bluuebunny/crossref_metadata_2025 huggingface dataset:
PROTEIN-BOUND CYCLIC AMP AND STEROIDOGENESIS IN THE ADRENAL GLAND OF THE RAT
Authors: GUILLEMANT J. , GUILLEMANT S.
Published: December 2008

Adrenocortical cyclic AMP (both total and protein-bound), and adrenal and plasma concentrations of corticosterone were measured in male rats killed at selected intervals throughout the day. The animals had previously been synchronized for 3 weeks in natural lighting. Adrenal and plasma levels of corticosterone showed similar circadian fluctuations and the onset of their ascending phases started at 13.00 h, maximum concentrations being reached at 21.00 h. On the other hand, a time-lag between the circadian variations of total cyclic AMP and protein-bound cyclic AMP could be seen in adrenocortical tissue. The onset of an increase in adrenocortical protein-bound cyclic AMP was apparent at 15.00 h and the peak occurred at 21.00 h, while total adrenocortical cyclic AMP did not begin to rise before 19.00 h and was maximal at 04.00 h. No direct link between total cyclic AMP and protein-bound cyclic AMP could be seen during the dark phase, suggesting a functional compartmentalization of cyclic AMP in the adrenal gland of the rat. While the ascending phase of the rhythm in steroidogenesis preceded the rise in total adrenocortical cyclic AMP by about 4 h an excellent synchrony between the respective patterns of corticosterone concentration and protein-bound cyclic AMP was noticed.
IN-VITRO METABOLISM OF 4-ANDROSTENE-3,17-DIONE BY HEPATIC MICROSOMES FROM THE RAINBOW TROUT (SALMO GAIRDNERII): EFFECTS OF HYPOPHYSECTOMY AND OESTRADIOL-17β
Authors: HANSSON TIIU , GUSTAFSSON JAN-ÅKE
Published: December 2008

The metabolism of 4-androstene-3,17-dione by liver microsomes from juvenile rainbow trout, Salmo gairdnerii, was studied in vitro. Hypophysectomy of the fish significantly increased mean hepatic 17-hydroxysteroid oxidoreductase activity when compared with that from sham-operated fish but none of the other enzyme activities investigated were affected. Administration of oestradiol-17β resulted in a significant decrease in mean hepatic 6β-hydroxylase activity and total cytochrome P-450 content but had no effect on the 16-hydroxylation or on the reductive metabolism of androstenedione. The effect of oestradiol-17β on hepatic 6β-hydroxylase activity was as pronounced after hypophysectomy as after sham-operation indicating that these effects of oestradiol-17β are mainly direct and independent of the pituitary gland. The results indicate that hypophysial hormone(s) as well as oestradiol-17β play a role in the regulation of hepatic steroid metabolism in trout.
FOLLICLE FORMATION AND IODIDE METABOLISM IN CULTURES OF HUMAN THYROID CELLS
Authors: DICKSON J. G. , HOVSÉPIAN S. , FAYET G. , LISSITZKY S.
Published: December 2008

Primary cultures were initiated using thyroid tissue obtained at operation from patients with Graves's disease. The in-vitro conditions which permitted the formation of functional follicular structures in both primary cultures and derived sub-cultures were examined. In both situations, culture without the addition of calf serum to the medium resulted in the formation of follicles in response to thyrotrophin. In primary cultures the response to stimulation by exogenous thyrotrophin was variable. However, cells derived from long-term primary monolayers responded to thyrotrophin stimulation in a more predictable manner.

In sub-cultures, the ability of cells to concentrate and organify iodide was augmented in a dose-dependent fashion in response to thyrotrophin (0 to 0·2 mu./ml); maximal values of 20 to 80 times those of control cultures being obtained. While follicular structure was maintained at higher hormone concentrations, iodide-trapping capacity declined. Similar effects were produced by both low and high purity thyrotrophin and by dibutyryl cyclic AMP.

Thyroid cells from two patients with a genetic defect of iodide organification exhibited the same lesion in vitro.
DISTRIBUTION AND CONCENTRATIONS OF ANDROGENS IN EPITHELIAL AND STROMAL COMPARTMENTS OF THE HUMAN BENIGN HYPERTROPHIC PROSTATE
Authors: BOLTON N. J. , LAHTONEN RIITTA , HAMMOND G. L. , VIHKO R.
Published: December 2008

Prostate tissues removed from patients with benign prostatic hypertrophy were separated into epithelial and stromal components and the concentrations of testosterone, 5α-dihydrotestosterone, 5α-androstane-3α,17β-diol, 4-androstene-3,17-dione, 5α-androstanedione stanedione and androsterone in these two fractions were determined by radioimmunoassays after the purification of solvent steroid extracts by Lipidex-5000 column chromatography. On a 'per cell' basis (i.e. relative to DNA), testosterone was equally distributed between the two components, while the other androgens measured were more abundant in the stroma. The observation that 5α-reduced androgens (especially 5α-dihydrotestosterone) were more concentrated in the stroma, and that significant correlations between concentrations of metabolically related androgens were more common in the stroma than in the epithelium, indicate that the stroma is an important site of androgen metabolism in benign prostatic hypertrophic tissues. The present data also support the suggestion that 5α-dihydrotestosterone produced in the prostatic stroma may be transferred to the epithelium by way of sex hormone binding globulin in the extracellular spaces of the prostate.
PROLACTIN IN MAINTENANCE OF THE CORPUS LUTEUM OF EARLY PSEUDOPREGNANCY IN THE GOLDEN HAMSTER
Authors: HARRIS K. H. , MURPHY B. D.
Published: December 2008

