bluuebunny/crossref_metadata_2025_split huggingface dataset:
SERUM PROLACTIN LEVELS IN CASTRATED RAMS AT VARIOUS TIMES OF THE YEAR AND DURING TREATMENT WITH ANDROGENS OR OESTROGEN
Authors: PARROTT R. F. , HILLS F. 
Published: December 2008

SUMMARY
Prolactin concentrations were measured in serum from wethers at various times of the year before and during treatment with testosterone propionate, dihydrotestosterone propionate, 19-hydroxytestosterone dipropionate and oestradiol dipropionate. Levels of prolactin in serum were lower in untreated wethers during short (October) than during long (April–August) days. Seasonal differences persisted throughout the experiment but became less obvious during treatment with oestradiol dipropionate and 19-hydroxytestosterone dipropionate, both of which raised prolactin concentrations. Neither testosterone propionate nor dihydrotestosterone propionate altered the levels of prolactin.
CONCENTRATION OF 5-METHOXYTRYPTOPHOL IN PINEAL GLAND AND PLASMA OF THE RAT
Authors: CARTER S. J. , LAUD C. A. , SMITH I. , LEONE R. M. , HOOPER R. J. L. , SILMAN R. E. , FINNIE M. D. A. , MULLEN P. E. , LARSON-CARTER D. L. 
Published: December 2008

SUMMARY
5-Methoxytryptophol, a serotonin metabolite, was measured by gas chromatography–mass spectrometry in pineal glands, plasma and control tissues (cerebral cortex and salivary glands) from male rats kept in a controlled lighting environment. In the pineal gland the level of 5-methoxytryptophol was significantly higher during the dark period than during the light, the absolute levels being an order of magnitude less than those of melatonin. In the plasma, the levels showed a reverse situation with respect to lighting conditions. No correlation was found between the 5-methoxytryptophol levels in plasma and the pineal gland in individual animals. These results suggest that there is no obvious correlation between pineal content and pineal activity. This may be due to a combination of rapid turnover, secretion and/or peripheral conversion of another 5-methoxyindole to 5-methoxytryptophol.
PROGESTERONE RECEPTORS AND RNA POLYMERASE ACTIVITY IN THE RAT UTERUS DURING THE OESTROUS CYCLE
Authors: KURL R. N. , BORTHWICK N. M. 
Published: December 2008

SUMMARY
The concentrations of progesterone receptors in uterine cytoplasm and nuclei were measured during the oestrous cycle of the rat. The concentration of cytoplasmic progesterone receptors was highest at pro-oestrus and declined at oestrus to reach lowest levels at metoestrus before rising at dioestrus. Similar changes were observed in the concentration of nuclear progesterone receptors, the highest levels being present at pro-oestrus and dioestrus. In addition, both activities A and B of RNA polymerase mirrored these alterations in nuclear receptor levels.
HORMONE REPLACEMENT THERAPY IN THE MENOPAUSE: A SUITABLE ANIMAL MODEL
Authors: PAPADAKI LUCIENNE , BEILBY J. O. W. , CHOWANIEC JANINA , COULSON W. F. , DARBY A. J. , NEWMAN J. , O'SHEA A. , WYKES J. R. 
Published: December 2008

SUMMARY
Female CBA mice, aged 11 months, were treated cyclically with oral ethynyl oestradiol or oestrone sulphate for 3 months. The ovaries of all animals appeared to be atrophied. Target tissues throughout the genital tract showed a response to both oestrogens. Electron microscopy of both the endometrium and the urothelium demonstrated morphological changes characteristic of increased cellular metabolic activity in the treated mice. Endometrial hyperplasia developed in both treatment groups but more pronounced epithelial changes occurred with oestrone sulphate. This hyperplasia was accompanied by a doubling in the number of uterine cytoplasmic oestrogen receptors. A 50% fall in serum levels of luteinizing hormone in the treated mice revealed that the hypothalamic-pituitary system was still intact. Both oestrogens improved skeletal balance by changes in cortical-endosteal bone remodelling. The results suggest that the CBA strain of mouse is a suitable model for the study of the human climacteric and its response to hormone replacement therapy.
INTERACTION BETWEEN THEOPHYLLINE AND OESTROGEN IN THE RAT UTERUS
Authors: STEINSAPIR J. , ROJAS A. M. , FERNÁNDEZ A. , ALBURQUERQUE M. , LEÓN S. , BUSTÓN P. , PACHECO R. , MUNIZAGA A. , HABASH L. , OJEDA J. M. , TCHERNITCHIN A. 
Published: December 2008

