bluuebunny/crossref_metadata_2025 huggingface dataset:
SITE OF ORIGIN OF THE PULSATILE SECRETION OF LUTEINIZING HORMONE IN LONG-TERM OVARIECTOMIZED RATS
Authors: SCHUILING G. A. , GNODDE H. P.
Published: December 2008

If long-term ovariectomized rats are treated with the long-acting barbiturate, sodium phenobarbitone, the well-known pulsatile secretion of LH is depressed, resulting in a constant, still raised, plasma LH level. This indicates that in all probability ovariectomized rats secrete LH in both a tonic and a pulsatile way, only the latter being sensitive to phenobarbitone treatment.

Constant infusions of synthetic LH-RH into phenobarbitone-treated ovariectomized rats induced a steadily increasing plasma LH concentration without pulsations, whereas pulsatile infusions of the releasing hormone, following a constant infusion, resulted in a pulsatile secretion of LH. This indicates that the pulsatile secretion of LH in ovariectomized rats is the result of a pulsatile secretion of the hypothalamic releasing hormone; the pituitary gland itself is not the site of origin of the phenomenon.
CORTICOSTEROID PRODUCTION BY THE HUMAN FOETUS: EVIDENCE FROM ANALYSIS OF URINE FROM WOMEN PREGNANT WITH A NORMAL OR AN ANENCEPHALIC FOETUS
Authors: CAWOOD MARION L. , HEYS R. F. , OAKEY R. E.
Published: December 2008

The quantities of nine corticosteroids in 24 h urine samples collected by pregnant women (nine with normal foetuses and nine with anencephalic foetuses) were measured after hydrolysis with β-glucuronidase and separation by paper chromatography. The excretion (μmol/24 h, mean ± s.d.) of pregnanetriol (0·85 ± 0·17), 3α,17α-dihydroxy-5β-pregnan-20-one 17α-hydroxypregnanolone, 0·55 ± 0·17), 3α,17α,21-trihydroxy-5β-pregnan-20-one (tetrahydro-11-deoxycortisol, 0·17 ± 0·14) and tetrahydrocorticosterone (0·65 ± 0·26) by women with an anencephalic foetus was significantly lower (P < 0·01 or <0·05) than the excretion of these compounds by women with a normal foetus (pregnanetriol, 2·42 ± 0·62; 17α-hydroxypregnanolone, 2·72 ± 0·69; tetrahydro-11-deoxycortisol, 0·56 ± 0·37; tetrahydrocorticosterone, 1·95 ± 0·94). These differences suggest that the adrenal of the normal foetus contributes to the quantity of pregnanetriol, 17α-hydroxypregnanolone, tetrahydro-11-deoxycortisol and tetrahydrocorticosterone in maternal urine. The excretion of tetrahydrocortisol, tetrahydrocortisone, tetrahydrodeoxycorticosterone, cortol and cortolone were similar in both groups of subjects.

No evidence was obtained therefore to indicate the secretion of cortisol or deoxycorticosterone by the foetal zone of the adrenal of the undisturbed human foetus in late gestation.
ABNORMAL LUTEINIZING HORMONE RESPONSE PATTERNS TO SYNTHETIC GONADOTROPHIN RELEASING HORMONE IN PATIENTS WITH POLYCYSTIC OVARIAN SYNDROME
Authors: KATZ M. , CARR P. J.
Published: December 2008

Basal gonadotrophin and sex steroid levels and responses to an intravenous injection of 100 μg gonadotrophin releasing hormone (Gn-RH) have been studied in 15 patients with polycystic ovaries. Mean basal LH concentration was raised and an excessive, exaggerated and prolonged response was observed after Gn-RH treatment, but patients could further be subdivided into two functional groups on the basis of their basal LH values and LH response patterns. Evidence was also produced which suggested a breakdown in the negative feedback mechanism in these patients.
AGEING AND OVARIAN Δ5-3β-HYDROXYSTEROID DEHYDROGENASE IN THE PREGNANT MOUSE
Authors: WEHRENBERG W. B. , GOTTLIEB S. F. , ALBRECHT E. D.
Published: December 2008

Aged (12- to 14-month-old) C57BL oestrous mice exhibited significantly lower (P < 0·001) ovarian Δ5-3β-hydroxysteroid dehydrogenase (3β-HSD) concentration, specific activity and total content than young (3-month-old) oestrous mice, suggesting a decrease in the potential of the older animals to produce ovarian Δ4-3-oxosteroids. Mice in both age groups maintaining pregnancy to 10 or 18 days post coitum (p.c.) had similar values for activity of ovarian 3β-HSD. In the aged females in which foetal resorption had occurred, the majority of foetuses had been resorbed by 10 days p.c. However, ovarian 3β-HSD activity in these animals was not significantly different from that of young or aged mice maintaining pregnancy. By day 18, however, ovarian dehydrogenase activity in aged females failing to maintain pregnancy had decreased significantly. It is suggested that foetal death in aged mice is not the result of a deficiency in ovarian 3β-HSD, but rather may initiate luteal regression and consequently a decline in 3β-HSD.
INCORPORATION OF 14C-LABELLED AMINO ACIDS INTO CORTICOTROPHIN-LIKE INTERMEDIATE LOBE PEPTIDE AND α-MELANOCYTE-STIMULATING HORMONE BY THE RAT PITUITARY NEUROINTERMEDIATE LOBE IN VITRO, AND THE IDENTIFICATION OF FOUR NEW PARS INTERMEDIA PEPTIDES
Authors: SCOTT A. P. , LOWRY P. J. , VAN WIMERSMA GREIDANUS TJ. B.
Published: December 2008

At least seven radioactive peptides, which fractionated on Biogel P6, were found in rat neurointermediate lobes after incubation for 6 h with [14C]proline. Only three of these could be tentatively identified; one as α-melanocyte-stimulating hormone (α-MSH) and two as forms of corticotrophin-like intermediate lobe peptide (CLIP). One other crossreacted partially with a β-melanocyte-stimulating hormone (β-MSH) antiserum, was acidically charged and eluted on Biogel P6 in roughly the same position as ACTH. The other three peptides showed no resemblance to α-MSH, CLIP, β-MSH or ACTH.
EFFECTS OF CORTICOSTERONE ON ADRENOCORTICOTROPHIN-INDUCED MITOCHONDRIAL DIFFERENTIATION WITH SPECIAL REFERENCE TO 11β-AND 18-HYDROXYLATION
Authors: SALMENPERÄ M. , KAHRI A. I. , SAURE A.
Published: December 2008