The role of prolactin in the maintenance of the corpus luteum of pseudopregnancy was studied in the golden hamster. Nine groups of seven to fourteen animals each received 1 mg bromocriptine at 11.00 h on days 1, 2 or 3 of pseudopregnancy (three groups for each day). On each day of treatment with bromocriptine, one group of hamsters was injected with bovine prolactin 4 h before bromocriptine, and one group received prolactin 4 h before bromocriptine for three consecutive days following treatment with bromocriptine. One group received bromocriptine only. These nine groups were compared with a control group of animals given 0·85% saline instead of bromocriptine and prolactin. Peripheral blood samples were taken from all hamsters at 11.00 h on days 3, 4, 5 and 6 of pseudopregnancy and plasma levels of progesterone were determined by radioimmunoassay. Luteolysis, indicated by a decline in progesterone level by 24 or 48 h after treatment with bromocriptine, occurred in all hamsters given bromocriptine alone, whether it was administered on day 1, 2 or 3. Pretreatment with a single dose of prolactin did not mitigate the bromocriptine-induced fall in progesterone. In the majority of cases, pretreatment with prolactin plus daily doses of prolactin maintained the progesterone at levels not different from saline-treated hamsters. These data suggest that prolactin is a necessary luteotrophin during early pseudopregnancy without which luteolysis ensues.
ONTOGENESIS OF THE ADRENAL GLUCOCORTICOIDS AND OF THE TARGET FUNCTION OF THE ENZYMATIC TYROSINE TRANSAMINASE ACTIVITY IN THE CHICK EMBRYO
Authors: MARIE C.
Published: December 2008

Adrenal and plasma glucocorticoids were determined in developing chick embryos of Gallus domesticus from days 8 to 19 of incubation, using a competitive protein-binding assay. At the same time, tyrosine transaminase activity in the liver was studied as an adrenal-dependent target function.

Total amounts of glucocorticoids in the adrenal gland increased from day 11 and reached 7 ng/pair of glands on day 19. This increase was related to growth of the adrenal since concentrations remained constant at about 380 pg/μg dry weight from days 9 to 18. Glucocorticoids appeared in the plasma on day 12 and their concentrations rose to 10 ng/ml on day 19, with a marked peak on day 13. This peak was not reflected in the tyrosine transaminase activity which appeared and developed independently of the variations in the circulating glucocorticoids.
EFFECT OF CORTISOL AND DEXAMETHASONE ON THE OESTROGEN-INDUCED RELEASE OF LUTEINIZING HORMONE IN THE ANOESTROUS EWE
Authors: MOBERG G. P. , WATSON J. G. , STOEBEL D. P. , COOK R.
Published: December 2008

The oestrogen-induced release of LH in anoestrous ewes was used as a model for studying the effect that glucocorticoids have on the secretion of LH. It was found that neither the repeated administration of the synthetic glucocorticoid, dexamethasone, nor the infusion of cortisol blocked the oestrogen-induced release of LH in the anoestrous ewe. These findings indicate that, in the ewe, glucocorticoids do not alter the ability of oestrogen to induce LH secretion.
EFFECTS OF OESTRADIOL, HYPOTHALAMIC EXTRACTS AND LUTEINIZING HORMONE RELEASING HORMONE ON RAT ANTERIOR PITUITARY GLAND GONADOTROPHIN RELEASE IN VITRO BEFORE AND AFTER THE PREOVULATORY LUTEINIZING HORMONE SURGE AT PRO-OESTRUS
Authors: ELIAS KATHLEEN A. , BLAKE C. A.
Published: December 2008

Changes at the anterior pituitary and/or hypothalamic levels which result in selective FSH release during late pro-oestrus in the cyclic rat were investigated. The possible involvement of decreasing serum concentrations of oestrogen during pro-oestrus in such changes was studied. Rats were decapitated at 12.00 h on pro-oestrus, before the onset of the LH surge and first phase of FSH release, or at 24.00 h on pro-oestrus, shortly after the onset of the second or selective phase of FSH release. Other rats were given oestrogen (OE2) at 14.00 h and killed at 24.00 h pro-oestrus. Paired hemi-anterior pituitary glands were incubated with vehicle or OE2 with or without synthetic LH-releasing hormone (LH-RH) or hypothalamic acid extracts prepared from rats killed at 12.00 or 24.00 h on pro-oestrus. At 24.00 h pro-oestrus, serum FSH concentration was high while serum LH concentration was low regardless of whether rats were given OE2. Glands collected and incubated at 24.00 h released more FSH and less LH than did glands collected and incubated at 12.00 h pro-oestrus. Administration of OE2 in vivo and/or in vitro did not affect these responses. The increments in LH and FSH release attributed to LH-RH or hypothalamic extracts in the glands incubated at 24.00 h were not different from those of the glands incubated at 12.00 h. Also, the hypothalamic extracts prepared from rats killed at 24.00 h were no more effective than the extracts prepared from rats killed at 12.00 h in releasing LH or FSH from glands incubated at 12.00 or 24.00 h pro-oestrus. Administration of OE2 in vivo caused a small suppression of LH-RH-induced FSH release. We suggest that a change occurs at the level of the anterior pituitary gland during the period of the LH surge and first phase of FSH release to increase basal FSH secretion selectively and cause, at least in part, the second phase of increased serum FSH. This change is not mediated by a decrease in serum oestrogen concentration. We failed to observe any evidence that LH-RH causes preferential FSH release during late pro-oestrus or that a hypothalamic peptide with a preferential FSH releasing ability is involved in FSH release at this time.
TESTICULAR FUNCTION IN STRAINS OF MICE SELECTED FOR DIFFERENCES IN GONADOTROPHIN-INDUCED OVULATION RATE
Authors: WOLFE H. G. , BARTKE A. , AMADOR A. , VAN SICKLE MARY , DALTERIO SUSAN , BROWN D.
Published: December 2008