Theophylline alone or in the presence of 0·001, 0·01, 0·1 or 1 μg oestradiol-17β/100 g body wt increased uterine RNA and protein content 6 h after administration. Uterine oedema induced by physiological doses of oestradiol-17β was increased further in the presence of theophylline.
Theophylline decreased the number of eosinophils in the blood and concurrently decreased oestrogen-induced uterine eosinophilia at doses of 0·01,0·1, 1,10 or 30 μg oestradiol-17β/100 g body wt. Oestrogen binding by uterine eosinophils in vitro increased in the presence of theophylline. This effect of theophylline could explain the increase of oestrogen-induced uterine oedema in vivo.
NON-PROTEIN-BOUND OESTROGENS IN PLASMA AND URINARY EXCRETION OF UNCONJUGATED OESTROGENS IN NON-PREGNANT WOMEN
Authors: SPEIGHT ALISON C. , HANCOCK K. W. , OAKEY R. E. 
Published: December 2008

The concentrations of oestrone and oestradiol-17β in peripheral plasma and the urinary excretion of unconjugated oestrone and unconjugated oestradiol-17β were measured by radioimmunoassay in 31 matched samples from seven young women. The concentrations of oestrone and oestradiol-17β not bound to protein in the plasma samples were measured following equilibrium dialysis.
The urinary excretion of unconjugated oestrone (0·70 ± 0·34 nmol/24 h, mean ±s.d., n = 28) was found to be significantly, but poorly, correlated with the concentration of non-protein-bound oestrone in plasma (10·2 ± 3·8 pmol/l) (r = 0·44, P < 0·05). Similarly, the urinary excretion of unconjugated oestradiol-17β (0·29 ± 0·16 nmol/24 h, n = 30) was found to be significantly, but still rather poorly correlated with the concentration of non-protein-bound oestradiol-17β in plasma (7·4 ± 5·3 pmol/l) (r = 0·58, P< 0·001). Since the calculated proportions of oestrone and oestradiol-17β in plasma not bound to protein (3·4 ± 0·3% and 1·7 ± 0·2% respectively) remained fairly constant (coefficient of variation 9 and 10% respectively), measurement of oestrone or oestradiol-17β in plasma provided a better guide to the biologically available (non-protein-bound) hormone than did measurement of urinary unconjugated oestrogen.
The mean renal clearance of both non-protein-bound oestrone and non-protein-bound oestradiol-17β (50 ± 21 and 36 ± 23 ml/min) was less than that of creatinine (114 ± 31 ml/min) indicating absorption and/or metabolism of each hormone by the kidney tubule.
PROPERTIES OF RAT ADRENAL ZONA RETICULARIS CELLS: PRODUCTION AND STIMULATION OF CERTAIN STEROIDS
Authors: BELL J. B. G. , GOULD R. P. , HYATT P. J. , TAIT J. F. , TAIT S. A. S. 
Published: December 2008

