bluuebunny/crossref_metadata_2025 huggingface dataset:
Progesterone receptors in rat brain and uterus: dependence on the hormonal milieu
Authors: Al-Khouri H. , Greenstein B. D.
Published: December 2008

Cytosols were incubated from the hypothalamus and mid-brain and from the uterus, and incubated with [3H]progesterone alone or in the presence of excess radioinert steroid to reveal saturable binding sites. Bound and free hormone were separated by gel filtration. Scatchard analysis of the binding sites yielded evidence for only one class of binding sites of high affinity and limited capacity. The binding components in the hypothalamus and uterus appeared to fluctuate during the oestrous cycle, attaining a nadir at metoestrus, while those in the mid-brain were apparently unchanged. During pregnancy hypothalamic [3H]progesterone-binding sites appeared to lose affinity for the steroid while in the uterus the affinity for the steroid was unchanged but the absolute numbers of binding sites were greatly increased at day 10. It is concluded, both from studies of the properties intrinsic to the binding reaction and from endocrine correlates, that the macromolecular progesterone-binding components in the brain may be receptors for the hormone and that there may be differences between the properties of progesterone receptors in different tissues. Furthermore, during pregnancy there may be qualitative changes in the neural progesterone receptors which are not mediated by oestradiol.

J. Endocr. (1985) 107, 159–162
Oestrogen-2/4-hydroxylase activity in the rat brain during lactation and throughout the oestrous cycle
Authors: Brown C. G. , White N. , Jeffcoate S. L.
Published: December 2008

Oestrogen-2/4-hydroxylase activity was measured in whole brain, thalamus, amygdala, hypothalamus and pituitary gland of lactating rats and in whole brain of rats on different days of the oestrous cycle. Enzyme activity was increased in whole brain and in each of the brain regions examined (with the exception of the amygdala) in lactating rats. This increase in enzyme activity was associated with an increase in serum prolactin levels. During the oestrous cycle, enzyme activity in whole brain was higher on metoestrus and dioestrus than on pro-oestrus and oestrus. The decrease in enzyme on pro-oestrus was associated with an increase in both serum oestradiol and prolactin levels. These results are consistent with the hypothesis that changes in oestrogen-2/4-hydroxylase activity are associated with changes in prolactin and oestradiol secretion and may play a regulatory role in reproduction.

J. Endocr. (1985) 107, 191–196
Progesterone and oestradiol receptor concentration and translocation in uterine tissue of rabbits treated with indomethacin
Authors: Cao Z.-D. , Jones M. A. , Harper M. J. K.
Published: December 2008

The purpose of this study was to determine whether endogenous prostaglandins are involved in the regulation of sexual steroid receptor concentration and cytosol to nucleus translocation in the rabbit uterus. The animals were injected s.c. with indomethacin (10 mg/kg) twice daily on days 5 and 6 and on the morning of day 7 of pregnancy or pseudopregnancy and killed 2 h after the last injection. The indomethacin treatment did not change progesterone and oestradiol serum concentrations compared with animals injected with vehicle only. No differences were observed either in progesterone receptor or oestradiol (pregnant animals only) receptor concentration and intracellular distribution in endometria of indomethacin-treated or control animals. In an extended experiment indomethacin given to oestrogen-pretreated ovariectomized rabbits did not inhibit the nuclear progesterone receptor accumulation induced by a single progesterone injection. These results suggest that there is no direct relationship between prostaglandins and sexual steroid receptors in the rabbit uterus.

J. Endocr. (1985) 107, 197–203
Inhibin-like activity in ovarian homogenates of prepubertal female rats and its physiological significance
Authors: Sander H. J. , Meijs-Roelofs H. M. A. , Kramer P. , van Leeuwen E. C. M.
Published: December 2008