Mice were selected on the basis of ovulatory responses to injections of pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG). Various parameters of pituitary and gonadal function as well as responsiveness to exogenous gonadotrophins were examined in males from high induced-ovulation rate (HIOV) and low induced-ovulation rate (LIOV) lines. Testicular weight, seminal vesicle weight and plasma LH levels were lower in HIOV than in LIOV males, while plasma concentrations of FSH and testosterone did not differ. Binding of FSH, but not of LH, in the testes was significantly higher in HIOV mice. Twenty-four hours after administration of hCG, plasma testosterone levels were higher and testicular LH binding sites appeared more depleted in HIOV than in LIOV males. Production of testosterone by decapsulated testes in vitro was significantly higher in HIOV than in LIOV mice under basal conditions, as well as in the presence of LH, FSH, hCG or PMSG. It was concluded that selection for differences in gonadotrophin-induced ovulation rate produced correlated differences in the steroidogenic response of the testes to gonadotrophins and that these differences may be due to divergence in the number of gonadal FSH binding sites.
EFFECT OF GLUCOCORTICOIDS, BUTANOL EXTRACTION OF SERUM AND ADRENALECTOMY ON SOMATOMEDIN LEVELS IN THE RAT
Authors: HOLDER A. T. , PREECE M. A. , WALLIS M.
Published: December 2008

Serum from adrenalectomized rats was equipotent with serum from non-adrenalectomized animals when measured in a rat cartilage somatomedin bioassay. Extraction with butanol of sera from normal or adrenalectomized rats reduced their potency in the somatomedin bioassay rather than increasing it as has been previously reported. Butanol-soluble inhibitors of cartilage metabolism were found in sera from both normal and adrenalectomized rats. Cortisol and corticosterone, up to mildly supraphysiological levels, were found to have no effect on basal cartilage metabolism. These results suggest that physiological levels of glucocorticoids do not exert an inhibitory effect on the uptake of 35SO42− into immature rat cartilage. Since butanol-soluble inhibitors of cartilage metabolism were found in adrenalectomized rat serum it is unlikely that these substances are glucocorticoids.
CHANGES IN PLASMA LEVELS OF CALCIUM AND IN BONE MARROW MITOSIS AFTER ANTIGENIC CHALLENGE IN RATS AND MICE
Authors: EDWARDS D. J. , RIMMER J. J. , ATKINSON M. J. , PERRIS A. D.
Published: December 2008

When rats or mice were immunized with sheep red blood cells, bacterial lipopolysaccharides or bovine serum albumin, a proliferative response could be detected in the bone marrow and spleen. This response was associated with a hypercalcaemic phase. Parathyroidectomy, which resulted in a protracted hypocalcaemia, prevented the development of an increase in levels of plasma calcium. This operation also prevented the rise in bone marrow proliferation following antigenic challenge, but did not ablate the normal proliferative response to antigen by cells in the spleen. Antibody production and numbers of antibody-forming cells were not significantly reduced by parathyroidectomy. These results suggest that there is a pool of antigen-insensitive cells in the bone marrow which are stimulated after antigenic challenge. It is postulated that these events are mediated by the development of a parathyroid-dependent hypercalcaemia which stimulates the cells non-specifically. These events may form part of a cellular homeostasis, replacing cells in peripheral lymphoid tissues.
CHANGES IN THE PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, PROGESTERONE, OESTRADIOL AND TESTOSTERONE AND IN THE BINDING OF FOLLICLE-STIMULATING HORMONE TO THE THECA OF FOLLICLES DURING THE OVULATION CYCLE OF THE HEN (GALLUS DOMESTICUS)
Authors: ETCHES R. J. , CHENG K. W.
Published: December 2008

The changes in the binding of FSH during follicular maturation were examined in the hen using 125I-labelled bovine FSH (bFSH) and unlabelled bFSH. The binding of 125I-labelled bFSH was not inhibited by bovine LH or chicken LH but was inhibited by extracts of chicken pituitary glands. The ovarian stroma, which contained both interstitial tissue and small follicles, bound the greatest amount of FSH. As the follicles progressed through the yolk-filled hierarchy of maturation, they bound decreasing amounts of FSH. In the two largest follicles of the hierarchy, there was a significant increase in the binding of FSH 12–16 h before ovulation. There were two peaks in the concentrations of LH; a preovulatory peak occurred 4–6 h before ovulation and a second peak occurred 14–16 h before ovulation. Plasma concentrations of testosterone, oestradiol and progesterone began to rise 9, 8 and 6 h, respectively, before ovulation. These data are consistent with the hypothesis that changes in the gonadotrophin concentration and binding regulate the order of the follicular hierarchy and the onset of preovulatory steroidogenesis in the hen.
AGE-RELATED CHANGES IN THE METABOLISM OF [3H]TESTOSTERONE IN VITRO BY THE EPIDIDYMIS OF THE IMMATURE RAT
Authors: FOLDESY R. G. , LEATHEM J. H.
Published: December 2008

We examined the production in vitro of 5α-reduced metabolites from testosterone by the rat epididymis during pubertal maturation. Minced caput and cauda epididymides from 30-, 45-, and 55-day-old rats were incubated with [3H]testosterone for 2 h. Analysis of the radioactive metabolites revealed both similarities and differences in the metabolic patterns compared to those reported for adult rats. As in adults, 5α-dihydrotestosterone was the most abundant metabolite produced by both epididymal segments at all three ages, and it was formed in larger quantities in the caput epididymidis than in the cauda. However, [3H]testosterone metabolism by the epididymis of the immature rat was characterized by a lower formation of 5α-androstane-3α,17β-diol and higher production of 5α-androstane-3,17-dione than in adults. Production of these two metabolites by the caput region increased and decreased respectively, toward adult levels, with increasing age. In addition, the amount of [3H]testosterone metabolized was higher with tissues from prepubertal rats (30 days of age) than with those from rats 55 days of age. These data suggest that testosterone metabolism in the caput begins to change to that of the adult during the period of pubertal maturation but apparently not until later in the cauda epididymidis.
STIMULATION BY POLYPEPTIDES OF DEHYDROEPIANDROSTERONE SULPHATE SYNTHESIS IN HUMAN FETAL ADRENAL SLICES
Authors: BROWN T. J. , GINZ BERYL , MILNE CATHERINE M. , OAKEY R. E.
Published: December 2008

