bluuebunny/crossref_metadata_2025_split huggingface dataset:
PLASMA CONCENTRATION OF TESTOSTERONE IN YOUNG BULLS IN RELATION TO AGE, RATE OF WEIGHT GAIN AND STIMULATION WITH HUMAN CHORIONIC GONADOTROPHIN
Authors: SUNDBY ANNE , VELLE WEIERT 
Published: December 2008

In 86 bulls ranging in age between 3 and 11 months, the maximal plasma testosterone concentration (n = 7) well as the mean concentration (n = 7, same samples) were found to increase with age to peak values at 7–8 months with a subsequent decrease.
The multiple correlation coefficient for monthly gain as a function of testosterone concentration and age was 0·85 (P <0·001), for monthly gain as a function of age 0·84 (P <0·001) and for monthly gain as a function of testosteroneconcentration 0·44 (P <0·001).
The deviation in levels of measured plasma testosterone from the curve expressed by multiple regression analyses of testosterone concentration as a function of age was correlated with the average daily weight gain during the testing period of 9 months and found to be not significant (r = 0·21).
The difference between concentrations of plasma testosterone after stimulation with human chorionic gonadotrophin (HCG) and the spontaneous maximal concentration of this hormone was not significant. High correlation coefficients were found between maximal (r = 0·8) and mean (r = 0·6) concentrations of plasma testosterone before and after an injection of HCG (P <0·001).
EFFECTS OF TRI-IODOTHYRONINE, THYROXINE AND ISOPROPYL-DI-IODOTHYRONINE ON THYROID-STIMULATING HORMONE IN SERUM AND PITUITARY GLAND AND ON PITUITARY CONCENTRATIONS OF PROLACTIN, GROWTH HORMONE, LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN HYPOTHYROID RATS
Authors: WONG C. C. , DÖHLER K. -D. , VON ZUR MÜHLEN A. 
Published: December 2008

Replacement of the 3′-halogen of the tri-iodothyronine (T3) molecule by a propyl-group produces a thyromimetic analogue, 3′-isopropyl-3,5-di-iodo-l-thyronine (T2iPr), with high biological potency. A serum thyroid-stimulating hormone (TSH) suppression test with one single intraperitoneal injection of 3 or 30 nm-T3 or T2iPr or with 30 or 300 nm-thyroxine (T4) per kg body weight was performed on 56 adult male Lewis rats which were maintained for 3 weeks on an iodine-deficient diet containing 0·2% 6n-propyl-2-thiouracil (PTU). Blood was withdrawn from each rat by cardiac puncture 24 h before and 3, 7, 24 and 48 h after application of the iodothyronines.
Raised serum levels of TSH, due to the treatment with PTU, were significantly reduced within 3 h of treatment with 30 nm-T3, 300 nm-T4, 3 or 30 nm-T2iPr and they remained low throughout the observation period. Treatment with 3 nm-T3 or 30 nm-T4 per kg body weight was less effective. Pituitary concentrations of growth hormone, TSH, prolactin and FSH were significantly reduced by the treatment with PTU. There was also a slight, but insignificant reduction of pituitary concentrations of LH. Treatment with T3, T4 or T2iPr stimulated the reaccumulation of growth hormone, TSH, prolactin, LH and FSH in the pituitary gland.
ALTERATIONS INDUCED BY CLOMIPHENE IN THE CONCENTRATIONS OF OESTROGEN RECEPTORS IN THE UTERUS, PITUITARY GLAND AND HYPOTHALAMUS OF FEMALE RATS
Authors: ADASHI E. Y. , HSUEH A. J. W. , YEN S. S. C. 
Published: December 2008