The presence and physiological significance of ovarian inhibin-like activity (ILA) in immature rats was studied by measuring ILA in ovarian homogenates and by studying the short-term changes in serum concentrations of FSH and LH after unilateral or bilateral ovariectomy. Inhibin-like activity in ovarian homogenates was estimated using an in-vitro bioassay system with dispersed rat anterior pituitary cells and subsequent measurement of FSH and LH levels in the spent pituitary cell medium. Inhibin-like activity, expressed in units/ovary, was undetectable in 13-day-old ovaries, was present in 18-day-old ovaries (5·8 units/ovary) and rose significantly to a value of 29·1 units/ovary on day 23. Another significant rise was seen between 28 and 33 days of age, with ILA reaching a value of 66·4 units/ovary, a value still well below that found in adult dioestrous ovaries (155·6 units/ovary). In the bioassay no systematic dose-dependent influence on LH secretion was found. Serum concentrations of FSH after unilateral or bilateral ovariectomy at 18 days of age showed no change at 5 h and a significant (P < 0·05) increase compared with sham-operated controls at 24 h after operation. At 23, 28 and 33 days of age significant increases in FSH concentration were seen at 5 and 8 h after both unilateral and bilateral ovariectomy. At 24 h after unilateral ovariectomy, FSH had returned to the control values in these rats, whereas after bilateral ovariectomy a further increase in FSH was seen. Concentrations of LH generally varied widely and, compared with the situation after sham-operation, did not show a systematic trend of change during the 24-h period after unilateral or bilateral ovariectomy.

It was concluded that ILA is present in immature rat ovaries from the age of 18 days and increases, to a still sub-adult value, until at least 33 days of age. A physiological role for ILA, as a short-term regulator of FSH secretion seems to be present from at least 23 days of age and may account for the decreasing FSH concentrations seen during the late-prepubertal period, when ovarian steroids alone cannot explain the low FSH levels measured.

J. Endocr. (1985) 107, 251–257
Endogenous opioids and the control of seasonal LH secretion in Soay rams
Authors: Ebling F. J. P. , Lincoln G. A.
Published: December 2008

Soay rams were treated with naloxone and/or morphine at different stages of their annual reproductive cycle to study the role of endogenous opioid peptides in the control of pulsatile LH secretion. The responses in intact rams were compared with those shown by pinealectomized (PNX) or superior cervical ganglionectomized (SCGX) rams which had a different annual testicular cycle. Naloxone (4–6 mg/kg i.v.) given to intact rams at four times of the year induced significant increases in LH pulse frequency in the breeding season in September and December, but minimal responses in the non-breeding season in June. Similar treatments given to PNX or SCGX rams induced good responses in March, June and September and the poorest response in December; the different seasonal pattern between the intact and PNX/SCGX rams was correlated with differences in the timing of their testicular cycles.

Morphine (1 mg/kg i.v.) induced a significant decrease in LH pulse frequency when given to intact rams in October, but no significant effects were observed when morphine was given to sexually inactive rams in early July. Naloxone (1 mg/kg i.v.) given concurrently with morphine in October reversed the suppressive effect and resulted in an actual increase in LH pulse frequency above pretreatment levels. Morphine-treated rams showed normal LH responses to injections of LH-releasing hormone (LHRH) indicating that the site of opiate inhibition was on hypothalamic LHRH secretion rather than on pituitary LH release.

Chronic treatment of intact and PNX rams with naloxone 1 mg/kg every 4 h for 7 days) in April and October produced the expected acute increase in LH pulse frequency in the intact rams in October, and at both times of year in the PNX rams, however there was no sustained increase in LH secretion in response to chronic naloxone in any of the treatment groups. The response to the second naloxone injection was much reduced and was absent after 3 days; responsiveness to naloxone was restored within 2 days of stopping the chronic treatment.

The overall results indicate that an endogenous opioid mechanism is involved in the tonic inhibition of LH secretion and that this mechanism is most active in the breeding season when both naloxone and morphine have marked effects on pulsatile release of LH. Regulation of endogenous opioids in the hypothalamus may be part of the mechanism by which environmental factors modulate steroid negative-feedback control of LHRH and thus LH secretion in seasonally breeding mammals.

J. Endocr. (1985) 107, 341–353
Effects of intracranial androgen on the development of masculine ultrasonic vocalizations in the Mongolian gerbil (Meriones unguiculatus)
Authors: Holman S. D. , Hutchison J. B.
Published: December 2008