Slices of human fetal adrenal glands (obtained after abortion at 10–18 weeks of gestation) were superfused sequentially with buffer or with buffer incorporating human ACTH, synthetic ACTH(1–24), human GH, human chorionic gonadotrophin, α-melanocyte stimulating hormone, metenkephalin, ovine prolactin, β-lipotrophic hormone or corticotrophin-like intermediate lobe peptide in concentrations from 10−6 to 10−9 mol/l. Changes in the concentration of dehydroepiandrosterone sulphate (DHAS) in the effluent in response to addition or removal of the polypeptides were measured by radioimmunoassay. Comparison of the quantity of DHAS in the effluent collected during superfusion (5 h) with that present in the tissue initially indicated that synthesis of this conjugated steroid occurred during superfusion.

Increases in the concentration of DHAS in the effluent were provoked by exposure of the tissue to all the polypeptides except corticotrophin-like intermediate lobe peptide.

These effects were unlikely to be non-specific since incorporation of gonadotrophins, albumin or dextran into the superfusate did not stimulate corticosteroid synthesis from viable bovine adrenal tissue.

It was concluded that a number of pituitary polypeptides have the potential to provoke androgen sulphate synthesis by the human fetal gland in early gestation. Consequently there may be no single fetal corticotrophin at this stage and androgen production may be regulated by a number of trophic factors.
CONTROL OF STEROIDOGENESIS IN RAT CORPUS LUTEUM: THE RATE OF ACCESS OF CHOLESTEROL TO THE ACTIVE SITE OF THE CHOLESTEROL SIDE-CHAIN CLEAVAGE ENZYME
Authors: LEAVER H. A. , BOYD G. S.
Published: December 2008

The pool of cholesterol at the active site of the cholesterol side-chain cleavage enzyme was increased by preincubation with substrate. This process occurred at a linear time-dependent rate over 20 min, whereas uptake of cholesterol into mitochondria was complete by 1 min. Both endogenous mitochondrial cholesterol and added extramitochondrial cholesterol showed similar time-dependent substrate preincubation kinetics. The rate of metabolism of exogenous cholesterol was increased by injection of LH and decreased by treatment with cycloheximide. The rate of entry of cholesterol into the active site in both preparations, however, retained linear time-dependent kinetics. Calcium ions (2 mmol/l) increased the rate of steroidogenesis most in mitochondria preincubated for short periods and least in mitochondria preincubated for longer periods. These studies indicated that the pool of cholesterol at the active site of the enzyme can determine the rate of pregnenolone biosynthesis in the mitochondria of rat corpus luteum. Calcium ions, but not trophic hormones or cycloheximide, appeared to alter the access of cholesterol to the active site of the cholesterol side-chain cleavage enzyme during substrate preincubation.
STIMULATION BY HUMAN CHORIONIC GONADOTROPHIN OF OESTRADIOL PRODUCTION BY DISPERSED CELLS FROM HUMAN CORPUS LUTEUM: COMPARISON WITH PROGESTERONE PRODUCTION; UTILIZATION OF EXOGENOUS TESTOSTERONE
Authors: RICHARDSON M. C. , MASSON G. M.
Published: December 2008

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared with two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared from mid- and late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (1 μmol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.
DOPAMINERGIC MODULATION OF ALDOSTERONE SECRETION?
Authors: McDOUGALL J. G. , SCOGGINS B. A. , BUTKUS ALDONA , COGHLAN J. P. , DENTON D. A. , FEI D. T. , HARDY K. J. , WRIGHT R. D.
Published: December 2008

Metoclopramide (10 mg i.v. injection followed by 10 mg/h i.v. for 2 h) caused a transient rise in blood concentrations of aldosterone in sodium-replete and sodium-depleted sheep. Infusion of metoclopramide into the adrenal artery of sheep with an autotransplanted adrenal gland, at a rate to give a similar concentration of metoclopramide at the adrenal cell level (calculated from rate of infusion and adrenal blood flow), resulted in no alteration in aldosterone secretion rate in either sodium-replete or sodium-depleted animals, even though intravenous metoclopramide caused transient stimulation of aldosterone secretion in the same sheep when sodium replete.

Dopamine administered either into the adrenal arterial blood supply or intravenously had no significant effect on aldosterone secretion and did not reverse the stimulatory effects of angiotensin II on aldosterone secretion in the adrenal transplant.

The data do not support the suggestion that direct dopaminergic elements play a tonic inhibitory role in aldosterone secretion. It is possible that the agonist effect of metoclopramide on aldosterone secretion may occur by some non-dopaminergic mechanism and it is tempting to speculate that the effect is centrally mediated.
PITUITARY CONTROL OF BLOOD COAGULATION IN THE RAT
Authors: KITA ETSUKO , LAMARTINIERE CORAL A.
Published: December 2008

Assay of prothrombin time, activated partial thromboplastin time and activity in the thrombotest in the rat showed that at 14 days of age, male and female rats had similar activities but female rats of 21–84 days of age had higher blood coagulation activities than male rats. Coagulation in mature female animals was not affected by the stage of the oestrous cycle. Hypophysectomy of prepubertal (21 days old) or adult (56 days old) male or female animals resulted in lower activity (prolongation of clotting time). A pituitary gland implanted ectopically under the kidney capsule of hypophysectomized animals resulted in shorter clotting times than in hypophysectomized animals not so treated. Pituitary glands from female donors were more effective in recipients of both sexes than those from males. These results demonstrate a sexual differentiation in activity of coagulation factors in the rat and suggest the involvement of the hypothalamic–hypophysial–gonadal axis in the regulation of blood coagulation.
SUPPRESSION OF LUTEINIZING HORMONE INDUCED BY ADRENOCORTICOTROPHIN IN HEALTHY WOMEN
Authors: VIERHAPPER H. , WALDHÄUSL W. , NOWOTNY P.
Published: December 2008

