bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTERACTION BETWEEN PROLACTIN AND ANDROGENS IN THE ACCESSORY SEX ORGANS OF MALE MICE
Authors: KEENAN E. J. , KLASE P. A. , THOMAS J. A. 
Published: December 2008

Treatment of adult male mice with varying doses of prolactin increased the weights of the seminal vesicles and the anterior prostate gland. Only in the seminal vesicles were these increases in organ weights associated with increased levels of DNA. In castrated mice, prolactin alone failed to alter the weights of the accessory sex organs or DNA content. However, the simultaneous administration of prolactin and testosterone resulted in enhanced androgenic stimulation of seminal vesicle weights and their DNA content. Prostatic weights, but not DNA content, were augmented by treatment with prolactin and testosterone. Although the kidneys exhibited androgen sensitivity, prolactin failed to enhance the effect of testosterone upon the kidney. Augmentation of androgen action in the accessory sex organs was observed only after treatment with prolactin or growth hormone. Prolactin also enhanced the effects of dihydrotestosterone and 5α-androstane-3α, 17β-diol, but not of 5α-androstane-3β,17β-diol.
These studies revealed that prolactin enhances the proliferative actions of androgens in mouse seminal vesicles, but not in the anterior prostate glands or the kidneys.
PATTERNS OF PLASMA PROLACTIN IN POST-PARTUM SUCKLED COWS
Authors: WEBB R. , LAMMING G. E. 
Published: December 2008

Blood samples taken on alternate days through indwelling jugular venous catheters from 12 suckled cows between days 14 and 48 post partum contained significantly less prolactin than samples collected on intermediate days by jugular venepuncture. Samples taken through the catheter every 2 h for 72 h periods revealed a repetitive daily biphasic pattern of prolactin secretion with low concentrations at 09.00 and 19.00 h and high concentrations at 13.00 and 23.00 h.
In two groups of cows, one group calving at the beginning of March (increasing photoperiod) and the other calving during June (decreasing photoperiod), there was a significant negative correlation between stage of lactation and plasma prolactin concentrations in samples taken by venepuncture.
STIMULATION OF RELEASE OF LUTEINIZING HORMONE FROM CULTURED PITUITARY CELLS BY 2- AND 4-HYDROXYLATED OESTROGENS
Authors: FRANKS S. , MERRIAM G. R. , GOODYER CYNTHIA G. , NAFTOLIN F. 
Published: December 2008

We have examined the effects of the catechol oestrogens 2-hydroxyoestradiol (2-OHE2), 4-hydroxyoestradiol (4-OHE2) and 2-hydroxyoestrone (2-OHE1) and their corresponding primary oestrogens on secretion of LH and FSH by enzymatically dispersed rat anterior pituitary cells in monolayer culture.
Basal LH levels in the medium were significantly higher than in control wells when cells were exposed to 10−8m-oestradiol-17β for 40 h: oestrone and all three catechol oestrogens (in the same doses) also stimulated basal LH concentrations to levels quantitatively similar to those seen after oestradiol treatment. The same effects were observed when steroids were given at 10−9 mol/l. Oestradiol, 2-OHE2, and 4-OHE2 but not 2-OHE1 increased pituitary responsiveness to LH releasing hormone (LH-RH) (given in a range of doses from 10−11 to 10−6 mol/l). The responses of cells treated with 2-OHE2 and 4-OHE2 were similar, though less than the response seen after treatment with oestradiol. This contrasts with the very different oestrogenic effects of 2- and 4-OHE2 previously observed in vivo. Neither oestradiol nor the catechol oestrogens had any effect on basal or LH-RH-stimulated FSH release.
THE POSSIBLE ROLE OF PROLACTIN IN THE REGULATION OF NESTING BEHAVIOUR AND THE SECRETION OF LUTEINIZING HORMONE IN BROODY BANTAMS
Authors: LEA R. W. , DODS A. S. M. , SHARP P. J. , CHADWICK A. 
Published: December 2008

