared. Specific binding was inhibited by GnRH and GnRH-like peptides only. Both the C-terminal amide and N-terminal region of the GnRH molecule were required for binding in both tissues. However, amino acid substitutions at position 6 markedly enhanced, and at position 8 markedly reduced, binding potencies in rat pituitary tissue compared with human CL binding sites. These results indicate that GnRH-binding sites of rat pituitary and human luteal tissue have a similar degree of specificity for GnRH-like peptides, and a similar requirement for both N- and C-terminal regions of the peptide, but that differences in specificity related to the mid-chain region of GnRH exist between human luteal and rat pituitary binding sites.
J. Endocr. (1985) 000, 000–000
Non-specific esterase: a specific and useful marker enzyme for Leydig cells from mature rats
Authors: Molenaar R. , Rommerts F. F. G. , van der Molen H. J. 
Published: December 2008

ABSTRACT
The presence of non-specific esterase activity is correlated with different Leydig cell characteristics: 3β-hydroxysteroid dehydrogenase (3β-HSD), human chorionic gonadotrophin binding and LH-stimulated steroid production. This indicates that esterase can be used as a marker enzyme for Leydig cells. Esterase, however, has also been used as a marker enzyme for macrophages. We have compared, using biochemical and histochemical techniques, the esterase activity of Leydig cell preparations from mature and immature rats and of preparations enriched in testicular or peritoneal macrophages. Leydig cells were identified by staining for 3β-HSD, and macrophages by phagocytosis of fluorescent beads. Leydig cell preparations from mature rats showed an approximately 400-fold higher esterase activity than peritoneal macrophage preparations and an approximately 50-fold higher activity than testicular macrophage preparations. Leydig cell preparations from mature rats showed a 60-fold higher esterase activity than Leydig cell preparations from immature rats.
Differences in esterase activity were also demonstrated histochemically. Leydig cells from mature rats showed positive esterase staining after 30 s at room temperature. Testicular macrophages showed esterase activity after staining for 3 min. Only approximately 25% of the 3β-HSD-positive cells from immature rats showed esterase activity after staining for 6 min. Esterase is therefore a useful marker enzyme for Leydig cells from mature rats and can be of help in studies concerning the development of these cells.
J. Endocr. (1986) 108, 329–334