The effect of ACTH on serum concentrations of LH and FSH was studied in six healthy women in the follicular phase of the menstrual cycle, in six healthy men and in six patients (five men, one woman) with adrenocortical insufficiency. In healthy women the i.v. administration of synthetic 1–24 ACTH (0·25 mg) induced a fall in serum concentrations of LH from 11·1 ± 1·2 (s.d.) to 7·8 ± 0·6 i.u./l (P < 0·005) after 30 min and to 8·2 ± 0·7 i.u./l after 60 min. Upon continuous infusion of 1–24 ACTH (0·25 mg i.v., t = 480 min) LH fell to 6·7 ± 0·9 i.u./l (P < 0·005) in healthy women and to 6·1 ± 3·7 i.u./l (basal, 8·7 ± 3·9 i.u./l) in healthy men. In patients with adrenocortical insufficiency serum concentrations of LH were unchanged by 1–24 ACTH. Serum concentrations of FSH were not altered by 1–24 ACTH in any of the three groups. It is suggested that the effect of ACTH on LH secretion in healthy women is mediated by the acute rise of endogenous cortisol concentrations.
DECAPEPTIDE LUTEINIZING HORMONE RELEASING HORMONE IN OVINE PINEAL GLAND
Authors: KING JUDY A. , MILLAR R. P.
Published: December 2008

Ovine pineal gland extracts were examined throughout the year for content and molecular form of immunoreactive (IMR) LH releasing hormone (LH-RH). The content of IMR LH-RH in pineal glands collected in spring and summer was 160–2230 pg/gland, while the content in pineal glands collected in autumn and winter was lower (31–39 pg/gland). Pineal gland IMR LH-RH, purified by affinity and Sephadex G-25 chromatography, yielded displacement curves parallel to those of hypothalamic IMR LH-RH and synthetic LH-RH in radioimmunoassays employing four antisera which require different regions of the decapeptide for effective binding, suggesting considerable similarities in the structure of the molecule. The majority of pineal gland IMR LH-RH behaved identically to hypothalamic IMR LH-RH and synthetic LH-RH on gel filtration, cation exchange chromatography, high-pressure liquid chromatography and cellulose thin-layer chromatography. However, a small amount of a less positively charged LH-RH species was also present in all pineal gland extracts. Our findings indicate that hypothalamic decapeptide LH-RH occurs in the ovine pineal gland.
GROWTH HORMONE RELEASING ACTIVITY PERSISTS IN THE DEAFFERENTED MEDIAL-BASAL HYPOTHALAMUS OF THE RAT
Authors: ANTONI F. A. , MAKARA G. B. , RAPPAY GY.
Published: December 2008

The possible role of the neural connections of the medial-basal hypothalamus (MBH) in the maintenance of GH releasing activity of the pituitary stalk median eminence (SME) was investigated. Male rats, subjected to sham-operation and to complete and anterolateral cuts around the MBH were used 7–8 days after surgery. Electrical stimulation of neural structures within the MBH caused an increase of plasma GH in pentobarbitone- as well as in urethane-anaesthetized animals. In sham-operated rats the rise of plasma GH levels was apparent only after completion of 10 min of electrical stimulation, while in animals with complete or anterolateral cuts an increase was already evident during electrical stimulation. The results suggest that depolarization of somatostatin secreting fibres in the median eminence may be responsible for the delay in the rise of GH levels in sham-operated rats, while the increment can be attributed to a GH releasing principle in the hypothalamus. Acidic extracts of the SME of rats with complete or anterolateral cuts stimulated the release of GH by primary cultures of rat anterior pituitary cells. Microinjection of 0·05 SME equivalents of SME extract into the anterior pituitary gland of urethane-anaesthetized rats produced a rise in plasma GH levels within 3 min of injection. These data favour the existence of a GH releasing factor, and suggest that the ventromedial and arcuate hypothalamic nuclei are major sites of production of this releasing hormone.
STEROIDOGENIC AND GLYCOLYTIC RESPONSES TO NUCLEOTIDES, NUCLEOSIDES AND STEROIDS IN RODENT ADRENAL GLANDS: OPPOSING, SPECIES-DEPENDENT EFFECTS OF CYCLIC GMP
Authors: HUM W.-T. , BARTA-BARTOVA A. , BIRMINGHAM M. K.
Published: December 2008

