THE EFFECTS OF ARGININE VASOTOCIN ON PREGNANT MARE'S SERUM-INDUCED OVULATION IN THE IMMATURE FEMALE RAT

1978 ◽  
Vol 87 (2) ◽  
pp. 367-376 ◽  
Author(s):  
Linda Y. Johnson ◽  
Mary K. Vaughan ◽  
Russel J. Reiter ◽  
David E. Blask ◽  
P. Kevin Rudeen
Keyword(s):  
Arginine Vasotocin ◽  
Female Rats ◽  
Maximum Plasma ◽  
Female Rat ◽  
Immature Female ◽  
Ovarian Weight ◽  
Induced Ovulation ◽  
Early Rise

ABSTRACT Arginine vasotocin (AVT) treatment (1 μg/injection) every two hours beginning at 06.00 h on the morning preceding expected ovulation significantly inhibited ovulation in 29-day-old immature female rats treated 2 days earlier with 30 IU of PMS. Pre-ovulatory plasma surges and pituitary decreases in LH, FSH and prolactin as measured by radioimmunoassay were not eliminated by AVT treatment. However, there appeared to be an early rise in plasma FSH in these rats and the maximum plasma LH value attained during the surge period in PMS-treated rats was elevated by AVT treatment. Arginine vasotocin significantly inhibited the increase in ovarian weight which occurs in PMS-treated rats on the day preceding ovulation and uterine weights were consistently depressed in AVT-treated rats. The results of this study indicate that AVT likely inhibits PMS-induced ovulation at the level of the ovary, although the possibility cannot be ruled out that inhibition resulted from the advancement of the plasma FSH rise. These data and other studies investigating the effects of AVT on reproduction indicate that AVT is possibly capable of acting at more than one level of the hypothalamo-hypophyseal-gonadal axis.

IN-VITRO STUDIES OF THE EFFECTS OF OESTROGEN PRETREATMENT ON THE SENSITIVITY OF THE IMMATURE FEMALE RAT PITUITARY GLAND TO STIMULATION WITH GONADOTROPHIN RELEASING HORMONE

1977 ◽  
Vol 74 (1) ◽  
pp. 11-21 ◽  
Author(s):  
M. WILKINSON ◽  
D. DE ZIEGLER ◽  
DANIELLE CASSARD ◽  
K. B. RUF
Keyword(s):  
Pituitary Gland ◽  
Brain Lesion ◽  
Culture Technique ◽  
Female Rats ◽  
Female Rat ◽  
Immature Female ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Unilateral Brain Lesion

The effects of oestrogen priming on the sensitivity of the anterior pituitary gland to stimulation with gonadotrophin releasing hormone (GnRH) was investigated in immature female rats using a new organ culture technique. Hemipituitary glands obtained from animals primed with a single dose of oestradiol benzoate (OB; 20 μg/100 g body weight) released significantly more LH when pulsed with GnRH (4 nmol/l) than did control hemipituitary glands. This potentiating effect was detectable as early as 5 days after birth. After a second stimulation, LH secretion remained high. These results were compared with those obtained from animals treated to induce increased levels of endogenous oestrogen on day 26 of life. Thus, hemipituitary glands were obtained from animals given two injections of OB, an injection of pregnant mare serum gonadotrophin (PMSG) or a unilateral brain lesion placed in the basal hypothalamus. Pituitary tissue was stimulated as before with a pulse of GnRH. Two injections of OB enhanced the sensitivity to stimulation. Conversely, both PMSG and lesion treatment severely reduced the sensitivity to GnRH, although PMSG-treated and lesioned animals have been used as models for the study of ovulation.

ANTERIOR PITUITARY SENSITIVITY IN IMMATURE FEMALE RATS STIMULATED WITH GONADOTROPHIN RELEASING HORMONE IN VIVO: EFFECT OF PRIMING WITH OESTROGEN, PREGNANT MARE SERUM GONADOTROPHIN OR BRAIN LESION

1977 ◽  
Vol 74 (1) ◽  
pp. 99-109 ◽  
Author(s):  
D. DE ZIEGLER ◽  
M. WILKINSON ◽  
DANIELLE CASSARD ◽  
K. B. RUF
Keyword(s):  
Brain Lesion ◽  
Treated Group ◽  
Female Rats ◽  
Similar Degree ◽  
Female Rat ◽  
Immature Female ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Pregnant Mare Serum Gonadotrophin