Alterations in the concentrations of oestrogen receptors in the uterus, pituitary gland and hypothalamus during the 2 weeks following a single administration of clomiphene citrate (Clomid) to immature, bilaterally ovariectomized rats were investigated. Examination of the uterine wet weight at 1, 7 and 14 days following a single injection of Clomid (100 μg, 250 μg or 10 mg) indicated significant time- and dose-related increments from a control value of 45 ± 2 (s.e.m.) mg to a maximum of 123 ± 3 mg (250 μg dose at 14 days). In contrast, a single injection of oestradiol led to a transient increase in the uterine weight on day 1 to 94 ± 6 mg, but was without effect by days 7 and 14. Analysis of the uterine DNA content 7 and 14 days after treatment with Clomid revealed significant increments from control values of 390 ± 10 μg to a high level of 558 ± 8 μg (10 mg dose at 7 days). There was a transient retention of nuclear oestrogen receptors and rapid replenishment of cytoplasmic oestrogen receptors in less than 24 h in the uteri of animals treated with oestradiol (25 μg), but determinations of receptor content in Clomid-treated animals revealed prolonged retention of nuclear receptors and delayed replenishment of cytoplasmic receptors. The duration and extent of retention of nuclear receptors and depletion of cytoplasmic receptors after treatment with Clomid were found to be dose-dependent. Fourteen days after Clomid treatment, levels of oestrogen receptors in nuclei from the uterus were still raised in all treatment groups, whereas replenishment of cytoplasmic receptors was complete in animals treated with the lower doses (100 and 250 μg) of Clomid.
A single injection of Clomid (250 μg) induced similar prolonged retention of nuclear receptors and delayed depletion of cytoplasmic receptors in pituitary tissue. In contrast, changes in the content of oestrogen receptors in the hypothalamus following Clomid treatment were minimal. The limited effect of Clomid on hypothalamic tissue may mean that the pituitary gland is a more important target for this compound than is the hypothalamus. The findings have confirmed earlier reports on the long-term uterotrophic effect of Clomid and have suggested that under these long-term, in-vivo conditions, Clomid acts in the uterus and pituitary gland as a long-acting oestrogen characterized by prolonged retention of oestrogen receptors in the nucleus and delayed, but otherwise effective, replenishment of the oestrogen receptors in the cytoplasm.
EFFECT OF SUPPRESSION OF THE SURGE OF FOLLICLE-STIMULATING HORMONE WITH PORCINE FOLLICULAR FLUID ON FOLLICULAR DEVELOPMENT IN THE RAT
Authors: HIRSHFIELD ANNE N. , DE PAOLO L. V. 
Published: December 2008

To examine the manner in which the FSH surge of one oestrous cycle recruits follicles for ovulation in the subsequent cycle, porcine follicular fluid (PFF) was used to alter the pattern of endogenous FSH secretion during the periovulatory period. Ovaries of animals killed at oestrus or metoestrus were examined histologically for the presence of large follicles (greater than 400 μm in diameter) after treatment. Large follicles were absent in ovaries of all PFF-treated animals at oestrus, while control rats had an average of 2·7 large follicles per ovary. By metoestrus, however, ovaries of rats treated with PFF contained several large, healthy follicles. Only when PFF treatment was continued throughout the evening of oestrus was the appearance of large follicles prevented at metoestrus.
Our results suggest that the prolonged oestrous portion of the FSH surge, rather than the pro-oestrous portion, is responsible for follicular recruitment during the normal oestrous cycle in the rat. They also indicate that compensatory follicular development occurs in response to the FSH rebound which has been shown to follow FSH suppression.
SPECIFIC BINDING OF THYROID-STIMULATING HORMONE BY HUMAN SERUM GLOBULINS
Authors: BÍRÓ J. 
Published: December 2008

Globulin preparations (41) from patients with Graves's disease (positive to thyroid stimulating immunoglobulins; TSI) and 12 from healthy persons (TSI-negative) were tested for their specific thyrotrophin (TSH)-binding properties. Globulins from both groups possessed binding sites for 131I-labelled TSH. The mean dissociation constant (Kd) was 6·8 pmol/l per mg globulin and the maximum specific binding (Bmax) was 3·0 pmol/mg globulin per 1 for the TSI-negative control group. Twenty-four (58·5%) globulin preparations from the TSI-positive group had similar TSH-binding characteristics with mean Kd of 7·2 pmol/l per mg globulin and Bmax of 3·6 pmol/mg globulin per 1 (A-type binding) but the remaining 17 (41·5%) bound TSH in a different fashion with Kd of 71·5 pmol/l per mg globulin and Bmax of 13·6 pmol/mg globulin per 1 (B-type binding).
Both types of specific TSH binding reached the maximal level within 1 h of incubation and had an optimum pH of 7–8. There was a linear correlation between the amount of bound TSH and the globulin content of the samples. Both types of binding were reversible by the addition of an excess of TSH and gonadotrophins, ACTH, prolactin and insulin competed with TSH for the binding sites only when in relatively high concentrations. The binding sites were associated with macromolecules; they emerged with the void volume after chromatography on Sephadex G-200 and migrated with immunoglobulin G (IgG) on paper electrophoresis. The binding capacity of the globulin preparations could be decreased by preincubation with antiserum to human IgG or with human thyroid membranes.
A ROLE FOR PROSTAGLANDINS IN DECIDUALIZATION OF THE RAT UTERUS
Authors: SANANÈS NICOLE , BAULIEU ETIENNE-EMILE , LE GOASCOGNE CLAUDE 
Published: December 2008