The effects of nucleotides and nucleosides on steroidogenesis and aerobic lactic-acid production were examined in unsectioned mouse adrenal glands preincubated for 1 h and then incubated for 2 h in Krebs–Ringer bicarbonate and 0·01 m-glucose medium equilibrated with 95% O2:5% CO2. Of all the compounds tested, at a concentration of 10 mmol/l (cyclic AMP, cyclic GMP, AMP, ADP, ATP, GMP, IMP, adenosine, guanosine and inosine), only cyclic AMP was capable of stimulating steroidogenesis and induced a nine- to 12-fold increase in corticosterone production. Cyclic GMP inhibited corticosterone production by 40–55%. The nucleotides and nucleosides, except for ATP, all increased lactic-acid production. Cyclic AMP caused a three- to fivefold stimulation, cyclic GMP an increase of only 20–30%, and GMP, AMP and ADP increases of 80–100%. Cyclic GMP, protected from hydrolysis, may thus inhibit lactic-acid as well as steroid production in the mouse adrenal gland. By contrast, cyclic GMP was nearly as effective as cyclic AMP in stimulating glycolysis and steroidogenesis of rat adrenal glands. The proportion of corticosterone to 18-hydroxydeoxycorticosterone (18-OH-DOC) obtained with cyclic GMP was, however, always lower than that obtained with cyclic AMP. Cyclic AMP, as opposed to cyclic GMP, increased the formation of corticosterone and lactic acid in the presence of exogenous deoxycorticosterone (DOC) beyond that expected from an additive response. Lactic-acid production was inhibited by 18-OH-DOC, a major secretory product of the rat but not the mouse adrenal. This steroid, furthermore, greatly reduced the stimulation of glycolysis evoked by added DOC, 11β-hydroxyprogesterone and corticosterone, facts that could account for the greater glycolytic activity of mouse compared with rat adrenals. The yield of corticosterone in the presence of added 11β-hydroxyprogesterone, but not of DOC, was also reduced by 18-OH-DOC, denoting a selective inhibition of 21-hydroxylation. A structural analogue of 18-OH-DOC, 18,20-cyclo-20,21-dihydroxypregn-4-en-3-one, added by itself stimulated lactic-acid production. Added in combination with other steroids, it specifically counteracted the inhibitory effect of 18-OH-DOC, a steroid of potentially adverse biological properties. Our results are compatible with the concept that adrenal aerobic glycolysis is to a significant extent, but not exclusively, steroid-mediated. The glycolytically active but steroidogenically inert nucleotides and nucleosides offer examples of a dissociation between the two events.
EFFECTS OF UNILATERAL DESTRUCTION OF THE CERVICO–VAGINAL PLEXUS ON OVULATION IN THE RAT
Authors: DOMÍNGUEZ ROBERTO , ZIPITRÍA DOMINGO , AGUILAR LYLA , RIBONI LAURA
Published: December 2008

Hemidestruction of the cervico–vaginal plexus in 4- or 5-day cyclic rats was performed. After recovery, all animals had normal oestrous cycles. At oestrus itself, however, the number of ova released by lesioned animals was respectively 23% and 50% less than in the sham-operated and intact control rats. The possible participation of peripheral innervation in normal ovarian function is discussed.
EFFECT OF OESTROGEN ON GONADOTROPHIN RELEASE IN STUMPTAILED MONKEYS (MACACA ARCTOIDES) TREATED CHRONICALLY WITH AN AGONIST ANALOGUE OF LUTEINIZING HORMONE RELEASING HORMONE
Authors: FRASER H. M.
Published: December 2008

Nine adult female stumptailed monkeys (Macaca arctoides) treated chronically with daily s.c. injections of d-Ser(But)6des-Gly10,Proethylamide9, luteinizing hormone releasing hormone (LH-RH agonist) to inhibit ovulation, were tested for their ability to respond to an oestrogen provocation test (positive feedback). On two occasions during treatment with the LH-RH agonist (first test between 10 and 35 weeks after treatment had started; second test between 30 and 60 weeks after) the animals were given an i.m. injection of 50 μg oestradiol benzoate/kg in arachis oil. Controls were tested between days 1 and 5 of the normal cycle. In the control monkeys oestrogen induced a clear rise in LH and FSH concentrations in the blood, with highest values between 48 and 60 h after treatment. In marked contrast, none of the animals treated with LH-RH agonist showed this pattern of response. In the first test, five of the nine monkeys showed no rise in LH while in the remaining animals the response was diminished or delayed, and in the second test all nine failed to show a significant rise in LH. In all agonist-treated monkeys oestrogen failed to cause an FSH rise in either test.

Thus, chronic treatment with LH-RH agonist in the monkey either abolishes, diminishes or delays the oestrogen-induced LH surge. Since, in the primate, oestrogen appears to release LH by acting directly on the pituitary gland exposed to pulses of LH-RH from the hypothalamus it appears that the LH surge is inhibited primarily because the pituitary gland has been exposed to prolonged stimulation by the agonist.
RESPONSES OF RAT FETAL ADRENALS TO SYNTHETIC ADRENOCORTICOTROPHIC HORMONE AND α-MELANOCYTE-STIMULATING HORMONE: IN-VIVO AND IN-VITRO STUDIES
Authors: DUPOUY J. P.
Published: December 2008

The response of the adrenals from rat fetuses at 16,18 and 20 days of gestation to 1–24 ACTH and α-melanocyte-stimulating hormone (α-MSH) was studied in vitro. The response to 1–24 ACTH increased as gestation progressed. By the end of fetal life, corticosterone release induced by ACTH from whole adrenals was greater than that observed with adrenal tissue from non-pregnant adult female rats. High doses of α-MSH also stimulated adrenal activity but the response to ACTH was always higher than that to α-MSH.

The effect of 1–24 ACTH and α-MSH on fetal adrenal growth was also compared in vivo. The adrenal atrophy induced by fetal hypophysectomy on day 17 of gestation could be prevented by i.m. administration of 10 μg 1–24 ACTH or α-MSH. However, the adrenal growth was greater in ACTH-treated fetuses than in α-MSH-treated ones. Later in gestation, between days 19 and 20, 1–24 ACTH but not α-MSH was able to prevent atrophy induced by fetal hypophysectomy.

These findings are discussed in relation to the literature on levels of ACTH and α-MSH in the plasma and pituitary glands of the rat throughout the last third of gestation. High levels of ACTH in the fetal circulation contrast sharply with very weak or undetectable concentrations of α-MSH. Since the present data suggest that both trophic and steroidogenic activities of ACTH were greater than those of α-MSH, it may be concluded that ACTH but not α-MSH plays a major physiological role during gestation in the regulation of both fetal adrenal growth and function in the rat.
RETARDATION OF FIRST OVULATION IN PUBERTAL RATS AFTER TREATMENT WITH 5α-ANDROSTANE-3α,17β-DIOL OR ITS 3β-EPIMER
Authors: KRAMER P. , MEIJS-ROELOFS H. M. A.
Published: December 2008

The effect was studied of five daily injections of 50 μg of either 5α-androstane-3α,17β-diol (3α-androstanediol) or its 3β-epimer (3β-androstanediol), starting on day 22 of life, on sexual maturation in female rats. No difference was found in the age and body weight at first oestrus between oil-treated rats and rats treated with either 3α- or 3β-androstanediol. The only difference observed between these groups consisted of the occurrence of a 'pinhole' vaginal opening a few days before oestrus in 50% of the steroid-treated rats; in oil-treated rats immediate full vaginal opening and first oestrus coincided in ten out of 12 rats.