An investigation of pituitary sensitivity, assessed in terms of increments in plasma LH and FSH concentrations, to stimulation with one or two injections of gonadotrophin releasing hormone (GnRH) was carried out on 26-day-old immature female rats which had received one of the following priming treatments: 10 μg oestradiol benzoate (OB) as a single injection on day 23 or day 25, or on both days; 10 i.u. pregnant mare serum gonadotrophin (PMSG) on day 24; an electrochemical brain lesion placed in the mediobasal hypothalamus on day 23; control animals received either vehicle alone or a sham lesion. Pituitary sensitivity assessed at 10.00 h on day 26, after one or two injections of GnRH (100 ng/100 g body weight, s.c.), was enhanced to a similar degree in the three groups treated with OB in terms of LH (P < 0-01). The FSH response also increased after OB treatment but was not statistically significant. In contrast, 48 h after the injection of PMSG (i.e. when the rats were in a 'pro-oestrous-like' condition) pituitary sensitivity in terms of both LH and FSH dropped sharply (P < 0·001). In lesioned animals, pituitary sensitivity to one injection of GnRH was unchanged. A second GnRH injection administered after a 60 min interval induced a slightly larger LH response in control animals. In contrast, the ratio of the second response to the first increased in animals treated with PMSG, despite the state of overall decrease in sensitivity, being 4·5:1 in PMSG-treated rats versus 1·4:1 in controls. In a second set of experiments, we investigated the variation of pituitary sensitivity in conjunction with an experimentally induced gonadotrophin surge. In animals treated with OB on day 23 and with 1 mg progesterone at 12·00 h on day 26, pituitary sensitivity was increased at both 14.00 and 17.00 h as compared with that in the day 23 OB-treated group at 10.00 h. The PMSG-treated animals maintained their state of decreased responsiveness at 14.00 h, but exhibited increased pituitary sensitivity at the time of the gonadotrophin surge (17.00 h). These results show that OB increases pituitary sensitivity to GnRH in 26-day-old female rats and that the induction of a gonadotrophin surge further increases this sensitivity. In contrast, PMSG-treated rats displayed a state of decreased responsiveness 48 and 52 h, but not 55 h, after the injection. Pituitary sensitivity on the second day after PMSG treatment thus clearly differs from that observed during pro-oestrus in the adult cyclic female rat.

Effects of acute administration of 2-hydroxylated metabolites of oestrogens on LH and prolactin secretion in male and female prepubertal rats

1984 ◽  
Vol 103 (3) ◽  
pp. 317-325
Author(s):  
A. K. Brar ◽  
G. Fink
Keyword(s):  
Plasma Concentration ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Female Rat ◽  
Uterine Weight ◽  
Immature Female ◽  
Male And Female ◽  
Immature Male ◽  
Lh Release

ABSTRACT The effects of catechol oestradiol and catechol oestrone on the release of LH and prolactin were investigated in immature male and female Wistar rats. In male rats both catechol oestradiol and catechol oestrone significantly increased the plasma concentration of LH, and catechol oestradiol but not catechol oestrone significantly increased the plasma concentration of prolactin and decreased the pituitary concentration of LH. The parent oestrogens, oestradiol-17β and oestrone, had no effect on plasma LH concentrations, but both increased significantly the plasma concentration of prolactin, and oestrone but not oestradiol-17β increased the pituitary concentration of LH. In immature female rats, catechol oestradiol inhibited the surge of LH and the increase in uterine weight induced by injecting pregnant mare serum gonadotrophin (PMSG). The injection of oestrone induced an increase in the plasma concentration of LH which was about nine times greater than that produced by oestradiol-17β. There were no significant differences in the effects of these steroids on plasma prolactin concentration. These results (i) confirm that in the immature male rat catechol oestrogens can stimulate LH release and show that catechol oestradiol can increase prolactin release, (ii) show that catechol oestradiol can inhibit the stimulatory effects of PMSG on LH release and uterine weight in the immature female rat, and (iii) demonstrate that oestrone can stimulate LH release in the immature female rat. J. Endocr. (1984) 103, 317-325

Initial ovulation rate and follicle population after injection of inhibin-neutralizing antiserum in the late-prepubertal rat