The outputs of corticosterone, deoxycorticosterone and androstenedione from dispersed, purified rat adrenal zona reticularis and zona fasciculata cells have been measured by radioimmunoassay.
Preferential production of deoxycorticosterone by zona reticularis cells was demonstrated by their higher basal deoxycorticosterone: corticosterone ratio when compared with zona fasciculata cells.
Adrenocorticotrophin (ACTH) stimulated corticosterone output by all cell pools prepared by unit gravity (1 g) sedimentation, zona fasciculata cells being stimulated 130-fold compared with 20-fold for the zona reticularis cells in relation to their basal corticosterone output.
In every cell pool, ACTH stimulated the output of corticosterone more than it stimulated the output of deoxycorticosterone. In parallel cell preparations, it was shown that ACTH increased the conversion of tracer amounts of radioactive deoxycorticosterone to corticosterone and decreased the conversion of radioactive corticosterone to 11-dehydrocorticosterone. Adrenocorticotrophin did not increase the conversion of radioactive deoxycorticosterone to total 11-oxygenated steroids (corticosterone+ 11-dehydrocorticosterone). It is unlikely therefore that ACTH stimulates 11 β-hydroxylation.
Data indicate that the ratio of deoxycorticosterone to total 11-oxygenated steroids (corticosterone +11-dehydrocorticosterone) is characteristic for each cell type, and that this ratio will be relatively independent of ACTH stimulation or the amount of pregnenolone substrate available.
Basal androstenedione outputs were similar for both types of cell, and ACTH stimulation was very small, being slightly greater for zona fasciculata than for zona reticularis cells.
The contribution of the zona reticularis cells to the basal output of any steroid by the cells of the inner two zones of the adrenal cortex of the rat was relatively small (20% for deoxycorticosterone and 10% for corticosterone) and was even less after stimulation by ACTH. Unless a specific stimulus can be found, therefore, a significant role for the zona reticularis cannot yet be established.
PERIPHERAL CONCENTRATIONS OF PROGESTERONE, CORTISOL, ALDOSTERONE, SODIUM AND POTASSIUM IN THE PLASMA OF THE TADMIT EWE DURING PREGNANCY AND PARTURITION
Authors: BOULFEKHAR LOUISA , BRUDIEUX ROGER 
Published: December 2008

The peripheral blood concentrations of progesterone, cortisol, aldosterone and electrolytes were measured simultaneously in 16 multiparous ewes of the Tadmit Algerian breed during pregnancy and parturition.
Plasma progesterone concentrations were similar to those of the luteal phase of the oestrous cycle during the first third of gestation. Between 60 and 135 days after mating, the levels of plasma progesterone increased steadily to values eight times those found in early pregnancy. However, no change was observed from days 43 to 28 before parturition. Mean progesterone concentrations declined during the 17 days preceding lambing, decreasing more quickly during the last 3 days.
Pregnancy did not increase the levels of plasma cortisol and the mean values during pregnancy did not exceed 0·5 μg/100 ml until 90 days after mating. It then tended to decrease between days 57 and 17 before parturition, before rising slightly on both day 7 and on the day of lambing.
Concentrations of plasma aldosterone were low during early pregnancy (about 2 ng/100 ml). Thereafter, as with progesterone, they rose from days 58 to 43, did not change from days 43 to 28 and increased again until maximum levels were reached 17 days prepartum and then levels decreased sharply until 7 days before lambing. At this stage, progesterone levels continued to decrease during the last 7 days while aldosterone concentrations once more increased.
Sodium and potassium concentrations changed little during pregnancy, although the sodium: potassium ratio tended to increase during the last 17 days of pregnancy. It is suggested that changes in the levels of plasma aldosterone during gestation in the ewe are the result of the competitive inhibition of aldosterone by progesterone at a renal level and that the rise of aldosterone during the last few days of pregnancy is largely due to the stimulation of renin substrate production by oestrogens whose values are high at this period.
DIURNAL VARIATIONS OF PLASMA PROLACTIN IN GROWING SHEEP UNDER TWO LIGHTING RÉGIMES AND THE EFFECT OF PINEALECTOMY
Authors: BROWN WENDY B. , FORBES J. M. 
Published: December 2008