The time spent each day on the nest and the rate of formation of the brood patch before the onset of incubation were measured in bantams (Gallus domesticus) and related to changes in the concentrations of plasma LH and prolactin. The hens spent progressively more time on the nest in the 5 days before the onset of incubation so that by the first day of incubation they were spending more than 90% of their time in this way. The concentration of plasma prolactin increased while that of LH fell on successive days before the onset of incubation: the increase in plasma prolactin preceded the fall in plasma LH by 2 days. The formation of the brood patch closely followed the increase in the concentration of plasma prolactin. In four out of five bantams the increase in nesting behaviour was preceded by an increase in the secretion of prolactin. An injection of chicken prolactin antiserum into bantams incubating eggs resulted in a significant (P<0·05) increase in the plasma concentration of LH.
These observations suggest that, in the bantam, the onset of incubation is initiated by an increase in the secretion of prolactin which also suppresses the secretion of LH.
ACCUMULATION OF LUTEINIZING HORMONE, OESTRADIOL AND ANDROSTENEDIONE BY SHEEP OVARIAN FOLLICLES IN VIVO
Authors: McNATTY K. P. , DOBSON CAROLYN , GIBB MARION , KIEBOOM LINDA , THURLEY D. C. 
Published: December 2008

The temporal relationships between the levels of LH in peripheral plasma and in follicular fluid of ovarian follicles in anaesthetized sheep were investigated for a 10-h period after a single i.m. injection of LH releasing hormone (LH-RH; 100 μg). The ovarian secretion rates of oestradiol and androstenedione and the levels of these steroids accumulating in different sized follicles at varying time-intervals after the LH-RH injection were also compared.
The data show that the rates at which pituitary LH enters and leaves the intrafollicular fluid-filled spaces are substantially slower than those of peripheral blood. Two hours after LH-RH injection the levels of LH in plasma had increased from 1 to 200 ng/ml, whereas in the follicle the levels remained at approximately 2 ng/ml. Ten hours after the LH-RH injection, the levels of LH in plasma had returned to basal values (∼1·4 ng/ml) but in both small and large follicles the levels of LH (∼20 ng/ml) were comparable to those present in similar sized follicles 4 h earlier.
The data also indicate that more than 90% of the oestradiol produced by a large antral follicle (≥5 mm diameter) probably enters the bloodstream without first accumulating within the follicular antrum. Finally it is concluded that the clearance of the small amount of oestradiol which does accumulate in the follicular antrum is negligible compared with the clearance of this hormone from peripheral plasma.
SUBSTANTIAL AMOUNTS OF GONADOTROPHIN-LIKE MATERIALS IN SERA OF NORMAL SUBJECTS
Authors: PALA A. , MARINELLI G. , Di GREGORIO R. , SPAMPINATO G. , MORO M. , CARENZA L. 
Published: December 2008

Ultrafiltration of human sera resulted in increased levels of human chorionic gonadotrophin (hCG), LH and FSH measured by radioimmunoassay. The effect was greatly enhanced by chromatography of serum through Sepharose–protein A (which specifically binds immunoglobulin G) followed by ultrafiltration of the unretarded fractions.
Serum from a normally menstruating woman was treated by ultrafiltration and the retained fraction from 200 μl serum further chromatographed on a Sephadex G-150 Superfine column. The amounts of LH and FSH measured in the eluate by radioimmunoassay were higher by three orders of magnitude than those found in the untreated serum. Comparable amounts of hCG were also found in the eluate by two specific radioimmunoassays, and a value of 45 i.u. hCG was recovered in the eluate by bioassay.
Serum from another normally menstruating woman was applied to DEAE-cellulose and eluted stepwise using an elution gradient. The ultrafiltrate of one eluted fraction led to separation of a low molecular weight material which was able to neutralize the biological activity of a large dose of hCG.
The data support the hypothesis that substantial amounts of gonadotrophins are normally present in serum but that binding to inhibitors(s) prevents their assay in untreated sera.
EFFECT OF CHEMICAL SYMPATHECTOMY AND GANGLION BLOCKADE ON ANGIOTENSIN-STIMULATED FLUID ABSORPTION IN THE RAT JEJUNUM
Authors: DOREY P. G. , MUNDAY K. A. , PARSONS B. J. , POAT JUDITH A. , UPSHER MARY E. 
Published: December 2008

A study has been made of the effects of chemical sympathectomy and ganglion blockade on the responses of rat jejunum in vivo to intravenous doses of angiotensin and noradrenaline capable of stimulating fluid transport. Pretreatment with 6-hydroxydopamine (chemical sympathectomy) or pentolinium tartrate (ganglion blockade) abolished the stimulatory actions of angiotensin II but left the responses to noradrenaline unimpaired. Dopamine, like noradrenaline, stimulated fluid transport but this response required very high dopamine infusion rates, was refractory to the dopamine antagonist sulpiride and was inhibited by the α-blocker phentolamine.
The possible interaction between angiotensin and the intestinal sympathetics is discussed with reference to control of extracellular fluid volume.
SECRETION OF LUTEINIZING HORMONE IN OVARIECTOMIZED ADULT RATS TREATED NEONATALLY WITH MONOSODIUM GLUTAMATE
Authors: DYER R. G. , WEICK R. F. , MANSFIELD S. , CORBET H. 
Published: December 2008