1991 ◽  
Vol 130 (2) ◽  
pp. 289-296 ◽  
Author(s):  
H. J. Sander ◽  
H. M. A. Meijs-Roelofs ◽  
E. C. M. van Leeuwen ◽  
P. Kramer ◽  
W. A. van Cappellen
Keyword(s):  
Neutralizing Antibodies ◽  
Ovulation Rate ◽  
Female Rats ◽  
Corpora Lutea ◽  
Female Rat ◽  
Follicle Growth ◽  
Immune Control ◽  
Immature Female ◽  
Antral Follicles ◽  
Control Serum

ABSTRACT In late-prepubertal female rats passive immunoneutralization of endogenous inhibin was achieved by injection of inhibin antiserum. Effects on follicle population, timing of sexual maturation, ovulation rate at first and second oestrus and serum FSH levels were studied. Rats were injected with antiserum, (non-immune) control serum from castrated sheep (castrated serum) or their IgG fractions, or with saline on day 33 or 3 or 2 days (days −3/−2) before the expected day of first ovulation, day 38·5±0·2 (n = 70). Blood was collected from different subgroups at 8, 24 and 48 h, and at first and second oestrus after injection. At necropsy, ovaries were histologically prepared for differential counting of follicles (48 h and first oestrus) and counting of corpora lutea (CL; first and second oestrus) as an index of ovulation rate. Results from rats injected with either serum or its IgG fraction were not different, as was the case when rats were injected with either castrated serum or saline. Thus, results from groups treated with antiserum and antiserum IgG were combined and labelled 'antiserum', and the castrated serum, castrated serum IgG and saline-treated groups were combined and labelled 'control'. The activity of inhibin-neutralizing antibodies in the circulation of antiserum-treated rats was reduced by 43% between 8 h and second oestrus after injection, as determined by the binding of purified bioactive radioiodinated 31 kDa bovine inhibin. After antiserum injection on day 33, more healthy antral follicles (vol. > 100 × 105 μm3, diameter > 260 μm) were present in the ovaries at 48 h (70·6 vs 54·4; P < 0·05) and at first oestrus (73·1 vs 50·8; P < 0·05) if first oestrus was reached within 5 days, but numbers were not different if first oestrus was more than 5 days after injection (52·6 vs 50·8). The number of CL after injection of antiserum on day 33 was increased at first oestrus compared with control (13·4±0·5, n = 30, vs 10·0±0·2, n = 40; P<0·001), an effect that was even more clearly present in antiserum-injected rats ovulating within 5 days (14·4±0·7, n = 20; P < 0·001). Rats injected with antiserum at days −3/−2 showed a doubling of ovulation rate at first oestrus when compared with control animals (21·5±0·8, n = 12, vs 10·5±0·2, n = 15; P < 0·001). No differences in the number of CL was seen at second oestrus. Age and body weight on the day of first ovulation were not influenced by antiserum treatment. Serum FSH was significantly (P < 0·01) increased at 8 h after antiserum injection on either day 33 or on days −3/−2 to a level of 250 and 800% of control levels respectively. Thus, injection with inhibin–neutralizing antiserum into prepubertal female rats resulted, through an increase in serum FSH concentration 8 h after injection, in the growth of additional numbers of healthy antral follicles. Supranormal ovulation rate occurred if antiserum injections were given within the last 5 days before first ovulation, with a maximal ovulation rate after injection on days −3/−2. The data support the view that, in the immature female rat during the last 5 days before the day of first ovulation, inhibin is (through its regulation of serum FSH levels) progressively involved in the control of follicle growth and ovulation rate. Journal of Endocrinology (1991) 130, 289–296

BIOLOGICAL EFFECTS OF HUMAN URINARY FOLLICLE STIMULATING HORMONE

1970 ◽  
Vol 63 (3) ◽  
pp. 454-475 ◽  
Author(s):  
P. Petrusz ◽  
C. Robyn ◽  
E. Diczfalusy
Keyword(s):  
Biological Effects ◽  
Follicle Stimulating Hormone ◽  
Interstitial Cells ◽  
Female Rats ◽  
Male Rats ◽  
Weight Increase ◽  
Uterine Weight ◽  
Immature Female ◽  
Ovarian Weight ◽  
Female Mice