The role of the pineal gland in mediating the stimulatory effect of long daylength on blood levels of prolactin was investigated in 24 growing castrated sheep. Eight were pinealectomized, eight were sham-pinealectomized and eight remained as unoperated control animals. After a preliminary period with 12 h light:12 h darkness (12L: 12D) pairs of similar sheep were allocated to photoperiods of 16L: 8D or 8L: 16D for 15 weeks. Each animal was individually fed at the same level as its partner exposed to the other daylength. Blood samples were taken weekly by jugular venepuncture. On two occasions, once in the preliminary period (12L: 12D) and again 41 days after the start of the subsequent photoperiods, samples were taken through indwelling jugular catheters at frequent intervals for 24 h. The plasma samples were assayed for prolactin by radioimmunoassay and concentrations were higher in samples taken by jugular puncture.
There was a consistent positive effect of daylength on plasma prolactin in sheep with pineal glands that did not occur in pinealectomized sheep. In contrast, pinealectomy did not block the marked rise in prolactin that occurred at dusk. It appears that the effect of the photoperiod on levels of plasma prolactin throughout the day and night is not mediated by the same mechanism as that which controls the surge of prolactin at dusk in the sheep.
INTERACTION OF SPIRONOLACTONE WITH OESTRADIOL RECEPTORS IN CYTOSOL
Authors: LEVY J. , BURSHELL A. , MARBACH M. , AFLLALO L. , GLICK S. M. 
Published: December 2008

The role of spironolactone in the aetiology of gynaecomastia was examined in terms of its ability to bind to the oestrogen receptor in cytosol, to cause specific oestrogenic effects in the absence of endogenous oestrogen and to be antioestrogenic in the presence of oestradiol. Tamoxifen, a non-steroidal antioestrogen, was chosen as an internal standard for comparison.
Spironolactone and tamoxifen competitively inhibited the binding of oestradiol-17β to its receptor in uterine and mammary cytosol, with inhibition constants of 2 × 10−5 and 1 × 10−7 respectively.
To measure oestrogenic or antioestrogenic effects of the drugs five indices believed to be specific markers for oestrogen action were studied: uterine to body weight ratio, uterine protein content, oestradiol receptor in cytosol, progesterone receptor in cytosol and uterine peroxidase activity.
Spironolactone, when administered for 3 successive days (40 μg/day) to immature female rats, increased all of the five indices of oestrogen agonistic activity. The oestrogenantagonistic properties of the drug were evaluated by comparing the oestradiol-injected group (5 μg) to the oestradiol + spironolactone-injected group. A decrease was noted in all indices measured except for progesterone receptors in cytosol. Spironolactone appeared to be very similar to tamoxifen in its action both as an oestrogen and as an antioestrogen.
The antioestrogenic effect of spironolactone cannot be explained by previously proposed mechanisms of action for the drug such as decreased synthesis of testosterone or inhibition of dihydrotestosterone binding to its receptor. These results suggest that spironolactone-induced gynaecomastia may be modulated by its action at both the oestrogen and dihydrotestosterone receptor in cytosol.
DIFFERENTIAL SENSITIVITY OF PROLACTIN RELEASE TO DOPAMINE AND THYROTROPHIN-RELEASING HORMONE IN INTACT AND PITUITARY STALK-SECTIONED RHESUS MONKEYS
Authors: NORMAN R. L. , QUADRI S. K. , SPIES H. G. 
Published: December 2008