The effects of corticosterone in concentrations found in adrenal venous plasma on ACTH-induced changes in cultured cortical cells derived from foetal rat adrenals were studied. Corticosterone at a concentration of 5·7 × 10−5 mol/l completely inhibited mitochondrial differentiation to fasciculate-like morphology. The same cultures revealed significant inhibition of 11β- and 18-hydroxylation compared with cultures treated with ACTH only. This was shown by the reduced formation of corticosterone and 18-OH-deoxycorticosterone (48%, P < 0·001) and simultaneous enhancement of deoxycorticosterone formation (33%, P < 0·05) from added [4-14C]progesterone. Similar inhibition was observed when dibutyryl cyclic AMP replaced ACTH as an inducer of differentiation. Lower concentrations of corticosterone (1·2 × 10−5 and 2·4 × 10−5 mol/l) inhibited ACTH-stimulated formation of corticosterone and 18-OH-deoxycorticosterone from endogenous precursors.

The results demonstrate that corticosterone regulates the stage of differentiation in cultured adrenocortical cells. The possible role of corticosterone in the regulation of growth and steroidogenic capacity of the adrenal cortex is discussed.
SERUM GONADOTROPHIN LEVELS DURING DEVELOPMENT IN MALE, FEMALE AND ANDROGENIZED FEMALE RATS AND THE EFFECT OF GENERAL DISTURBANCE ON HIGH LUTEINIZING HORMONE LEVELS
Authors: MACKINNON P. C. B. , MATTOCK J. M. , TER HARR M. B.
Published: December 2008

Serum LH, FSH and prolactin levels were measured in blood samples which were obtained by decapitation from groups of female, neonatally androgenized female and male Wistar rats at 2-day intervals from birth to maturity. An increase in serum FSH levels was observed between 4 and 24 days of age in both the female and androgenized female groups, while a much later increase, between 28 and 44 days of age, occurred in the males. Serum prolactin levels increased gradually from birth in all three groups until adult levels were attained. In contrast, serum LH levels were in general low in all three groups of animals, although very high levels (> 7 ng/ml) were recorded in 22 out of 168 females and 8 out of 192 males between 4 and 28 days of age, as well as in adult males; occasional high LH levels were also seen in the androgenized females.

The nature of the high serum LH levels was investigated in anaesthetized and unanaesthetized immature females by serial blood sampling using a number of techniques. Unexpectedly, only three out of 58 animals had high LH levels: two of these showed an episodic form of LH release during which levels increased to peak values and then declined within a period of about 30 min. On investigation it was found that general disturbance within the 45 min before decapitation could inhibit high LH levels in females aged between 23 and 30 days.
ON DIFFERENCES BETWEEN THE PREOVULATORY LUTEINIZING HORMONE SURGES OF 4- AND 5-DAY CYCLIC RATS
Authors: SCHUILING G. A. , DE KONING J. , ZÜRCHER A. F.
Published: December 2008

Preovulatory LH surges were studied in rats with ovarian cycles of 4 days (4d-rats) and 5 days (5d-rats). In 5d-rats the maximal peak height was about twice that observed in 4d-rats, whereas in 4d-rats peaks occurred about 1·5 h later than in 5d-rats and were much less consistently timed.

From experiments in which LH releasing hormone (LH-RH) was infused into pentobarbitone-blocked pro-oestrous rats, it was concluded that (a) differences between the two types of preovulatory LH surges originate within the central nervous system, and (b) prooestrous LH-RH secretion may not be restricted to the period in which increased LH levels in blood were found, but may exceed this period for a considerable time.
EFFECTS OF OESTRADIOL-17β, HYPOPHYSECTOMY AND AGE ON CYTOPLASMIC OESTRADIOL-17β RECEPTOR SITES IN RAT TESTIS INTERSTITIAL TISSUE
Authors: DE BOER WILLEM , MULDER EPPO , VAN DER MOLEN H. J.
Published: December 2008

After administration of oestradiol-17β to intact mature and immature rats, a decrease in the testicular concentration of specific oestradiol-binding sites was observed within 1 h. The binding capacity was replenished starting about 3 h after oestradiol administration and after 5 h the oestrogen receptor level had returned to control values. Exposure of intact animals to oestradiol-17β for longer periods (up to 24 h) did not result in an increase of receptor levels in testicular cytosol.

Mature animals which were hypophysectomized for periods of up to 10 days did not show a significant change in the number of specific oestradiol-binding sites in either total testicular tissue or dissected interstitial tissue. At 15 days or longer periods after hypophysectomy, an apparent increase in receptor concentrations in total testicular cytosol was observed due to a relative increase in the amount of interstitial tissue.

A specific oestradiol-binding protein is present in plasma of immature male rats aged less than 30 days. This plasma protein could also be demonstrated in the cytosol of testes of immature rats. In contrast to the cytosol receptor, which shows a moderate affinity for diethylstilboestrol (DES), the plasma protein did not bind DES. The sedimentation values of the plasma protein and the oestradiol receptor were 4 S and 8 S respectively. These differences in characteristics made it possible to demonstrate the presence of the oestradiol receptor in addition to the binding protein in testicular cytosol of rats from 14 days of age onwards. The nuclear receptor for oestradiol-17β could be demonstrated after incubation of testicular tissue of rats from 4 days of age onwards.
SELECTION FOR HIGH AND LOW ADRENAL WEIGHT IN MICE
Authors: BADR F. M.
Published: December 2008

Four strains of mice were used to found a heterogeneous stock from which one line was selected for high adrenal weight/100 g body weight and another line for low adrenal weight/100 g body weight. By the eighth generation of selection, two stocks of mice were produced, one with adrenals whose absolute weight was greater than any of the parental strains. The realized heritability estimates were 75% for females and 67% for males during the period of selection, showing that a large component of variation in adrenal weight was genetic in origin.