ABSTRACT The biological effects of human follicle stimulating hormone (FSH) preparations were studied in intact immature female mice and in hypophysectomized immature female and male rats, following the complete neutralization of the luteinizing hormone (LH) content of human urinary menopausal gonadotrophin (HMG) preparations having – prior to neutralization – FSH:LH ratios ranging between 1.0 and 500.0. Neutralization of LH was achieved by the addition of rabbit anti-human chorionic gonadotrophin (HCG) sera of known anti-LH potency. The amount of anti-LH employed was 1.5 to 730 times more than that required for 100% neutralization. In intact immature female mice, such »LH-free« FSH preparations induced an increased ovarian weight, follicle stimulation, as well as a uterine weight increase. In immature hypophysectomized female rats, »LH-free« FSH preparations induced ovarian weight increase, growth and maturation of the Graafian follicles without repair of the deficient interstitial cells and without any signs of luteinization. These ovarian changes were associated with an increase in uterine weight and with vaginal cornification. In view of these data, it is concluded that human urinary FSH per se is capable of inducing oestrogen synthesis in hypophysectomized female rats. In immature hypophysectomized male rats, »LH-free« FSH preparations induced testicular enlargement without any stimulation of the testicular interstitial cells and without any growth of the ventral prostate and seminal vesicles. The same effects were obtained following a prolonged administration (3 weeks); spermiogenesis was stimulated, but no mature spermatozoa were found.

Diurnal variation in uterine estrogen receptors in immature female rats - Inhibition by Arginine Vasotocin

1979 ◽  
Vol 6 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Mary K. Vaughan ◽  
James Buchanan ◽  
David E. Blask ◽  
Russel J. Reiter ◽  
Peter J. Sheridan
Keyword(s):  
Diurnal Variation ◽  
Estrogen Receptors ◽  
Arginine Vasotocin ◽  
Female Rats ◽  
Immature Female

FOLLICLE STIMULATING HORMONE-LIKE ACTIVITY IN HUMAN CHORIONIC GONADOTROPHIN PREPARATIONS

1969 ◽  
Vol 60 (1) ◽  
pp. 137-156 ◽  
Author(s):  
C. Robyn ◽  
P. Petrusz ◽  
E. Diczfalusy
Keyword(s):  
Follicle Stimulating Hormone ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Immature Female ◽  
Ovarian Weight ◽  
Wide Range ◽  
Immature Rats ◽  
Stimulation Of ◽  
Stimulating Hormone

ABSTRACT The follicle stimulating hormone (FSH)-like activity of human chorionic gonadotrophin (HCG) preparations was assayed by the method based on the ovarian weight augmentation in intact immature rats. The potencies ranged from 4.8 to 7.4 IU equivalents of FSH per mg. The FSH-like potency of the Second International Standard Preparation of HCG was 8.5 IU per vial. However, when in intact immature rats the ovarian weight response to HCG preparations was compared at a wide range of doses (40 to 51 200 IU) to that obtained with a human menopausal gonadotrophin (HMG) preparation (0.5 to 128 IU of FSH) in the presence of 40 IU of HCG, significant differences were found. The assays conducted in hypophysectomised immature female rats were invalid, because of lack of parallelism. Antisera were prepared by immunising rabbits with HCG and human hypophysial gonadotrophin (HHG) preparations and the antigonadotrophin profiles (HCG-, FSH- and FSH-like neutralising potencies) of these antisera were established by the use of statistically valid bioassay procedures. The anti-HCG and anti-HHG sera neutralised the FSH activity of HMG preparations as well as the FSH-like activity of HCG preparations. However, 3 to 175 times more antiserum was required to neutralise the equivalent of 1.0 IU of FSH-like activity present in HCG than expected on the basis of the anti-FSH potency of the antisera. On the other hand, there was a high degree of correlation between the neutralising potencies of the antisera when tested against the FSH-like activity and the HCG activity of various HCG preparations. When the FSH-like activity of an HCG preparation was quantitatively neutralised with an anti-HCG serum, some 30 per cent of the HCG activity remained unneutralised, as evidenced by repeated bioassays. Although at least 2000 IU of this »FSH-free« HCG was administered to groups of intact as well as hypophysectomised immature female rats, this high dose of HCG did not induce an increase in ovarian weight beyond that elicited by 40 IU of untreated HCG. Histological examination of the ovaries indicated lack of follicle stimulation in the hypophysectomised, but not in the intact immature animals. There was an excessive stimulation of the interstitial cells in both types of animals. The data indicate that the FSH-like activity of HCG preparations is neither due to a contamination by FSH of pituitary origin, nor is it an evenly distributed intrinsic property of the HCG molecules. It is also concluded that the gonadotrophic activity of biologically pure HCG in immature hypophysectomised female rats consists of a specific stimulation of the interstitial cell apparatus. Such HCG preparations do not induce any follicle stimulation, not even when administered in excessive doses.