The effects of dopamine and thyrotrophin-releasing hormone (TRH) on prolactin release was studied in 14 intact and six pituitary stalk-sectioned (SS) female rhesus monkeys (Macaca mulatta). Baseline prolactin values were ninefold higher in SS animals (149 ± 16 ng/ml) than in intact animals (16 ± 1 ng/ml).
Prolactin release after intravenous administration of TRH in doses of 0,125,250, 500 and 1000 ng revealed that SS monkeys were more sensitive to the prolactin-releasing activity of this tripeptide than were intact animals. A significant (P < 0·05) increment in serum prolactin was observed in SS animals after injection of 125 ng TRH whereas 250 ng was required to raise prolactin levels in the circulation of intact animals significantly (P <0·05). Furthermore, at each comparable dose level of TRH, the increment in serum prolactin was distinctly greater in SS animals than in intact monkeys.
Infusion of dopamine at the rate of 10 μg/kg body weight per min significantly (P <0·05) lowered prolactin levels within 60 min in intact animals and no further decline was observed with 20 or 40 μg dopamine. Serum prolactin concentrations were not affected by saline infusion or by 5 μg dopamine. Infusion of dopamine at the rate of 10 μg/kg body wt per min also resulted in significant (P <0·01) suppression of serum prolactin in SS animals. This prolactin decrease was apparent within 40 min. Prolactin release after 500 ng TRH was less in these dopamine-treated SS monkeys than after an infusion of saline. Higher doses of dopamine (20 and 40 μg) did not cause a further decrease in basal serum prolactin concentrations, but these two dopamine treatments blocked the increase in prolactin elicited by 500 ng TRH.
The results suggest that the removal of hypothalamic influence, possibly related to the effects of dopamine, renders the pituitary gland more sensitive to the prolactin-releasing action of TRH.
REGULATION BY THE PITUITARY GLAND OF CIRCADIAN RHYTHMS IN THE HAMSTER
Authors: ZUCKER IRVING , CRAMER CATHERINE P. , BITTMAN E. L. 
Published: December 2008

SUMMARY
Locomotor activity of male hamsters was recorded during long-term exposure to constant light (LL), constant darkness (DD) and during entrainment (modification of a circadian rhythm) to a 14 h light: 10 h darkness photoperiod (14L: 10D). In LL the period of the activity cycle was substantially longer in hypophysectomized than in control animals. This difference persisted during tests in DD. Although hypophysectomy reduced the duration of the active phase in some hamsters, overall the difference between the groups was not significant. The phase angle of onset of activity in 14L: 10D was not affected by hypophysectomy. Hypophysectomized female hamsters tested in DD had activity rhythms whose periods were longer than those of control animals; they were also significantly less active than corresponding controls during the first 4 h of the subjective night but the duration of the active phase did not differ significantly between the groups. These results suggest that hormones of the pituitary-gonadal axis modulate the period of circadian oscillation.
EFFECT OF ADRENALECTOMY OR CASTRATION ON THE INHIBITION OF GONADOTROPHIN SECRETION INDUCED BY HYPERPROLACTINAEMIA IN THE ADULT MALE RAT
Authors: McNEILLY A. S. , SHARPE R. M. , FRASER H. M. 
Published: December 2008

SUMMARY
To investigate the role of adrenal and gonadal steroids in the long-term suppression of gonadotrophin secretion induced by prolactin the effects of adrenalectomy or castration on the serum and pituitary levels of LH, FSH and prolactin and the hypothalamic content of LH releasing hormone (LH-RH) have been studied in adult male rats with hyper prolactinaemia produced by the transplantation of pituitary glands under the kidney capsule.
Levels of LH and FSH in serum were significantly suppressed in all intact pituitary-grafted rats. Adrenalectomy on the day of pituitary implantation or 20 days later did not affect this suppression. However, castration on days 0,28 or 49 after pituitary grafting resulted in a rise in levels of FSH in serum indistinguishable from that in control rats. While the rise in levels of LH after castration on day 0 was the same as the controls, this increase was significantly reduced 2 days after castration on days 28 and 49 after pituitary grafting.
Castration resulted in an increase in the pituitary content of LH and a reduction in the hypothalamic content of LH-RH but no change in the pituitary content of FSH. Hyperprolactinaemia did not appear to affect these responses.
The present results showed clearly that the gonad but not the adrenal must be present for prolactin to exert an inhibitory effect on gonadotrophin secretion.
DIURNAL VARIATION IN THE INDUCIBILITY OF LUTEAL 20α-HYDROXYSTEROID DEHYDROGENASE IN PREGNANT RATS
Authors: HICKMAN-SMITH DAVID , KUHN N. J. 
Published: December 2008