Asymmetry in response to selection was also noticed and attributed to possible variation in adrenal structure between sexes. Estimates of variances in each generation, particularly the eighth, did not show any decline which suggested that further responses to selection would be possible with further selection.
PRE-OVULATORY CHANGES IN STEROIDOGENESIS IN OVARIES FROM IMMATURE RATS TREATED WITH PREGNANT MARE SERUM GONADOTROPHIN
Authors: ECKSTEIN B. , LERNER N. , YEHUD S.
Published: December 2008

The metabolism of progesterone in the 1000 g supernatant fraction of homogenates of ovaries from PMSG-treated immature rats was determined. As early as 52 h after a single injection of 50 i.u. PMSG, still before the LH surge, 5α-pregnane-3α,20α-diol was identified as the main metabolite, together with smaller quantities of 3α-hydroxy-5α-pregnan-20-one and 5α-androstane-3α,17β-diol. Similar incubations of untreated rat ovaries at the same age did not produce 5α-pregnane-3α,20α-diol. The quantities of 3α-hydroxy-5α-pregnan-20-one and 5α-androstane-3α,17β-diol were reduced in PMSG-treated rat ovaries as compared with control ovaries. When progesterone metabolism was examined 64 h after PMSG administration, 5–7 h after the peak of the LH surge but still before ovulation, 75% of the substrate was converted to 5α-pregnane-3α,20α-diol, while 3α-hydroxy-5α-pregnan-20-one as well as 5α-androstane-3α,17β-diol could not be detected.
METABOLISM OF ANDROGENS IN VITRO BY HUMAN FOETAL SKIN
Authors: SHARP F. , HAY J. B. , HODGINS M. B.
Published: December 2008

Fresh scalp, genital, chest and axillary skin from human foetuses of 12–41 weeks' maturity was incubated in Krebs' improved Ringer I medium with [7α-3H]dehydroepiandrosterone, [7α-3H]testosterone and [7α-3H]androstenedione. The metabolites identified were androstenedione, 5α-androstane-3,17-dione, androsterone, 3-epiandrosterone, 5α-dihydrotestosterone, 5α-androstane-3α,17β-diol, 5α-androstane-3β,17β-diol, 5-androstene-3β,17β-diol and testosterone. The results provide evidence for the presence of 3β-hydroxysteroid dehydrogenase, Δ4–5 isomerase, 17β-hydroxysteroid dehydrogenase, Δ4-3-oxosteroid-5α-reductase and 3α-hydroxysteroid dehydrogenase in human foetal skin. There were quantitative differences in the various enzyme activities between different body sites and skin specimens of different gestational age. 5α-Reductase activity was particularly high in genital skin. 3β-Hydroxysteroid dehydrogenase Δ4–5 isomerase activity was low in skin from a 12-week foetus, but high in skin specimens from 28-, 38- and 41-week foetuses. 17β-Hydroxysteroid dehydrogenase activity was already high in the skin of the 12-week foetus and remained so in the older foetuses. These results were correlated with the development of the foetal sebaceous glands, and were in general agreement with a parallel enzyme histochemical study. The role of androgen metabolism in human foetal skin is discussed.
STIMULATION OF GROWTH IN THE LITTLE MOUSE
Authors: BEAMER W. G. , EICHER EVA M.
Published: December 2008

The new mouse mutation little (lit) in the homozygous state causes a pituitary deficiency involving at least growth hormone (GH) and prolactin. The resultant growth failure of lit/lit mice was shown to be reversed by experimental conditions that enhanced levels of GH or GH and prolactin in the circulation. Two measures of growth, actual weight gain and bone dimension, were significantly improved by the physiological processes of pregnancy and pseudopregnancy, by extra-sellar graft of a normal mouse pituitary, and by treatment with GH but not prolactin. These data confirmed pituitary dysfunction as the basic defect caused by the mutation lit and showed that the GH deficiency is responsible for growth failure. However, the biological site of gene action, the pituitary or hypothalamus, has not been established.

Little mice exhibit a number of characteristics similar to those of human genetic ateleotic dwarfism Type 1, namely genetic inheritance, time of onset of growth retardation, proportionate skeletal size reduction, and pituitary GH deficiency.
INFLUENCE OF THE VAGUS AND CAROTID SINUS NERVES ON PLASMA RENIN IN THE CAT
Authors: BROSNIHAN KATHLEEN B. , TRAVIS R. H.
Published: December 2008

Influence of the vagus and carotid sinus nerves on peripheral plasma renin was studied in the cat. Bilateral cervical vagotomy was followed by a sustained increase in plasma renin concentration (PRC) of anaesthetized cats made hypervolaemic by intravenous saline infusions. The increase in PRC is attributable to right vagotomy. Bilateral carotid artery occlusion in anaesthetized hypervolaemic cats, either with or without prior vagotomy, or with mechanical prevention of a rise in systemic blood pressure, resulted in no statistically significant increases in peripheral venous PRC, compared with the control animals.
CONCENTRATION OF OESTROGENS AND ANDROGENS IN HUMAN OVARIAN VENOUS PLASMA AND FOLLICULAR FLUID THROUGHOUT THE MENSTRUAL CYCLE
Authors: McNATTY K. P. , BAIRD D. T. , BOLTON A. , CHAMBERS P. , CORKER C. S. , McLEAN H.
Published: December 2008

The concentrations of androstenedione, testosterone, oestrone and oestradiol-17β were measured in peripheral and ovarian venous blood and follicular fluid of women at various stages of the menstrual cycle. The concentration of oestradiol was similar in small follicles (diameter < 8 mm) at all stages of the menstrual cycle and in large follicles (diameter ⩾ 8 mm) except during the mid- and late follicular phase when the concentration reached a peak (∼ 1500 ng/ml).

The concentration of androstenedione was lowest in large preovulatory follicles at mid-cycle at a time when the secretion into the ovarian vein was markedly increased. The concentration of testosterone in large follicles (⩾ 8 mm) was unchanged during the follicular phase whereas in small follicles there was a peak at mid-cycle.