We have studied the possible effects of monosodium glutamate (MSG) on LH secretion in ovariectomized rats.
In experiment 1 MSG-treated and control rats were given oestradiol benzoate at noon and 72 h later half the rats in each group were given a second injection of oestradiol benzoate or progesterone. Blood samples were taken immediately before and 6 h after these i.m. injections. At 78 h there were no significant differences in plasma LH concentration measured in the two groups of rats given progesterone or in the two groups given a second injection of oestradiol benzoate although for both MSG-treated and control rats progesterone produced a significantly (P < 0·01) greater LH surge than did oestradiol benzoate.
In experiment 2 100 μl blood samples were collected at 5-min intervals for up to 3 h from MSG-treated and control rats. For rats showing more than one pulsatile discharge of LH, peak and trough values for plasma LH concentrations were not significantly influenced by MSG treatment. However the mean pulse height was significantly (P < 0·001) greater in the MSG-treated group than in control rats. Pulsatile release stopped more quickly in the MSG-treated rats and their mean plasma LH concentration after 120 min of blood sampling was significantly (P < 0·05) lower than that obtained in the control animals.
Thus, although some aspects of LH secretion seem to be significantly different in MSG-treated rats, these effects may result from the greater sensitivity of the MSG-treated animals to experimental manipulation.
A COMPARISON OF PREPARATIONS OF HIGHLY PURIFIED HUMAN PITUITARY FOLLICLE-STIMULATING HORMONE: DIFFERENCES IN THE FOLLICLE-STIMULATING HORMONE POTENCIES AS DETERMINED BY IN-VIVO BIOASSAY, IN-VITRO BIOASSAY AND IMMUNOASSAY
Authors: STORRING P. L. , ZAIDI A. A. , MISTRY Y. G. , FRÖYSA BERIT , STENNING BRIDGET E. , DICZFALUSY E. 
Published: December 2008

The FSH potencies of 12 preparations of highly purified human pituitary FSH, originating from six different laboratories, were determined by in-vivo and in-vitro bioassays and by immunoassay in terms of the First International Reference Preparation of Human Pituitary Gonadotrophins (FSH and LH) for Bioassay (IRP; coded 69/104). The contamination of these FSH preparations with LH was also determined. Estimates of protein content were based on the absorbance at 280 nm of solutions of the preparations, assuming that A1%1 cm 280 = 10.
The FSH potencies varied between different preparations from 827 i.u./mg to 13 100 i.u./mg by in-vivo bioassay; from 2930 to 14 600 i.u./mg by in-vitro bioassay and from 1680 to 5690 i.u./mg by immunoassay. The ratios of in-vivo biological activity relative to in-vitro biological activity and to immunoreactivity respectively varied between preparations from 0·06 to 2·3 and from 0·15 to 4·1, and there was a significant positive correlation between each of these ratios and the in-vivo biological potency of the preparations; such differences could be due to varying degrees of sialylation between preparations. On the other hand the ratios of in-vitro biological activity to immunoreactivity between preparations were fairly constant (approx. 2). The excess biological activity relative to immunoreactivity observed, in terms of the IRP, in all these materials is consistent with recent findings of some immunoreactive FSH in the IRP unassociated with biological activity. These data did not demonstrate any significant advantage, in terms of FSH in-vivo biological potency, from the use of fresh-frozen rather than acetone-dried pituitary glands for the isolation of FSH.
Contamination of all these preparations with LH appeared to be less than 3% (w/w), as determined by in-vitro bioassay and by immunoassay.
The results of this study are discussed in relation to the selection of material for an international reference preparation for immunoassay and attention is drawn to the value of high in-vivo biological FSH potency as a criterion of the identity of a preparation as well as of its freedom from contaminants without FSH biological activity.
HYPOTHALAMIC SECRETION OF THYROTROPHIN RELEASING HORMONE IS DECREASED IN MALE JAPANESE QUAIL EXPOSED TO LONG DAILY PHOTOPERIODS
Authors: ALMEIDA O. F. X. 
Published: December 2008