The deciduogenic action of various kinds of prostaglandin (PG), i.e. PGE1, PGE2, PGF2α and PGI2, methylated prostaglandins (15-met-PGE1, 15-met-PGE2 and 15-met-PGF2α), PGF2α-13-dehydro analogues (13-DH-PGF2α, ent-15-epi-13-DH-PGF2α), endoperoxide analogues (15S)-hydroxy-9α,11α-(epoxymethano)-prosta-5Z,13E-dienoic acid (U 44069) and (15S)-hydroxy-11α,9α-(epoxymethano)-prosta-5Z,13E-dienoic acid (U 46619), and of the prostaglandin precursor, arachidonic acid, has been demonstrated after intraluminal instillation of these compounds into the uterus of immature rats sensitized with progesterone alone. Under this minimal hormonal stimulation, in which a trauma (a scratch) of the endometrium is required to induce the decidual response, all these compounds elicited the formation of deciduomata, substantiating the suggestion that the scratch-induced decidual reaction is mediated through release of prostaglandin. Confirmation was obtained through the effect of indomethacin and cortisol, both of which decreased the decidual response brought on by a scratch or by arachidonic acid, whereas the effect of PGF2α was decreased by indomethacin but not by cortisol. Histamine, thromboxane B2, and oleic, palmitic and homo-γ-linolenic acids were not deciduogenic.
A dose-dependent inhibitory effect of indomethacin on deciduoma formation by instillation of oil into animals sensitized by progesterone plus oestradiol was also observed.
The results support the proposal that the decidual reaction involves prostaglandins and we suggest that the deciduoma is a valuable model for studying the action of prostaglandin-related compounds.
CONCENTRATIONS OF OESTRADIOL AND OESTRONE IN PLASMA, UTERUS AND OTHER TISSUES OF FETAL GUINEA-PIGS: THEIR RELATIONSHIP TO UPTAKE AND SPECIFIC BINDING OF [3H]OESTRADIOL
Authors: GELLY C. , SUMIDA C. , GULINO A. , PASQUALINI J. R. 
Published: December 2008

The concentrations of unconjugated oestradiol-17β and oestrone have been measured by radioimmunoassay in the plasma of fetal, newborn and immature guinea-pigs. In fetal plasma, the values of oestradiol ranged from 15 to 50 pg/ml with no significant variations with gestational age except for an abrupt increase at the very end of gestation (148 pg/ml). Low concentrations of oestradiol were also found postnatally (from not detectable to 31 pg/ml) as well as in maternal plasma (22 pg/ml). The values of oestrone were consistently higher in all plasma regardless of age (43–164 pg/ml).
Oestrogen concentrations were also determined in the fetal uterus, lung, kidney and brain and were found to be as much as 60 times higher (per g tissue) than in plasma, especially in the fetal uterus which contained four to five times more than the other tissues. These data correlated well with a 20–90 times greater uptake of [3H]oestradiol by the fetal uterus compared with the other tissues after in-vivo administration of [3H]oestradiol to the fetuses. The selective retention of oestradiol was probably due to the presence of specific oestradiol binding in these fetal tissues, particularly in the uterus whose binding was 60–120 times higher than in the other fetal tissues. Thus, the levels of oestrogen in the circulation of fetal guinea-pigs are low, but the fetal uterus is capable of maintaining a higher concentration which may be important physiologically since oestradiol has been shown to evoke a biological response in the fetal guinea-pig uterus.
ULTRASTRUCTURE AND IMMUNOCYTOCHEMISTRY OF THE PARS DISTALIS OF THE FEMALE RAT WHEN GRAFTED UNDER THE KIDNEY CAPSULE AND A PARALLEL STUDY OF THE PLASMA LEVELS OF PROLACTIN
Authors: AGUADO L. I. , ALVIAL G. S. , RODRÍGUEZ E. M. 
Published: December 2008