The rise in the concentration of testosterone and androstenedione at mid-cycle in peripheral plasma may be due to increased secretion by the preovulatory follicle into the ovarian vein. It is suggested that the relatively low concentration of androstenedione in follicular fluid of the preovulatory follicle arises from increased aromatization by granulosa cells in the course of oestrogen synthesis.
METAL–ANDROGEN INTERRELATIONSHIPS IN CARCINOMA AND HYPERPLASIA OF THE HUMAN PROSTATE
Authors: HABIB F. K. , HAMMOND G. L. , LEE I. R. , DAWSON J. B. , MASON M. K. , SMITH P. H. , STITCH S. R.
Published: December 2008

Zinc and cadmium concentrations were measured by atomic absorption spectroscopy in normal and pathological human prostates. Our studies confirm that the values of zinc in normal tissue [6·84 ± 1·21 (s.e.m.) μmol/g] and benign prostatic hypertrophy (BPH) (6·91 ± 1·19 μmol/g) are similar, while in neoplastic tissues zinc concentrations were significantly lower (2·61 ± 0·45 μmol/g). The Cd2+ levels in BPH (23·11 ± 3·28 nmol/g) were, on the other hand, considerably higher than those found for normal tissues (5·15 ± 0·62 nmol/g). In agreement with other published reports, Cd2+ concentrations were found to be markedly increased in carcinomatous tissue (129·79 ± 22·22 nmol/g). No correlation was however established between the values for the two metals in either type of prostatic tissue.

An established specific radioimmunoassay was used for the measurement of testosterone and dihydrotestosterone (DHT) and a distinct pattern emerged upon comparing these results with those for the zinc and cadmium concentrations. It appears that the concentrations of DHT in benign hypertrophy and of testosterone and DHT in carcinoma were inversely proportional to the levels of Zn2+ in abnormal tissue. In contrast, the DHT levels in the hypertrophied and malignant tissue were proportional to the Cd2+ concentrations.
THE DEVELOPMENT OF ADRENOCORTICOTROPHIN-SENSITIVE ADENYLATE CYCLASE ACTIVITY IN THE FOETAL RABBIT ADRENAL: A CORRELATED BIOCHEMICAL AND MORPHOLOGICAL STUDY
Authors: ALBANO JANET D. M. , JACK PATRICIA M. , JOSEPH TERESA , GOULD R. P. , NATHANIELSZ P. W. , BROWN B. L.
Published: December 2008

Proliferation of the smooth endoplasmic reticulum, the site of some hydroxylating steroidogenic enzymes in foetal adrenocortical cells, is the first major change in the process of their differentiation into steroidogenic tissue. This was observed in our ultrastructural studies on foetal rabbit adrenals to begin at about day 19 of development. Morphological changes in the mitochondria, the site of production of other steroidogenic enzymes, occurred at about day 24. The elongated or rod-shaped forms of the earlier stages became flattened and rounded by this time, while the cristae were transformed from a flattened lamellar type of the earlier stages to the tubulo-vesicular form of the adult. Other changes observed included an increase in microvilli and in cell size, with a concomitant increase in thickness of the gland.

Adenylate cyclase activity in foetal adrenal homogenates was assessed in response to sodium fluoride (NaF) and ACTH. All preparations responded to NaF. While good responses to ACTH were observed at days 24, 27, 28 and in the neonate, there was a lack of any significant response in the day 19 gland. Foetal ACTH was depressed by administration of cortisol, and the effects of this treatment on both the morphological changes and adenylate cyclase activity was reassessed. The response of foetal adrenals to ACTH was depressed by this treatment and differentiation of the mitochondria was arrested.

These results suggest a circumscribed period for the development of ACTH-sensitive adenylate cyclase coinciding with the time at which final differentiation of the mitochondria is completed. Furthermore, both the differentiation of the mitochondria and the development of ACTH-sensitive adenylate cyclase in the foetal adrenal may be dependent on foetal ACTH secretion.
ROLE OF VASOPRESSIN IN THE MITOTIC RESPONSE OF RAT BONE MARROW CELLS TO HAEMORRHAGE
Authors: HUNT N. H. , PERRIS A. D. , SANDFORD P. A.
Published: December 2008

Two days after a severe haemorrhage plasma calcium concentrations and bone marrow mitotic activity in rats were significantly increased and so remained for a further 5–6 days until the haematocrit had returned to normal. The first 48 h after bleeding were characterized by hypocalcaemia. During this phase two significant peaks in mitotic activity were observed at 4 and 18 h after haemorrhage. The mitotic surge 4 h after bleeding was still present in adrenalectomized and parathyroidectomized animals but in rats which were either hypophysectomized or had congenital diabetes insipidus this mitotic response was absent. Vasopressin was shown to stimulate bone marrow mitotic activity both in vivo and in vitro whereas angiotensin, aldosterone and erythropoietin had no rapid, direct mitogenic action on these cells. This novel hypophysial–bone marrow system suggests that vasopressin may assist in post-haemorrhagic recovery in blood cell numbers in the circulation.
STATES OF ACTIVATION OF CHICK KIDNEY ADENYLATE CYCLASE INDUCED BY PARATHYROID HORMONE AND GUANYL NUCLEOTIDES
Authors: MICHELANGELI V. P. , HUNT N. H. , MARTIN T. J.
Published: December 2008

Several aspects of the activation of adenylate cyclase by guanosine 5′-triphosphate (GTP), 5′-guanylylimidodiphosphate (Gpp(NH)p) and bovine parathyroid hormone (bPTH) have been studied in chick kidney plasma membrane preparations. GTP (10−4 mol/l), Gpp(NH)p (10−4 mol/l) and bPTH (10 i.u./ml) activated adenylate cyclase without any significant time lag. However a 2 min delay was observed before the activity of the enzyme increased after the addition of bPTH (−6 → + 34) to incubations.