Different effects were obtained when the higher dose of 100 μg daily was used; effects were dissimilar in rats treated with 3α- and 3β-androstanediol. If administration of the higher dose of 3β-androstanediol was started on day 22 and continued until the day of full vaginal opening and first oestrus, a significant delay of this first oestrus, preceded by a few days of a 'pinhole' type of vaginal opening, was observed. After administration of the higher dose of 3α-androstanediol a 'pinhole' type of vaginal opening, accompanied by dioestrous-like vaginal smears, was also found, but oestrus did not occur during the period when injections were given. After the injections were stopped on day 45, first oestrus developed within 6 days in all rats.

The previous findings of others that administration of 3β-androstanediol to the immature female rat may induce precocious puberty (i.e. precocious vaginal opening and first ovulation) were not confirmed in the present study. Our results indicate that high doses of free 3α-androstanediol, and to a lesser degree 3β-androstanediol, may even delay first ovulation in the rat. A possible interference of 3α-androstanediol with the triggering of the first ovulatory gonadotrophin peaks is discussed.
POSSIBLE ROLE OF 5α-ANDROSTANE-3α,17β-DIOL IN THE CONTROL OF FOLLICLE-STIMULATING HORMONE SECRETION IN THE IMMATURE FEMALE RAT
Authors: MEIJS-ROELOFS H. M. A. , KRAMER P. , GRIBLING-HEGGE L.
Published: December 2008

A possible role of 5α-androstane-3α,17β-diol (3α-androstanediol) in the control of FSH secretion was studied at various ages in ovariectomized rats. In the rat strain used, vaginal opening, coincident with first ovulation, generally occurs between 37 and 42 days of age. If 3α-androstanediol alone was given as an ovarian substitute, an inhibitory effect on FSH release was evident with all three doses tested (50, 100, 300 μg/100 g body wt) between 13 and 30 days of age; at 33–35 days of age only the 300 μg dose caused some inhibition of FSH release. Results were more complex if 3α-androstanediol was given in combined treatment with oestradiol and progesterone. Given with progesterone, 3α-androstanediol showed a synergistic inhibitory action on FSH release between 20 and 30 days of age. However, when 3α-androstanediol was combined with oestradiol a clear decrease in effect, as compared to the effect of oestradiol alone, was found between 20 and 30 days of age. Also the effect of combined oestradiol and progesterone treatment was greater than the effect of combined treatment with oestradiol, progesterone and 3α-androstanediol. At all ages after day 20 none of the steroid combinations tested was capable of maintaining FSH levels in ovariectomized rats similar to those in intact rats.

It is concluded that 3α-androstanediol might play a role in the control of FSH secretion in the immature rat, but after day 20 the potentially inhibitory action of 3α-androstanediol on FSH secretion is limited in the presence of oestradiol.
DRUG-INDUCED HYPERPROLACTINAEMIA AND DISCHARGES OF LUTEINIZING HORMONE EVOKED BY OESTROGEN IN OVARIECTOMIZED RHESUS MONKEYS
Authors: MARTENSZ N. D. , HERBERT J.
Published: December 2008

Ovulatory failure associated with hyperprolactinaemia has been attributed to the inability of oestrogen to evoke a preovulatory discharge of gonadotrophins. This hypothesis was tested in ovariectomized rhesus monkeys rendered hyperprolactinaemic by treatment with two dopamine antagonists, domperidone, a compound reported not to cross the blood–brain barrier in rats, and sulpiride, a drug with known actions on both pituitary and central dopaminergic receptors. An artificial surge of oestrogen similar to that observed at mid-cycle in intact monkeys was obtained with subcutaneous capsules filled with oestradiol-17β. Treatment with either drug increased prolactin concentrations to 1·0 i.u./l or more compared with control values of 0·1–0·3 i.u./l. In the presence of these greatly increased prolactin levels, a normal discharge of LH, indistinguishable from that observed in control animals, was provoked by oestrogens in all but one drug-treated monkey. Furthermore, neither the basal (pre-oestrogen) level of LH nor the negative feedback action of oestrogen was consistently altered in hyperprolactinaemic monkeys. Administration of progesterone or 17α-hydroxyprogesterone to simulate more closely the conditions observed in intact animals during the periovulatory period did not alter the LH discharge induced by oestrogen in animals treated with domperidone.

The present results suggest that the high levels of prolactin brought about by dopaminergic blockade do not affect the positive feedback action of oestrogen. Furthermore, low levels of progestins do not sensitize the hypothalamic-pituitary axis towards an inhibitory action of prolactin on oestrogen-induced LH release. The rhesus monkey thus differs from other species, including man, in which artificially induced hyperprolactinaemia may impair or abolish the positive feedback action of oestrogen.
EFFECT OF CORTISOL OR ADRENOCORTICOTROPHIN ON RELEASE OF LUTEINIZING HORMONE INDUCED BY LUTEINIZING HORMONE RELEASING HORMONE IN THE DAIRY HEIFER
Authors: MATTERI R. L. , MOBERG G. P.
Published: December 2008