The effects of testosterone propionate (TP) on brain mechanisms involved in the sexual differentiation of ultrasonic vocalizations were examined in Mongolian gerbils (Meriones unguiculatus). Treatment of neonatal females with TP fully masculinized the rate of emission of the upsweep precopulatory ultrasound during adult sexual interactions with oestrous females. Intracranial implantation of small crystals of TP mixed with cholesterol (65 ng) into females 1–15 h after birth also masculinized the upsweep vocalization emitted in adulthood. Implants of TP positioned in the hypothalamic area had a significantly greater masculinizing effect than TP implants outside this region, or pure cholesterol implants. Two other sexually dimorphic vocalizations, the modulated (mainly precopulatory) and unmodulated (mainly copulatory) calls were masculinized by systemic TP, but intracranial TP had no significant masculinizing action on these calls. Genital structures of females which received neonatal injections of TP were strongly virilized in that their clitorides were lengthened and male-type cornified spines were present on the glans. Females which had received intracranial implants of TP were not virilized peripherally in adulthood. We conclude that testosterone or its metabolites have a direct hypothalamic effect on the development of masculine upsweep vocalizations. Because the other vocalizations were insensitive to intracranial TP, the underlying neural tissues may have different thresholds of response to androgen.

J. Endocr. (1985) 107, 355–363
Circadian variations in plasma calcium and calcitonin: effect of calcium deficiency and fasting
Authors: Lausson S. , Staub J. F. , Milhaud G. , Perault-Staub A. M.
Published: December 2008

Circadian fluctuations of plasma calcium and immunoassayable calcitonin levels were studied in normal and calcium-deficient 2-month-old rats. The relationship between these parameters was also studied in animals which had been fasted for short periods. The plasma calcium rhythm persisted and was even amplified in rats placed on a 4-week calcium-deficient diet. In these rats, as in normal rats, the plasma calcium concentration diminished during the dark period. Calcitonin levels increased at the onset of the feeding period in normal rats but, in calcium-deficient rats, the pattern changed completely, with a major peak at the end of the light period and remaining at a low level during the dark feeding period. This modification of calcitonin rhythmicity appeared to be dependent on the degree of calcium deficiency. Fasting had little effect on calcitonin rhythms in either normal or calcium-deficient rats.

It is concluded that the calcitonin rhythm is relatively independent of feeding per se and that there appears to be no simple relationship between plasma calcium and calcitonin concentrations. It is suggested that the results may best be interpreted as reflecting the presence of rhythmic endogenous phenomena which are intrinsic to calcium metabolism and its regulation in the rat.

J. Endocr. (1985) 107, 389–395
MONOCLONAL ANTIBODY-MEDIATED ENHANCEMENT OF GROWTH HORMONE ACTIVITY IN VIVO
Authors: Holder A. T. , Aston R. , Preece M.A. , Ivanyi J.
Published: December 2008

This work demonstrates that complexing hGH with monoclonal antibody EBl (MAB-EBl) can produce a striking potentiation of the somatogenic actions of hGH in vivo in Snell dwarf mice. In short-term experiments significant increases in cartilage metabolism and body weight were noted; these responses were dose-dependent for both MAB-EBl and hGH concentration. Increased growth was also observed in long-term experiments. In marmosets where MAB-EBl cross-reacts with endogenous GH, MAB-EBl alone enhanced the actions of endogenous GH. A new perspective may be necessary to incorporate these results into the current concept of antibody action.
REDUCED TISSUE ANDROGEN RECEPTORS IN THE CONGENITALLY OBESE MALE ZUCKER RAT
Authors: Bannister P. , Whitaker E. M.
Published: December 2008

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

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

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

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

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

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

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

[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

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

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

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

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

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

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

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
Relationship between growth and function of human thyroid cells in culture
Authors: Ollis C. A. , Davies R. , Munro D. S. , Tomlinson S.
Published: December 2008

Subconfluent human thyroid cells in monolayer, isolated from thyrotoxic tissue or non-toxic goitres obtained at surgery, responded to the addition of epidermal growth factor (EGF) with an increase in cell growth as measured by increased incorporation of [3H]thymidine into trichloroacetic acid-precipitable material. The growth response to EGF was concentration-dependent and the characteristics of the responses were the same using EGF from murine or human sources. With concentrations which stimulated growth, EGF was found to inhibit human thyroid cell function as measured by the release of radioimmunoassayable tri-iodothyronine into the incubation medium. Thyrotrophin (TSH) was also found to stimulate human thyroid cell growth but at concentrations far lower than those used to stimulate thyroid cell function in this system. The effect of EGF on the differentiating action of TSH on human thyroid cells in culture was also investigated; the association of thyroid cells into two-dimensional follicular structures produced by the incubation of thyroid cells at a high cell density with TSH was found to be inhibited by the addition of EGF.