The early (0–3 min) effects of GTP and Gpp(NH)p upon chick kidney adenylate cyclase activity were antagonized by the addition of the alternative guanyl nucleotide. After 5 min of incubation with kidney plasma membranes, Gpp(NH)p induced a stable state of activation of adenylate cyclase which was not reversible by subsequent addition of GTP. GTP did not induce an irreversible state of enzyme activation. In pre-incubation studies, GTP did not produce a persistent enzyme activation and did not modify the effect of Gpp(NH)p added subsequently at the incubation stage. Gpp(NH)p produced a stable state of activation of adenylate cyclase which was not inhibited by addition of GTP at the incubation stage.

Bovine PTH (2–34) inhibited the effect of bPTH upon adenylate cyclase activity when the native hormone (10 i.u./ml) had been incubated with plasma membranes for up to 8 min before addition of the analogue (5 μg/ml). Incubation of plasma membranes with bPTH (2–34) for as little as 10 s prevented activation of adenylate cyclase by subsequent addition of bPTH. This pattern was confirmed in pre-incubation studies. After pre-incubation of kidney membranes with bPTH and bPTH (2–34), followed by washing, an acid extract of the membranes contained immunoreactive bPTH. Gpp(NH)p produced a greater increase in adenylate cyclase activity in membranes pre-incubated with bPTH or bPTH (2–34) than in membranes pre-incubated with buffer alone, suggesting that the hormone and analogue facilitated the interaction of Gpp(NH)p with adenylate cyclase.
OESTROGEN-INDUCED UTERINE PROTEIN: PRESENCE OF ASSOCIATED PHOSPHOPROTEIN PHOSPHATASE ACTIVITY BEFORE OESTROGEN TREATMENT
Authors: MAIRESSE N. , GALAND P.
Published: December 2008

The phosphoprotein phosphatase (PPPase) activity that is found associated with oestrogeninduced protein(s) is not itself induced by oestrogen. Indeed, this activity was found at the same electrophoretic position (i.e. the position of the oestrogen-induced protein) and in equal amounts relative to the total PPPase activity, whether the cytosol fraction from control or from stimulated uteri was tested.
THE USE OF CORTICOTROPHIN PRODUCTION BY ADENOHYPOPHYSIAL TISSUE IN VITRO FOR THE DETECTION AND ESTIMATION OF POTENTIAL CORTICOTROPHIN RELEASING FACTORS
Authors: BUCKINGHAM JULIA C. , HODGES J. R.
Published: December 2008

The cytochemical assay for ACTH has been adapted into a method for the detection and determination of potential corticotrophin releasing factors. Of the many putative transmitter substances tested, only the posterior pituitary polypeptides resembled hypothalamic extracts in causing dose-related increases in both pituitary ACTH content and release. Vasotocin was the most active of the compounds studied and, unlike the vasopressins, its dose–response relationships closely resembled those of hypothalamic extracts. The increase in ACTH release induced by hypothalamic extract or vasopressin was reduced by corticosterone, cortisol or progesterone but not by testosterone or oestradiol, but the increase in pituitary ACTH content was not affected by any of these steroids.
RELEASING FACTOR AND HORMONAL CHANGES IN THE HYPOTHALAMIC-PITUITARY-GONADOTROPHIN AND -ADRENOCORTICOTROPHIN SYSTEMS BEFORE AND AFTER BIRTH AND PUBERTY IN MALE, FEMALE AND ANDROGENIZED FEMALE RATS
Authors: CHIAPPA SHARON A. , FINK G.
Published: December 2008

The hypothalamic content of LH releasing factor (RF), pituitary ACTH and pituitary and plasma LH and FSH were measured by radioimmunoassay from foetal Day 15 to postnatal Day 65. Bioassayable corticotrophin releasing activity was also measured during the postnatal period. Hypothalamic LH-RF was detectable as early as foetal Day 15, increasing gradually until postnatal Day 2 and then steeply between Days 5 and 16. The levels of LH-RF were similar in both male and normal female rats until Day 41, after which the increase which had been occurring from Day 16 continued in the male but not the female. In female rats treated with testosterone propionate neonatally ('androgenized females') the hypothalamic content of LH-RF at Day 9 was significantly less than that in the male or normal female, levels reaching those found in the latter two groups by Days 16–22. The lower level of LH-RF in the androgenized female was associated with pituitary gonadotrophin and plasma FSH levels which were lower than in the normal female until Day 30. In the normal female, vaginal opening was associated with a marked drop in hypothalamic LH-RF content and in pituitary LH and FSH, but in the androgenized female, vaginal opening occurred while hypothalamic LH-RF and pituitary LH levels were still rising. The peaks in pituitary FSH and LH and in plasma LH seen on Days 22, 30 and 41, respectively, in the normal female were each delayed by 8–9 days in the androgenized female. In all three types of animal there was a significant drop in plasma FSH between Days 50 and 65 which was associated with a significant increase in pituitary FSH in the male and a significant decrease in pituitary FSH in the androgenized female rats. The day 17 foetal pituitary gland also contained ACTH, and again levels of this hormone rose steeply between Days 5 and 9. In contrast to the gonadotrophins, there was a marked divergence between the pituitary content and concentration of ACTH: content rose while concentration remained relatively steady after Day 9. There was no major difference in pituitary ACTH levels between the three types of animal throughout the study; however, around Days 16 and 50, corticotrophin releasing activity was higher in males and androgenized females compared with that in normal females.
5-ENE-3β-HYDROXYSTEROID DEHYDROGENASE OF HUMAN AND BOVINE ADRENOCORTICAL ENDOPLASMIC RETICULUM: SOLUBILIZATION AND FRACTIONATION
Authors: EASTMAN A. R. , NEVILLE A. M.
Published: December 2008