Two hypophysial partes distales were grafted under the kidney capsule of intact female rats. The plasma prolactin levels 15, 45 and 90 days after the operation were determined. At the same postoperative intervals the grafted glands of some of the operated rats were processed for conventional light and electron microscopy and for the demonstration of prolactin, FSH and LH according to the unlabelled immunoperoxidase procedure. The ultrastructural characteristics of the transplanted secretory cells and the amount and distribution of the immunoreactive material within their cytoplasm were used to evaluate approximately the secretory activity of these cells.
Although levels of prolactin in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in 71% of the samples taken 45 days after operation. At day 15 the graft was completely surrounded by lymphoid cells whereas at day 45 these cells had invaded the whole graft. In the group sampled at day 90 the graft was free of lymphoid cells. When traced immunocytochemically the three types of cells followed different patterns of evolution after transplantation. Most prolactotrophs were hypertrophied in all groups but, in addition, they underwent a process leading to hyperplasia some time between days 45 and 90 after operation. Syncytial formations which probably correspond to multinucleated prolactotrophs were present only in the group sampled at day 90. The number of LH and FSH cells had decreased in the group at day 45 and by day 90 the former remained scarce but immunoreactive FSH cells were no longer found. At the ultrastructural level clear signs of involution of gonadotrophs and degradation by macrophages were seen in the graft 45 days after operation.
The relation between the morphology and hormone content of the graft and hormone content of the plasma is discussed, together with several questions raised by the results. Pituitary transplantation can be used as an experimental model only if the time-dependent changes described here are taken into account.
CONCENTRATIONS OF PITUITARY, GONADAL AND ADRENAL HORMONES IN SERUM OF LAYING AND BROODY WHITE ROCK HENS (GALLUS DOMESTICUS)
Authors: BEDRAK E. , HARVEY S. , CHADWICK A. 
Published: December 2008

Diurnal variations in circulating concentrations of LH, GH, prolactin, corticosterone, oestradiol, progesterone and testosterone were followed in laying and broody White Rock domestic fowl. Throughout the 24 h study prolactin concentrations in serum were consistently (two- to fourfold) higher in broody than in laying birds, in which the prolactin level varied with the light: darkness or ovulatory cycles. Concentrations of GH in serum tended to be lower in broody birds but in both groups were very variable and showed no obvious relationship with either the lighting or ovulatory cycles. Broodiness was also characterized by low LH and gonadal steroid levels and by the absence of preovulatory peaks in the serum concentrations of these hormones. A diurnal rhythm in corticosterone was observed in both the laying and broody birds, with high levels during the period of darkness. Corticosterone concentrations were markedly higher in the broody birds than in laying birds during most of the 24 h study. No diurnal rhythm in the blood haematocrit level was observed in either group, although the level was generally lower in broody birds. This difference, however, was insufficient to account for the lower LH and gonadal steroid levels in the broody birds.
The results suggest that prolactin is involved in the initiation or maintenance of broodiness in the fowl and the possibility of an antigonadal role for the hormone is discussed.
SPECIFIC PROLACTIN BINDING IN THE RAT ADRENAL GLAND: ITS CHARACTERIZATION AND HORMONAL REGULATION
Authors: CALVO J. C. , FINOCCHIARO L. , LÜTHY I. , CHARREAU E. H. , CALANDRA R. S. , ENGSTRÖM B. , HANSSON V. 
Published: December 2008

Rat adrenal prolactin receptors possess the same hormonal specificity as those in the prostate gland and liver, but are less stable during storage and after freezing. There is a gradual decrease in specific prolactin binding to the adrenal during sexual maturation in male rats; maximum binding capacity of 980 fmol/mg protein is at 25 days of age decreasing to approximately 100 fmol/mg protein at day 90. Prolactin receptors in the prostate are high at 25 days of age (700 fmol/mg protein), decrease sharply by day 30 (180 fmol/mg protein) and then gradually increase.
Ovariectomy resulted in a significant rise in total prolactin binding in the adrenal gland, while the administration of oestradiol or testosterone reduced the binding, the reverse of changes in prolactin binding in the liver. Only oestrogen increased serum levels of prolactin in female rats.
Ovine prolactin (500 μg) given to female rats resulted in a rapid increase over a period of 2–8 h in total prolactin receptors in the adrenal, and these then decreased to normal levels, indicating a possible positive regulation of prolactin receptors by homologous hormone.
STEROIDALINTERACTIONS IN THE REGULATION OF MATERNAL BEHAVIOUR IN VIRGIN FEMALE RATS: EFFECTS OF TESTOSTERONE, DIHYDROTESTOSTERONE, OESTRADIOL, PROGESTERONE AND THE AROMATASE INHIBITOR, 1,4,6-ANDROSTATRIENE-3,17-DIONE
Authors: BRIDGES R. S. , RUSSELL D. W. 
Published: December 2008