Adult male Japanese quail held under short daily photoperiods (8 h light: 16 h darkness; 8L : 16D) had significantly higher plasma concentrations of thyroid-stimulating hormone (TSH), tri-iodothyronine (T3) and thyroxine (T4) than did those kept under long days (16L : 8D).
When given a single s.c. injection of 50 μg thyrotrophin releasing hormone (TRH) the birds held under both the 8L : 16D and 16L : 8D photoperiods showed rapid increases in their blood concentrations of TSH, T4 and T3, the amplitude of the TSH response of the birds exposed to 16L : 8D being particularly marked. These results suggest that, in the male quail, long daily photoperiods produce a hypothyroid state as a result of diminished TRH secretion. The synthetic and secretory capacities of the thyroid gland and pituitary thyrotrophs are apparently unimpaired by long days.
PITUITARY AND PLASMA LEVELS OF LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN MALE AND FEMALE RABBIT FETUSES
Authors: VEYSSIÈRE G. , BERGER M. , JEAN-FAUCHER CH. , DE TURCKHEIM M. , JEAN CL. 
Published: December 2008

To study the ontogenesis of fetal pituitary gonadotrophin synthesis and release, LH and FSH were measured by radioimmunoassay in fetal rabbit pituitary glands and blood of both sexes from day 18 of gestation until birth. Results on levels of testicular and plasma testosterone were also included. Immunoreactive LH was first detected on day 19 in the pituitary gland and on day 20 in the plasma of fetuses of both sexes. Pituitary FSH was first measurable in both male and female fetuses at 24 days of gestation. Levels of FSH could not be detected in the blood of male fetuses at any time during gestation. In females, FSH could be measured in the circulation from day 27 of gestation until birth.
These results show that (1) the ontogeny of pituitary LH and the onset of testosterone secretion are closely correlated and take place between 18 and 20 days of gestation just before the beginning of differentiation of the male genital tract, and (2) the highest concentrations of pituitary LH and FSH are observed, in both sexes, in late gestation after days 24–25.
Relationships among release of prolactin, synthesis of DNA and growth of the anterior pituitary gland of the rat: effects of oestrogen and sulpiride
Authors: Jahn G. A. , Machiavelli G. A. , Kalbermann L. E. , Szijan I. , Alonso G. E. , Burdman J. A. 
Published: December 2008

The effect of daily injections of sulpiride was compared with that of a single injection of the drug in male rats which had been treated with oestradiol diundecenoate for various periods of time. We studied the effect of the different treatments on weight of the pituitary gland, concentration of prolactin and incorporation of [3H]thymidine into DNA in the pituitary gland and on serum levels of prolactin. Administration of the oestrogen produced a marked increase in the synthesis of DNA at day 7. The stimulation diminished at day 21 and was not significant at day 45. The maximum increase in the concentration of prolactin in serum and pituitary glands was observed during the first 7 days (approximately 400 and 150% respectively) and in the weight of the anterior pituitary gland after 21 days of treatment (approximately 107%).
A single injection of sulpiride markedly stimulated the release of prolactin and the synthesis of DNA at day 7. Both these effects diminished at day 21 and disappeared by day 45. Daily injections of sulpiride also produced similar changes in the release of prolactin and in the replication of DNA. The growth of the anterior pituitary gland was greater in this group than in the rats which had been treated with oestradiol diundecenoate only. After the end of treatment with oestrogen and sulpiride the pituitary weight and the concentration of prolactin in the anterior pituitary gland diminished together with levels of prolactin and oestrogen in serum. There was a good correlation between weight of the gland and serum levels of prolactin. The results further support the idea of a mechanism which controls the proliferation of lactotrophs in which the release of the hormone is accompanied by an increase in pituitary DNA synthesis.
Daily variations in serotonin metabolism in the suprachiasmatic nucleus of the rat: influence of oestradiol impregnation
Authors: Héry M. , Faudon M. , Dusticier G. , Héry F. 
Published: December 2008