Protein moieties of various molecular sizes and possessing 5-ene-3β-hydroxysteroid dehydrogenase activity have been successfully solubilized from the microsomal membranes of both bovine and human adrenal glands using a combination of Triton X-100 and sonication. These moieties have been studied by gel filtration, sucrose density gradient centrifugation and isoelectric focusing, and were shown to possess a minimum molecular weight of about 118000, with an isoelectric point between 7·2 and 7·4. The molecular weight was dependent upon the concentration of Triton X-100 used during fractionation. No separation of dehydrogenase activities toward the three steroid substrates, pregnenolone, 17α-hydroxypregnenolone and dehydroisoandrosterone, was observed. Changes in the relative activities for the steroid substrates during fractionation were observed, but have been attributed to the formation of allotypes rather than to the existence of separate dehydrogenases with restricted substrate specificity.
SOME EXPERIMENTS ON THE ROLE OF THE FOETAL PITUITARY IN THE MATURATION OF THE FOETAL ADRENAL AND THE INDUCTION OF PARTURITION IN SHEEP
Authors: JONES C. T. , RITCHIE J. W. K. , FLINT A. P. F.
Published: December 2008

The effect of repeated increases in plasma ACTH on the production of corticosteroids and androstenedione in the sheep foetus has been investigated. Elevation of foetal plasma ACTH for up to 2 h every 24 h by repeated periods of hypoxia increased the output of cortisol. No consistent effects on foetal or maternal androstenedione concentrations or on maternal oestrogen levels were observed. Repeated short periods of increased foetal plasma ACTH concentration may promote maturation of the foetal adrenal, but there is no increase in androgen secretion by the gland nor is there an increase in oestrogen production by the placenta under such conditions.
THYROTROPHIN RELEASING HORMONE-INDUCED GROWTH HORMONE AND PROLACTIN RELEASE: PHYSIOLOGICAL STUDIES IN INTACT RATS AND IN HYPOPHYSECTOMIZED RATS BEARING AN ECTOPIC PITUITARY GLAND
Authors: PANERAI A. E. , GIL-AD IRIT , COCCHI DANIELA , LOCATELLI V. , ROSSI G. L. , MÜLLER E. E.
Published: December 2008

To determine how the sensitivity of the ectopic anterior pituitary gland to the GH-releasing effect of thyrotrophin releasing hormone (TRH) might be affected by the time lapse from transplantation, TRH (0·15 and 0·6 μg) was injected i.v. into hypophysectomized (hypox)-transplanted rats under urethane anaesthesia 1,3, 8,15, 30 and 60 days after transplantation, and plasma samples were taken 5 and 10 min later. Baseline GH values gradually decreased with time from about 16·0 ng/ml (1 day) to about 3·0 ng/ml (30 and 60 days). The TRH-induced GH release was absent 1 day after transplantation, present only with the higher TRH dose 3 and 8 days after transplantation, and clearly elicitable, also with the lower TRH dose (0·15 μg), from 15 up to 60 days. Determination of plasma prolactin concentrations showed a decline from about 85·0 ng/ml (1 day) to about 32·0 ng/ml (8 days); subsequently (15–60 days) prolactin values stabilized. Plasma prolactin levels increased 15 and 60 days after transplantation only when a dose of 0·6 μg TRH was given.

In intact weight-matched rats, TRH induced a GH response only at the dose of 1·2 μg while a short-lived but clear-cut prolactin response could be obtained even with the 0·3 μg dose.

The present results indicate that: (1) disconnexion between the central nervous system and the anterior pituitary gland greatly enhances GH responsiveness while blunting prolactin responsiveness to TRH; (2) the sensitivity of the anterior pituitary gland to the GH-releasing effect of TRH increases with time from transplantation; (3) TRH is a more effective prolactin-than GH-releaser on the pituitary gland in situ.
STEROID RELEASE IN VITRO BY TWO LUTEAL CELL TYPES IN THE CORPUS LUTEUM OF THE PREGNANT SOW
Authors: LEMON MEREDITH , LOIR M.
Published: December 2008

Corpora lutea from sows at 30, 60 and 90 days of gestation were dissociated enzymically, and the components of the resulting cell suspension were separated by sedimentation at unit gravity. Two luteal cell populations of 30–50 μm diameter and 15–20 μm diameter were obtained and superfused for up to 18 h with Dulbecco's modified Eagle medium, the cells being supported in a column in a matrix of Biogel. Fractions were collected every 30 min and assayed for progesterone and oestradiol-17β.

At 30 and 60 days of gestation the large luteal cells produced progesterone at an initial rate of approximately 100 ng/h/105 cells, which decreased to half this rate at 90 days. The smaller cells also released progesterone into the medium at approximately 15–20 ng/h/105 cells at all stages of gestation. At 30 days of gestation, neither cell type released significant amounts of oestradiol-17β, but from 60 days onwards, significant and increasing quantities were measured in the superfusates from the larger cells.

Both cell types were perfused with porcine LH at the three stages of gestation, and both showed an immediate response in terms of progesterone release which decreased in magnitude with increasing age of gestation. The response of the smaller cells was greater than that of the larger cells.
EFFECTS OF ANTERIOR HYPOTHALAMIC IMPLANTATION OF GONADAL STEROIDS ON SERUM AND PITUITARY GONADOTROPHINS (FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE) IN THE CASTRATED MALE RAT
Authors: DANGUY A. , ECTORS F. , PASTEELS J. L.
Published: December 2008

Castrated rats were stereotaxically implanted with 1 μg oestradiol benzoate, 5 μg testosterone isobutyrate or, as a control, 10 μg cholesterol, in the hypothalamus. The effects of the steroids on plasma and pituitary gonadotrophins (FSH and LH) were assessed by radioimmunoassay. Our results indicate that, in the male rat, in addition to the arcuate nucleus–median eminence complex, the preoptic suprachiasmatic area is able to control synthesis and secretion of both gonadotrophins, and that it is sensitive to oestradiol and testosterone.
USE OF A COMPETITIVE PROTEIN-BINDING ASSAY FOR ADENOSINE 3′:5′-PHOSPHATE FOR THE STUDY OF BOVINE CORPUS LUTEUM ADENYLATE CYCLASE
Authors: YOUNG J. L. , STANSFIELD D. A.
Published: December 2008

The use of a competitive protein-binding assay for cyclic AMP, utilizing the binding protein purified from bovine adrenal cortex, for the study of adenylate cyclase activity of the washed 600 g sediment of bovine corpus luteum is validated.