SUMMARY
Luteolysis was induced in rats during late pregnancy by fetoplacental removal, and was monitored by the increased activity of luteal 20α-hydroxysteroid dehydrogenase (20α-OHSDH). The extent of enzyme induction over a given length of time varied according to the time of day at which the fetuses and placentae were removed, 11.00 and 21.00 h appearing to give optimal and minimal enzyme activities respectively. The 20α-OHSDH was more readily induced on day 19 than on day 18.
PARTIAL PURIFICATION OF LOW MOLECULAR WEIGHT NON-SUPPRESSIBLE INSULIN-LIKE ACTIVITY FROM HUMAN PLASMA: DEMONSTRATION OF THE PRESENCE OF MULTIPLE FORMS
Authors: COCKERILL P. N. , CORNELL H. J. , HERINGTON A. C. 
Published: December 2008

An alternative procedure for the separation of insulin-like growth factors from plasma, avoiding the harsh conditions of acid–ethanol extraction, suggested that several factors which have activity in the isolated rat adipocyte assay may be present.
The initial step consisted of ion-exchange chromatography of an enriched Cohn fraction (IV-1) on SP-Sephadex using ammonium acetate buffers. The major activity appeared in a fraction eluted at pH 7·1–9·4. When this fraction was subjected to gel filtration on Sephadex G-75 in 1% formic acid, most of the activity was recovered in a fraction of molecular weight of 5000–8000, but up to 25% of the activity applied remained in a much higher molecular weight form. The active material of low molecular weight was recovered at a considerably greater yield compared with that obtained by the more conventional acid–ethanol extraction followed by gel filtration on Sephadex G-75. The fraction was further purified by DEAE–Sephadex chromatography and isoelectric focussing. Non-suppressible insulin-like activity (NSILA) of pI 4·8 and 6·0 were the major species detected. The results were in contrast with those obtained using acid–ethanol extraction of the Cohn fraction, where the major species were of pI 6·0 and 8·0. The presence of multiple forms of NSILA would thus appear to justify the use of alternative methods of purification.
RELATIONSHIP BETWEEN THE DECIDUAL RESPONSE AND OVARIAN STEROIDOGENESIS IN THE UNILATERALLY OVARIECTOMIZED PSEUDOPREGNANT RAT
Authors: TERRANOVA P. F. 
Published: December 2008

The influence of the decidual cell reaction (DCR) on luteal and non-luteal ovarian steroidogenesis was ascertained on day 8 of pseudopregnancy in unilaterally ovariectomized rats. Whether a 'local' interaction existed between the DCR and ovarian steroidogenesis was of particular interest. Holtzman rats were subjected to unilateral ovariectomy and after exhibiting two successive oestrous cycles, they were rendered pseudopregnant by cervical stimulation at oestrus (day 1). On day 5 of pseudopregnancy, rats were subjected to a unilateral stimulus to induce a decidual cell reaction (ipsilateral or contralateral to the remaining ovary) or to sham-operation. On day 8 of pseudopregnancy, they were killed by decapitation and serum was stored for radioimmunoassay of progesterone, androgen, oestradiol, prolactin, FSH and LH. Also the corpora lutea and non-luteal portion of the ovary (NLO) were incubated for 2 h in Krebs–Ringer bicarbonate buffer. Steroid concentrations were determined in the corpora lutea and NLO before and after incubation and in the incubation media.
No differences were observed between groups (no DCR, ipsilateral DCR, contralateral DCR) in the serum concentrations of progesterone, androgen, FSH, LH or prolactin. However, serum levels of oestradiol were significantly lower than those levels in rats lacking DCR. No 'local' steroidogenic effect of the DCR was observed in the corpora lutea or NLO; although it appeared that the DCR could stimulate luteal progesterone production since corpora lutea from rats with ipsilateral DCR produced more progesterone in vitro than rats lacking DCR (but not than rats with contralateral DCR). The presence of a DCR was associated with lower levels of oestradiol in serum, corpora lutea and NLO and also with lower in-vitro production of oestradiol by NLO and corpora lutea than unilaterally ovariectomized rats lacking DCR. Since androgen levels in serum, corpora lutea and NLO were not altered by the presence of a DCR, it seems plausible that the DCR may alter oestrogen synthesis (aromatase) in the ovary.