Effect of Toki-Shakuyaku-San on Ovulation Induced by Human Menopausal Gonadotropin in Rats

1988 ◽  
Vol 16 (03n04) ◽  
pp. 169-172 ◽  
Author(s):  
Takao Koyama ◽  
N. Hagino ◽  
Anna W. Cothron ◽  
Motoi Saito
Keyword(s):  
Drinking Water ◽  
Female Rats ◽  
Human Menopausal Gonadotropin ◽  
Immature Female ◽  
Neuroendocrine Control ◽  
Induced Ovulation

One hundred and thirty-five immature female rats were treated with Toki-Shakuyaku-San (TSS : 500 mg/kg, Bwt in drinking water) beginning at 25 days of age and continuing during experimental sessions. Fifteen IU of the human menopausal gonadotropin (hMG:Gonadoryl: GNR:GNR 4 contains 4 to 1 ratio of FSH and LH) was injected intraperitoneally on the morning of 28 days of age, and ovulation (presence of tubal ova) was examined on the morning of 29, 30 and 31 days of age. GNR 4 alone induced ovulation at 29 days of age (70%) and at 30 days of age (35%); however, no ovulation was observed at 31 days of age. TSS treatment alone causes 30% to ovulate at 31 days of age. When GNR 4 was combined with TSS treatment, animals demonstrated ovulation at 31 days of age, that is, they ovulated at 29 days of age (93%), at 30 days of age (30percnt;) and at 31 days of age (90%). These results infer that TSS treatment may accelerate the chain of events in the neuroendocrine control on ovulation, thus causing more frequent ovulation in rats.

242 POTENTIAL ESTROGENIC EFFECT(S) OF PARABENS AT THE NEONATAL STAGE OF AN IMMATURE FEMALE RAT MODEL

2010 ◽  
Vol 22 (1) ◽  
pp. 279
Author(s):  
S. H. Hyun ◽  
E. B. Jeung
Keyword(s):  
Body Weight ◽  
Rat Model ◽  
Estrogenic Activity ◽  
Female Rats ◽  
Female Rat ◽  
Dependent Manner ◽  
Methyl Ethyl ◽  
Immature Female ◽  
Immature Rats ◽  
Dose Dependent

In this study, to examine the estrogenic activity effects of parabens on hormonal responsiveness and on change in the morphology of reproductive target tissues during a critical development stage in female rats, analyses for parabens including methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutylparaben were performed in an immature female Sprague-Dawley rat model. Two hundred female immature rats (n = 10/group) were orally treated with these parabens from postnatal day 21 to 40 in a dose-dependent manner based on our previous study [62.5, 250, and 1000 mg/kg of body weight (BW) per day]. 17α-ethinylestradiol (EE;1 mg/kg of BWper day) was used as a positive control and corn oil as a vehicle.A high doseofmethyl- and isopropylparaben (1000 mg/kg of BW per day) resulted in a significant delay in the date of vaginal opening and a decrease in length of the estrous cycle (P < 0.05). In measurements of organ weight and body weight, we observed significant weight changes in ovaries, adrenal glands, thyroid glands, liver, and kidneys(P < 0.05); conversely, body weight was not altered following paraben treatment. In all groups exposedto paraben treatment, histological analysis of the ovaries from the immature rats revealed interstitial cell disorders, a lack of corpora lutea, an increase in the number of cystic follicles, and thinning of the follicular epithelium, which occurred in a dose-dependent manner. In addition, morphological studies of the uterus revealed the myometrial dysplasia suchas myometrial hyperplasia inthe high-doseofpropyl- and isopropylparaben (1000 mg/kgof BWper day) group and in all dose of butyl- and isobutylparabens groups. We also observed a significant decrease in serum estradiol and T4 concentrations in methyl-, ethyl-, propyl-, isopropyl-, and isobutylparaben-treated groups (P < 0.01 and 0.05).A receptor-binding assay indicated that the relative binding affini- ties of parabens to estrogen receptors occurred in the order: isobutylparaben > butylparaben > isopropylparaben = propylparaben > ethylparaben. These values were much less than the binding affinity for 17?-estradiol. Taken together, long-term exposure to parabens, which show less estrogenic activity than EEl, can produce suppressive effects on hormonal responsiveness and can disrupt the morphology of reproductive target tissues during this critical stage of development in immature female rats.

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