The effects of exposure to concentrations of androgens, oestradiol (OE2) and progesterone similar to those found during pregnancy on the induction of maternal behaviour were investigated in female rats. In the first experiment the effects of testosterone and dihydrotestosterone (DHT) administered in combination with progesterone (using silicone elastomer capsules) on the induction of behavioural responsiveness towards young (crouching, retrieval and grouping of pups) were measured in ovariectomized virgin rats. Hormonally treated animals were exposed to testosterone or DHT from day 1 of treatment to the end of behavioural testing, while progesterone was administered for 10 days (days 3–13). Testing for maternal responsiveness began on day 14 and lasted until day 23. Significant reductions in latencies to show individual aspects of and complete maternal behaviour were found only in animals treated with a combination of testosterone and progesterone (range of mean latencies for showing one aspect of, to complete, maternal behaviour = 1·0–1·4 days). The mean latencies of the other hormonally treated animals ranged from 5 to 6 days and were similar to those of non-hormonally treated control rats.
The second experiment examined the possibility that stimulation of maternal behaviour in animals given testosterone and progesterone resulted from the aromatization of testosterone to OE2. Ovariectomized virgin rats were implanted with capsules containing testosterone and others with the aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD) on day 1, and with progesterone capsules on day 3. Progesterone capsules were removed on day 13 and behavioural testing commenced on day 14. Treatment with testosterone and progesterone failed to stimulate maternal behaviour in rats treated with ATD.
In a third study ovariectomized virgin rats were implanted with OE2 on day 1 and progesterone on day 3. The progesterone implants were removed on day 13 and testing began on day 14. Significant reductions in latencies to show all aspects of maternal behaviour were found in these rats.
In a final study progesterone capsules remained in OE2- and progesterone-treated rats from day 3 until the completion of behavioural testing. The presence of progesterone implants throughout the test period (days 14–23) blocked the rapid onset of maternal responsiveness induced by removal of progesterone on day 13 shown in rats treated with OE2 plus progesterone in experiment 3. These data suggest that during gestation testosterone, through its conversion to OE2, synergizes with progesterone to help stimulate the development of the capacity of the female animal to respond maternally to young, a capacity unmasked by withdrawal of progesterone before parturition.
DYNAMICS OF THE FORMATION AND RELEASE OF CORTICOTROPHIN RELEASING ACTIVITY BY THE RAT HYPOTHALAMUS IN VITRO
Authors: GILLHAM B. , BECKFORD URSZULA , INSALL R. L. , SKELLY A. MCL. , JONES M. T. 
Published: December 2008

The ability of the isolated rat hypothalamus, incubated in vitro, to form and secrete corticotrophin releasing factor (CRF) has been assessed. It was found that serotonin (10 ng/ml), when added to the hypothalamus in vitro, caused the release of CRF and an increase in the activity of CRF contained in the tissue. The activity of CRF was estimated by its ability to cause the secretion of ACTH (determined by the cytochemical assay procedure) from anterior pituitary fragments in vitro. Provided a minimum of 10 min 'rest' in serotonin-free medium was allowed between each challenge with the neurotransmitter, the response of the hypothalamus in vitro was maintained for at least 3 h. A detailed examination of the time-course of CRF formation and secretion following a single addition of serotonin showed that the release was well underway within 40 s and continued up to 4 min, but then ceased. On the other hand, the tissue content of CRF was found to be reduced significantly at 20 and 40 s, had returned to basal values at 1 min and continued to increase to reach a maximum at 4 min that was maintained at 6 min. The stimulated release was approximately six times greater than basal and the increase in content approximately ten times basal. Removal of the serotonin-containing medium after 6 min of stimulation was accompanied by a precipitous fall in the CRF contained in the tissue and this was significant 2 min later with CRF content back to basal levels within 4 min. The serotonin-induced increase in CRF content was shown to be greatest in the area of the ventral portion of the medial basal hypothalamus containing the median eminence and its attendant pituitary stalk.
The energy metabolite status of the hypothalamus in vitro under the conditions employed to cause the secretion of CRF was assessed. The rates of oxygen consumption and release of lactate, and the tissue concentrations of K+ and ATP were all determined and found to be comparable to values published for more conventional cerebral slice preparations for up to 2 h in vitro. At 3 h a fall in tissue K+ and an increase in the amount of lactate released into the medium suggested that the preparation was showing signs of becoming compromised metabolically and this trend was more obvious at 4 h when the ATP level had also fallen significantly.
In more limited cognate experiments the changes in ACTH formation and release induced in anterior pituitary fragments in vitro by the addition of hypothalamic extracts were studied. Once again the release of the hormone was accompanied by an increase in the ACTH content of the tissue. The increase in content reached a maximum by 10 min and then declined to basal levels within 10 min of removal of the CRF-containing medium. Thus, it is possible that degrading enzymes play an important role in the control of hormonal output from both tissues.