In order to determine the temporal relationships between variations in 5-hydroxy-tryptamine (5-HT, serotonin) metabolism in the suprachiasmatic nucleus (SCN) and the cyclic LH surge, and also to check whether implantation of oestradiol capsules might modulate 5-HT metabolism in the SCN, we carried out a parallel study of 5-HT content in the SCN and median eminence, and 5-HT metabolism in the SCN and supraoptic region in vitro. These experiments were performed on intact male rats, ovariectomized females and ovariectomized females implanted with oestradiol.
It was only in ovariectomized rats implanted with oestradiol, in which we have described the existence of a clear-cut circadian rhythm of LH secretion, that we found fluctuations in the content, synthesis and utilization of 5-HT. The content and synthesis were characterized by a peak between 12.00 and 15.00 h, whereas utilization was 50% higher at 09.00 and 19.00 h than at 15.00 h. These fluctuations in 5-HT content and metabolism were specific to the SCN; the median eminence and the supraoptic region did not show such variations. They were also specific to ovariectomized rats implanted with oestradiol, since the patterns of 5-HT content and metabolism in the SCN were the same in males and ovariectomized females and did not differ from those in the median eminence, the supraoptic region or the whole hypothalamus.
These results suggest that 5-HT terminals in the SCN play an important role in the control of cyclic LH secretion at a critical period. Moreover, oestradiol seems to be partly responsible for the fluctuations of 5-HT metabolism in the SCN of ovariectomized rats implanted with oestradiol.
Hypothalamic, pituitary and uterine cytoplasmic and nuclear oestrogen receptors and their relationship to the serum concentration of tamoxifen and its metabolite, 4-hydroxytamoxifen, in the ovariectomized rat
Authors: Bowman S. P. , Leake A. , Morris I. D. 
Published: December 2008

High-affinity oestrogen receptors were measured in the cytosol and nuclei prepared from the hypothalamus, pituitary gland and uterus of the ovariectomized rat up to 16 days after a single dose of tamoxifen or 4-hydroxytamoxifen. Tamoxifen produced a dose-related fall in the concentration of cytosol receptors in the hypothalamus, pituitary gland and uterus. Minimum values were observed after 24 h; cytosol receptor concentrations were restored slowly and only reached expected control values between 4 and 8 days and 2 and 4 days for 7·0 mg/kg and 0·7 mg/kg doses of tamoxifen respectively. The nuclear receptor changes were inversely related to the cytosol receptor changes, except that hypothalamic nuclear receptor concentrations after 0·7 mg tamoxifen/kg were not changed. 4-Hydroxytamoxifen (0·14 mg/kg) depleted cytosol and raised nuclear oestrogen receptors in the pituitary gland and uterus. Receptor concentrations had returned to the expected control values by day 4. Oestrogen receptor concentrations in the hypothalamus were unchanged. The apparent resistance of the receptor system in the hypothalamus to translocation by tamoxifen and 4-hydroxytamoxifen was probably due to the blood–brain barrier since the apparent affinity of tamoxifen for the cytosol receptor was similar for all three tissues (dissociation constant 4 nmol/l).
Serum concentrations of tamoxifen and 4-hydroxytamoxifen measured after a single dose of 7·0 mg tamoxifen/kg were maximal after 24 h and undetectable by 4 days, at which time nuclear and cytosol receptor levels were still changed. Concentrations of 4-hydroxy-tamoxifen were approximately one-third those of tamoxifen. The results suggest that the receptor changes after tamoxifen are not simply related to the serum concentration of tamoxifen and its metabolites and that the retention of ligand within the target tissue may be an important determinant.
Ovarian steroid concentrations in rats with spontaneous and with delayed or advanced ovulation
Authors: Toorop A. I. , Gribling-Hegge L. , Meijs-Roelofs H. M. A. 
Published: December 2008

The present study examined the ovarian progesterone levels in rats during the normal 5-day oestrous cycle and in rats with an experimentally induced delayed or advanced ovulation. Ovarian androgen and oestrogen concentrations were also studied in rats with an advanced ovulation.
The ovarian progesterone concentrations during the normal cycle showed two peaks: one during metoestrus and dioestrus 1 and the second during the afternoon of pro-oestrus.
Rats treated with pentobarbitone sodium (35 mg/kg body weight) at 13.00 h on the day of pro-oestrus showed no increase in ovarian progesterone levels on that day, but did show an increase during the afternoon of the next day.
Rats injected intraperitoneally with an ovulation-inducing bolus of human chorionic gonadotrophin (hCG; 20 i.u.) at 15.00 h on the day before pro-oestrus (dioestrus 2) showed increased ovarian progesterone levels as early as 0·5 h after hCG injection. Lowered levels of ovarian androgen and oestrogen values compared with saline-injected rats were first found 2 and 6 h respectively after hCG injection.
In conjunction with data obtained previously these findings show that normal, delayed and advanced ovulations are preceded by an increase in ovarian progesterone concentrations and a subsequent decline in ovarian androgen and oestrogen levels.