J. Endocr. (1986) 108, 393–398
Prolactin release, oestrogens and proliferation of prolactin-secreting cells in the anterior pituitary gland of adult male rats
Authors: Pérez R. L. , Machiavelli G. A. , Romano M. I. , Burdman J. A.
Published: December 2008

Relationships among the release of prolactin, the effect of oestrogens and the proliferation of prolactin-secreting cells were studied under several experimental conditions.

Administration of sulpiride or oestradiol released prolactin and stimulated cell proliferation in the anterior pituitary gland of adult male rats. Clomiphene completely abolished the rise in cell proliferation, but did not interfere with the sulpiride-induced release of prolactin. Treatment with oestradiol plus sulpiride significantly increased serum prolactin concentrations and the mitotic index compared with the sum of the stimulation produced by both drugs separately. Bromocriptine abolished the stimulatory effect of oestradiol on the serum prolactin concentration and on cell proliferation. In oestradiol- and/or sulpiride-treated rats, 80% of the cells in mitoses were lactotrophs. The remaining 20% did not stain with antisera against any of the pituitary hormones. The number of prolactin-secreting cells in the anterior pituitary gland significantly increased after the administration of oestradiol or sulpiride.

The results demonstrate that treatment with sulpiride and/or oestradiol increases the proliferation and the number of lactotrophs in the anterior pituitary gland of the rat.

J. Endocr. (1986) 108, 399–403
Effects of LH and an LH-releasing hormone agonist on different second messenger systems in the regulation of steroidogenesis in isolated rat Leydig cells
Authors: Themmen A. P. N. , Hoogerbrugge J. W. , Rommerts F. F. G. , van der Molen H. J.
Published: December 2008

The stimulation of steroid production in Leydig cells by LH is accompanied by increased cyclic AMP levels, activation of protein kinase A, increased phosphorylation of at least six phosphoproteins and requires protein synthesis. However, an LH-releasing hormone agonist (LHRH-A) can stimulate steroid production without stimulation of cyclic AMP levels. In the present study we have shown that LH action involves calcium fluxes through the plasma membrane, in addition to activation of protein kinase A. The action of LHRH-A, in contrast, does not require calcium fluxes and is not potentiated by 1-methyl-3-isobutylxanthine, indicating that cyclic AMP is not involved. Extracellular calcium is required for the action of both LH and LHRH-A. An increase in intracellular calcium concentration due to the effect of ionophore A23187 did not stimulate steroidogenesis and had deleterious effects on intracellular adenosinetriphosphate levels. LH and 4β-phorbol-12-myristate-13-acetate (PMA), an activator of protein kinase C, both stimulated phosphorylation of proteins of 17 000 and 33 000 mol. wt, whereas LHRH-A had no effect. However, compared with the effect of LH, PMA had a much smaller effect on steroid production, indicating that even if protein kinase C may be activated by LH its role in the regulation of steroid production may be less important than the role of protein kinase A. Action of LHRH-A does not appear to be mediated by calcium fluxes, protein kinase C activation or active protein phosphorylation.

J. Endocr. (1986) 108, 431–440
Colloidal carbon blocks oestrogen-induced migration of eosinophils to the uterus and the uterine water imbibition response
Authors: López M. , Castrillón M. A. , Tchernitchin A. N.
Published: December 2008

Oestrogen induces a migration of eosinophil leukocytes to the uterus where, it is suggested, these cells mediate several responses to hormone stimulation. To investigate the mechanism of the recognition of the uterus by the eosinophils, the present study describes the effect of a blockade of the rat reticulo-endothelial system with colloidal carbon on oestrogen-induced uterine eosinophilia, and other responses to oestrogen stimulation that, it has been suggested, are mediated by eosinophils.

In the absence of oestrogen colloidal carbon induced an increase in the number of eosinophils in mesometrium but not in endometrium with myometrium, and a slight oedematous reaction in deep endometrium. Colloidal carbon abolished the oestrogen-induced increase in the number of eosinophils in endometrium with myometrium and drastically decreased the oestrogen-induced increase in uterine wet weight and the endometrial oedematous responses 6 h after the administration of oestrogen.