A specific assay for cyclic AMP could only be achieved by removal of the degradation products of ATP on a precipitate of nascent BaSO4. Simple dilution of the sample before assay was not sufficient to eliminate interference from degradation products of ATP.

An observed variability in optimal ATP substrate and tissue concentrations is thought to reflect variability in the enzymic profile of the cyclic corpus luteum. Optima with respect to F−, Mg2+ and pH are more clearly defined and are similar to those reported for adenylate cyclase systems of other tissues.
EXOGENOUS PROGESTERONE: INFLUENCE ON OVULATION AND HORMONE LEVELS IN THE CYCLIC HAMSTER
Authors: GREENWALD G. S.
Published: December 2008

The oestrous cycle of the hamster is lengthened by 2 to 3 days when 2·5 or 5·0 mg progesterone are injected on day 1 of the cycle (day of ovulation). Antral follicles develop on day 2 but their growth is significantly retarded in progesterone-treated hamsters. Administration of progesterone is followed within 6 h by an abrupt decline in serum FSH and LH concentration but by day 3 the level of FSH is higher than normal. Serum LH is slower to recover in hamsters receiving 5 mg progesterone but normal levels are also restored by days 3 or 4. Increased serum levels of progesterone are maintained until days 3–5 in animals injected with progesterone.

Despite the presence of antral follicles on day 2 and the fairly prompt restoration of normal levels of gonadotrophins, the serum concentration of oestradiol is suppressed for several days in the progesterone-treated hamster. This suggests that progesterone, in addition to affecting the hypothalamic-pituitary system, may also directly inhibit oestrogen secretion by the antral follicles.
STEROIDS AND PITUITARY RESPONSIVENESS IN FEMALE, ANDROGENIZED FEMALE AND MALE RATS
Authors: FINK G. , HENDERSON S. R.
Published: December 2008

Spontaneous gonadotrophin release and the gonadotrophin response to LH releasing factor (RF) were studied in pro-oestrous, androgenized female and male rats. The animals were either intact or gonadectomized (about 32 h previously) and treated with various steroids. The gonadotrophin response (especially LH) was much lower in intact males and androgenized females than in pro-oestrous females. Oestrogen plus progesterone increased plasma gonadotrophin concentrations and responses in ovariectomized rats, but inhibited the increase in the plasma gonadotrophin concentration and the LH response which followed castration in males. As in the normal female, ovariectomy decreased the LH response but increased the plasma FSH concentration and response in the androgenized female; oestrogen and progesterone had relatively little effect. Apart from reducing the postcastration rise in plasma FSH, testosterone had no significant effect in gonadectomized male or female animals. These results show that the effect of steroids on the gonadotrophin response to LH-RF as well as the spontaneous secretion of gonadotrophin depends upon sexual differentiation of the hypothalamo-hypophysial system. Studies with various metabolites of progesterone indicated that the facilitatory action of this steroid could be due, in part, to a 5α-reduced derivative.
HORMONAL EFFECTS OF TAMOXIFEN IN OLIGOSPERMIC MEN
Authors: WILLIS K. J. , LONDON D. R. , BEVIS M. A. , BUTT W. R. , LYNCH S. S. , HOLDER G.
Published: December 2008

The hormonal effects of tamoxifen (10 mg daily for 6 months) have been studied in nine men with oligospermia. Basal concentrations of serum LH (1·7 ± 0·1 (s.e.m.) i.u./l) increased to a maximum of 4·1 ± 1·3 i.u./l (P < 0·001) after 6 months, and FSH rose from 4·9 ± 1·0 to a maximum of 7·7 ± 1·3 i.u./l after 4 months of treatment (P < 0·01).

The response to luteinizing hormone releasing hormone (LH-RH) was studied at monthly intervals. Sums of increments of serum LH increased from 35 ± 4 to 92 ± 17 i.u./l at 4 months (P < 0·001) and of FSH from 14 ± 3·4 to 23 ± 3·5 i.u./l at 4 months (P < 0·01).

Basal serum androgens rose from 25 ± 2·7 to 38 ± 2·4 nmol/l after 4 months of treatment (P < 0·05), and serum oestradiol-17β increased from 185 ± 25 to 631 ± 90 pmol/l by 6 months (P < 0·001). No significant changes occurred in sperm counts.

Five normal men acted as controls: they were given tamoxifen for 1 week. No significant changes were observed in serum LH, FSH or release of these hormones following administration of LH-RH. Serum androgens and oestrogens however, increased significantly by day 4 of treatment (P < 0·05).
CAPRINE PLACENTAL LACTOGEN: LEVELS OF PROLACTIN-LIKE AND GROWTH HORMONE-LIKE ACTIVITIES IN THE CIRCULATION OF PREGNANT GOATS DETERMINED BY RADIORECEPTOR ASSAYS
Authors: CURRIE W. B. , KELLY P. A. , FRIESEN H. G. , THORBURN G. D.
Published: December 2008

Radioreceptor assays for prolactin-like (lactogenic) activity and growth hormone (GH)-like activity have been used to study concentrations of caprine placental lactogen (PL) in the circulation during pregnancy. Both lactogenic and GH-like activities increased from less than 100 ng/ml (ovine prolactin- and human GH-equivalents) about 60 days after mating to reach peak levels (400–1600 ng/ml) between days 110 and 130 of pregnancy. The levels of both activities increased in essentially the same fashion but during the last 15 days of pregnancy, lactogenic activity declined less than GH-like activity. This divergence was most pronounced at parturition when levels of lactogenic activity increased (∼ 700 ng/ml) despite very low (< 200 ng/ml) levels of GH-like activity being measured and this probably reflected increased secretion of pituitary prolactin near parturition. When serum from a pregnant goat or a simple alkaline extract of placental cotyledons was fractionated on a column packed with Sephadex G-100, lactogenic and GH-like activities eluted together with distribution coefficients of approximately 0·5–0·6. The possibility that caprine PL serves physiologically as a luteotrophin and/or mammotrophin during pregnancy in goats is discussed.
STEROID SEX HORMONES AND PROLACTIN IN POSTMENOPAUSAL WOMEN WITH GENERALIZED MAMMARY CARCINOMA DURING PROLONGED DEXAMETHASONE TREATMENT
Authors: BORKOWSKI A. , L'HERMITE M. , DOR P. , LONGEVAL E. , ROZENCWEIG M. , MUQUARDT C. , VAN CAUTER E.
Published: December 2008

The endocrine response to prolonged dexamethasones treatment was investigated in six postmenopausal women with generalized mammary carcinoma. Plasma cortisol levels decreased rapidly and became undetectable whereas significant concentrations of plasma dehydroepiandrosterone and androstenedione persist throughout the study, even in two ovariectomized patients, indicating a certain degree of autonomy or a greater resistance of adrenal 'androgens' to the inhibition of ACTH secretion.