During treatment with cortisol or ACTH, dairy heifers were given two doses of LH releasing hormone (LH-RH) spaced 1·5 h apart. Serum concentrations of cortisol and LH were monitored during each treatment. Treatment with both ACTH and cortisol raised plasma cortisol levels above the respective saline controls (P<0·001). Neither treatment affected basal LH concentrations. A slight depression in LH response was seen in the cortisol-treated animals after the first LH-RH injection, as shown by a statistically significant depression at three of the sample times. There was no significant difference between treated and control LH values after the second LH-RH administration. Treatment with ACTH resulted in significantly reduced LH values at all sample times after both injections of LH-RH.
BIOLOGICAL AND IMMUNOLOGICAL PROPERTIES OF DIFFERENT MOLECULAR SPECIES OF HUMAN FOLLICLE-STIMULATING HORMONE: ELECTROFOCUSING PROFILES OF EIGHT HIGHLY PURIFIED PREPARATIONS
Authors: ZAIDI A. A. , FRÖYSA B. , DICZFALUSY E.
Published: December 2008

Eight highly purified human pituitary FSH preparations and purified preparations of the α-and β-subunits of FSH were fractionated by an electrofocusing technique in the pH range of 2·5–10·0 on a sucrose density gradient. The human (h) FSH activity in each of the eluted fractions was monitored by an in-vitro bioassay and a radioimmunoassay procedure.

After electrofocusing, the overall recovery of the biological activity of the eight preparations was between 80 and 94% (mean 88%). On the other hand, the recovery of immunoreactivity ranged between 30 and 84% (mean 71%). A loss of over 85% of hFSH immunoreactivity was observed when the α- and β-subunits of hFSH were fractionated by the same procedure.

The specific loss of varying amounts of immunoreactivity in all preparations during electrofocusing was also reflected by a proportional increase in the ratios of biological activity (B) to immunoreactivity (I); preparation A, which exhibited a loss of 70% of the immunoreactivity, had a threefold increase in its B/I ratio after electrofocusing.

Significant differences were observed in the electrofocusing profiles of the eight preparations both in terms of their pI values and of their spread.

The disparity in the relative distribution of hFSH activities in different pH regions suggested major differences in the carbohydrate moieties (sialic acid content) of the preparations studied, probably as a result of the chemical manipulations involved in the purification of the hormone. It is suggested that a combination of several (but certainly not all) of the preparations might serve as a provisional International Reference Preparation for hFSH radioimmunoassays.
EFFECTS OF HYDROXYSTEROID DEHYDROGENASE INHIBITORS ON IN-VITRO AND IN-VIVO STEROIDOGENESIS IN THE OVINE ADRENAL GLAND
Authors: SINGH-ASA P. , JENKIN G. , THORBURN G. D.
Published: December 2008

The effectiveness of trilostane and azastene as inhibitors of adrenal steroidogenesis was compared by in-vitro and in-vivo methods. A radioimmunoassay was developed for the measurement of cortisol in ovine plasma, incubation medium and tissue extract using a specific antiserum raised against cortisol 21-acetate,3-carboxymethyloxime : bovine serum albu

Trilostane (20 μmol/l) decreased cortisol synthesis and release both in unstimulated and in ACTH-stimulated adrenal tissues in vitro. The same concentration of azastene had a lesser effect on unstimulated adrenals and was completely ineffective in blocking the stimulatory action of ACTH. In vivo, trilostane suppressed adrenal steroidogenesis in pregnant and cyclic ewes but the suppression in pregnant ewes was over a longer period, and after lower doses.

It is concluded that trilostane had an inhibitory effect on ovine adrenal steroidogenesis both in vitro and in vivo.
LACK OF EFFECT OF TREATMENT WITH OESTROGEN IN ADVANCING PUBERTY IN THE GUINEA-PIG
Authors: CALIGARIS L. , DONOVAN B. T.
Published: December 2008

Guinea-pigs were injected with 500 ng oestradiol benzoate or 0·1 ml arachis oil at 0, 5, 10, 20 or 25 days of age, or 2 μg oestradiol benzoate/100 g body wt at 25 days, in order to determine whether puberty would be advanced, as in the rat. It was not. Repeated injections of 100 ng oestradiol benzoate or 0·1 ml arachis oil for 5 days beginning at 0, 10, 20 or 25 days of age, or 2 μg oestradiol benzoate/100 g body wt beginning at 25 days, were similarly ineffective.
EFFECTS OF GLUCOCORTICOIDS AND DISODIUM CROMOGLYCATE ON AVIDIN PRODUCTION IN CHICK TISSUES
Authors: NORDBACK ISTO , JOENSUU TIMO , TUOHIMAA PENTTI
Published: December 2008

The effects of anti-inflammatory glucocorticoids and a membrane stabilizer (disodium cromoglycate) on avidin induction were studied. Chicks were primed for 0, 3 or 7 days with diethylstilboestrol (DES; 0·5 mg/day per animal, s.c.). Actinomycin D (0·2 mg/kg, i.p.) stimulated avidin production in the oviduct, intestine, lung and wing muscle of both DES-primed and unprimed chicks. Prednisolone (5 mg/animal, i.m.) given 1 h before actinomycin D reduced the avidin amounts to control levels in the unprimed oviducts and in non-oviductal tissues. The signs of inflammation (ascites, oedema) in chicks receiving actinomycin D also disappeared with prednisolone premedication. Cortisol (50 mg/animal, i.m. or 1, 5 or 50 μg/ml medium), prednisolone (5 mg/animal, i.m. or 0·5, 5, 10 or 50 μg/ml medium) and dexamethasone (1 mg/animal, i.m. or 0·05 or 0·5 μg/ml medium) stimulated avidin production in DES-primed oviducts in vivo and in vitro. Culture in vitro induced avidin production in lung and oviduct but not in wing muscle. This avidin production in culture was not inhibited by cortisol, prednisolone or disodium cromoglycate. It is concluded that actinomycin D induces avidin production through its inflammatory effect and that the induction can be prevented by anti-inflammatory glucocorticoids. It is proposed that the 'spontaneous' avidin production in culture is not the effect of trauma during tissue preparation but rather a new form of avidin induction.