The present results agree with the hypothesis that most uterine water imbibition is mediated by eosinophils and suggest a possible mechanism for the interaction of colloidal carbon with eosinophil migration to the uterus.

J. Endocr. (1986) 109, 89–95
Transcortin and vitamin D-binding protein levels in mouse serum
Authors: Faict D. , De Moor P. , Bouillon R. , Heyns W. , Heiniger H.-J. , Corrow D. , Lesaffre E.
Published: December 2008

The influence of age, sex and strain on the serum concentration of transcortin (corticosteroid-binding globulin) and vitamin D-binding protein (DBP) in mice was investigated. The effect of age was studied in two strains, C57BL/6JPfd and BALB/cmHeAPfd. The concentration of transcortin and DBP increased with age. In young animals the concentration of each protein showed a significant strain difference, which disappeared in older mice for DBP, but not for transcortin. In 7-day-old animals, no sex difference was observed for either protein, but in older animals a clear sex difference was found for transcortin. Adult males tended to have somewhat higher levels of DBP than adult females, but this difference was significant only on day 70.

The variation in transcortin and DBP levels was further investigated in a large number of mouse strains. The DBP concentration did not markedly vary among strains (5·98–9·65 μmol/l in males and 5·08–8·85 μmol/l in females). Transcortin, however, showed marked strain variations, ranging from 0·72 to 2·06 μmol/l in males and from 1·02 to 4·55 μmol/l in females and there was a significant correlation (r= 0·66, n= 26, P<0·001) between the mean transcortin levels in males and females of different strains. Interstrain variation was much higher than intrastrain variation or variation among related strains, suggesting that the transcortin concentration is largely controlled by genetically determined factors.

There was a significant correlation (r= 0·82, n = 9, P<0·01) between the mean corticosterone and transcortin concentrations (measured at 21.00 h). Consequently, differences in the free corticosterone levels in the serum of various mouse strains were smaller than the differences in the total corticosterone concentrations. The affinity of transcortin for corticosterone was similar in all but one strain; however, transcortin of the RIIIS/J strain showed a lower affinity for corticosterone.

J. Endocr. (1986) 109, 141–147
Steroid binding to feather follicles in the chicken
Authors: Kovács K. , Péczely P. , Szelényi Z.
Published: December 2008

Steroid binding profiles in chicken feather follicles were studied in vitro. Progesterone and promegestone were bound specifically with high affinity (dissociation constant = 7·79 nmol/l in females and 2·0 nmol/l in males) and with low capacity to the high-speed supernatant fraction (cytosol) of homogenized feather follicles. The number of progestin-binding sites was significantly (P < 0·01) higher in females than in males (1·35 ± 0·07 (mean ± s.d.) vs 0·605 ± 0·15 pmol/mg protein). Significant cross-competition was observed between progestins and glucocorticoids for the binding sites. The heat-activated progestin–receptor complexes bound specifically to DNA-cellulose in vitro. The DNA-cellulose binding was 36·6% of the total specific binding. The presence of progestin-binding sites in the feather follicles implies a direct action of progesterone in this structure, which may be an important factor in the regulation of moulting. The lack of oestrogen binding to the cytosol prepared from the feather follicles suggests different regulation of progestin receptors in different target organs.

J. Endocr. (1986) 109, 187–191
Five new insulin-producing cell lines with differing secretory properties
Authors: Carrington C. A. , Rubery E. D. , Pearson E. C. , Hales C. N.
Published: December 2008

Five cell lines have been derived from a rat transplantable islet cell tumour using two different methods. The lines differ in morphology and contain and release different amounts of insulin and glucagon (insulin content, 1–90 pmol/106 cells; insulin release, 6–250 pmol/106 cells per 24 h; glucagon content, < 0·005–35 pmol/106 cells; glucagon release, < 0·05– 10 pmol/106 cells per 24 h). All the lines responded to the presence of the secretagogues leucine (20 mmol/l) plus theophylline (5 mmol/l) by increasing the rate of release of insulin approximately twofold. A high extracellular concentration of potassium (40 mmol/l) caused a three- to tenfold calcium-dependent increase in release of insulin and a parallel release of glucagon. Increasing the concentration of glucose from 2·8 to 16·7 mmol/l did not alter the rate of insulin release by any of the cell lines.

J. Endocr. (1986) 109, 193–200