Except in the ovariectomized patients, plasma testosterone did not fall significantly whereas the plasma oestrogens tended progressively towards undetectable concentrations. A similar response was found in six normal postmenopausal women although the disappearance of their oestrogens was relatively rapid. This indicates that much of the testosterone patient after the menopause could still be produced by the ovaries whereas the ovarian production of oestrogens becomes negligible. The delayed disappearance of oestrogens in the patients with mammary carcinoma indicates that the persisting adrenal 'androgens' remained efficient precursors of oestrogen synthesis within the peripheral tissues and presumably within the mammary tumour itself. Plasma dihydrotestosterone behaved like the plasma oestrogens. Despite the fall in plasma oestrogens, plasma gonadotrophins did not increase further but plasma prolactin rose progressively.

The persistence of steroid sex hormones and the rise of plasma prolactin might explain the poor response to dexamethasone treatment in mammary carcinoma.
PROLACTIN AND LUTEINIZING HORMONE LEVELS BEFORE AND AFTER PARTURITION IN RATS BEARING EITHER SINGLE OR MULTIPLE EMBRYOS
Authors: NIR I. , GOLDHABER G. , HIRSCHMANN N. , SHANI J.
Published: December 2008

Levels of prolactin and LH were determined in serum and pituitary during the last days of pregnancy and post partum in rats bearing single and multiple embryos. In rats with a single embryo serum prolactin and LH levels were significantly lower during the last 2 days of pregnancy and post partum than in rats bearing multiple embryos. While large increases were recorded in serum prolactin and LH levels in the rats with multiple embryos between days 21 and 22 of gestation, in the group with single embryos changes occurred in LH level only. Throughout the experiment pituitary prolactin was lower in rats with a single embryo than in those with multiple embryos in spite of the sharp drop in prolactin level in the group with multiple embryos from day 21 to 22. No differences were observed in the pituitary LH levels of either group during the days preceding parturition, but in the rats with multiple embryos there was a sharp drop in LH level post partum. It seems that the reduced serum prolactin level in the rats with a single embryo was associated with inhibition of pituitary prolactin synthesis and release, whereas the decreased serum LH level resulted from impaired release but not synthesis. These results support the hypothesis of a regulatory role for the placenta in pituitary prolactin and LH synthesis and release, either by hypothalamus– pituitary stimulation, or perhaps by way of the ovaries, through regulation of ovarian steroid production.
ENDOCRINE REGULATION OF SEX-DEPENDENT HYDROXYSTEROID DEHYDROGENASE ACTIVITIES IN RAT KIDNEY: NADP-DEPENDENT MICROSOMAL 3α- AND 20β-HYDROXYSTEROID DEHYDROGENASE
Authors: GHRAF R. , LAX E. R. , WAGNER W. , SCHRIEFERS H.
Published: December 2008

The NADP-dependent microsomal kidney enzymes, 3α- and 20β-hydroxysteroid dehydrogenase (HSDH), which exhibit considerable sex differences in their activities (male: female activity ratios, 16:1 and 30:1 respectively), were investigated after interference with the pituitary–gonad and pituitary–adrenal systems.

Prepubertal gonadectomy as well as hypophysectomy of mature male rats led to a decline in HSDH activity to almost that found in the normal female rat, whereas activities in female rats were unaffected. Testosterone induced typical male 3α-HSDH activity in both gonadectomized and hypophysectomized rats of either sex. Administration of 5α-dihydrotestosterone (5α-DHT) or 5α-androstane-3α, 17β-diol to hypophysectomized male rats was equally effective in restoring full 3α- and 20β-HSDH activities whereas 5α-androstane-3β, 17β-diol was less effective and dehydroepiandrosterone was ineffective. Simultaneous administration of cyproterone acetate did not block the inductive action of 5α-DHT.

Administration of chorionic gonadotrophin, pregnant mare serum gonadotrophin or a combination of luteinizing hormone and follicle-stimulating hormone to hypophysectomized male rats all led to parallel increases in the weight of the seminal vesicles and in both renal enzyme activities; administration of growth hormone, prolactin or thyroid-stimulating hormone was ineffective.

Adrenalectomy of gonadectomized, but not of hypophysectomized male rats, caused a further drop in activity to the normal female level. Adrenalectomy of otherwise intact rats did not affect either enzyme activity.

The hypophysis was involved in the regulation of the two NADP-dependent renal HSDH activities through its gonadotrophic function in male rats; adrenal secretions were of little physiological significance.
INFLUENCE OF FOETAL GENOTYPE ON THE FOLLICLE-STIMULATING HORMONE:LUTEINIZING HORMONE RATIO OF PREGNANT MARE SERUM GONADOTROPHIN
Authors: STEWART FRANCESCA , ALLEN W. R. , MOOR R. M.
Published: December 2008

Rat testicular radioreceptor assays specific for FSH and LH were used to determine the FSH: LH ratio of PMSG produced by horse, donkey, mule and hinny conceptuses. Measurements of FSH and LH activities in PMSG produced both in vivo and in vitro by the four types of conceptuses showed that the genotype of the foetus markedly influences the FSH: LH ratio of PMSG. The FSH: LH ratio of PMSG produced by the horse conceptus was around unity whereas the ratio of PMSG produced by the donkey conceptus was as low as 0·2. Furthermore, the hybrid mule and hinny conceptuses both produced PMSG with an FSH: LH ratio which was approximately midway between those of the horse and donkey.