ADRENAL INVOLVEMENT IN THE TIMING OF PUBERTY IN FEMALE RATS: INTERACTION WITH SERUM PROLACTIN LEVELS

1978 ◽  
Vol 89 (3) ◽  
pp. 590-598 ◽  
Author(s):  
Marie C. Gelato ◽  
J. Meites ◽  
W. Wuttke
Keyword(s):  
Female Rats ◽  
Serum Prolactin ◽  
Vaginal Opening ◽  
Sprague Dawley ◽  
Intact Control ◽  
Immature Rats ◽  
Timing Of Puberty ◽  
Corticosterone Treatment ◽  
Adrenalectomized Rats ◽  
Intact Rats

ABSTRACT Female Sprague-Dawley derived rats were either sham-operated or adrenalectomized at 20 days of age. Treatment of separate groups of rats with progesterone, corticosterone or prolactin was started at 21 days of age, and was continued until the day of vaginal opening. Similarly treated rats were decapitated at 25, 29 and 33 days of age and at the day of vaginal opening and the sera were collected from each animal and assayed for prolactin, LH and FSH. All rats were decapitated between 4–6 p. m. Adrenalectomy, as previously reported, significantly delayed the day of vaginal opening. Prolactin treatment advanced the day of vaginal opening in intact rats and it restored the day of vaginal opening in adrenalectomized rats to that of intact control rats. Progesterone treatment always delayed the day of vaginal opening in intact rats. It caused an even greater delay in vaginal opening than adrenalectomy alone. Corticosterone treatment, on the other hand, was able to reverse the effect of adrenalectomy but had no effect on vaginal opening in intact rats. In intact rats serum prolactin levels rose steadily until the day of vaginal opening. Adrenalectomized and intact rats treated with progesterone had significantly decreased serum prolactin levels. However, in adrenalectomized corticosterone treated rats serum prolactin levels were significantly increased at all ages measured when compared to the untreated rats. The FSH and LH levels showed no significant changes during any of these experimental procedures. Approximately 50 % of the rats showed LH peaks on the day of vaginal opening as well as an increase in FSH. The data indicate a prolactin-adrenal interaction for the timing of the onset of puberty in immature rats, assuming that the day of vaginal opening in association with increased gonadotrophin levels is an indicator for the occurrence of puberty.

ADRENALECTOMY HAS A DIFFERENTIAL EFFECT ON THE OVARIAN RESPONSE OF TWO STRAINS OF RAT

1980 ◽  
Vol 87 (2) ◽  
pp. 241-246 ◽  
Author(s):  
J. J. JACOBS ◽  
R. D. PEPPLER
Keyword(s):  
Environmental Conditions ◽  
Regulatory Mechanism ◽  
Ovarian Response ◽  
Oestrous Cycle ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Corticosterone Treatment ◽  
Different Strains ◽  
Adrenalectomized Rats ◽  
Intact Rats

Evidence indicates that the ovarian regulatory mechanism of different strains of rat may respond differently to adrenalectomy; this study examined that possibility. Adult female Sprague–Dawley and Holtzman rats were maintained under constant environmental conditions and each strain was divided into groups: intact; adrenalectomized; unilaterally ovariectomized; adrenalectomized and unilaterally ovariectomized for 30 days; adrenalectomized 30 days previously and then unilaterally ovariectomized followed by one oestrous cycle; adrenalectomized 30 days previously and then unilaterally ovariectomized followed by one oestrous cycle with progesterone treatment (2 mg); adrenalectomized 30 days previously and then unilaterally ovariectomized followed by one oestrous cycle with corticosterone treatment (2·5 mg/100 g). All operations and autopsies were performed at metoestrus. Chronically adrenalectomized rats shed fewer ova per ovary than intact animals. Rats that had been unilaterally ovariectomized or adrenalectomized and unilaterally ovariectomized for 30 days showed compensatory ovulation as compared with intact rats and rats adrenalectomized for 30 days. Only the Sprague–Dawley rats that were adrenalectomized for 30 days and unilaterally ovariectomized for one oestrous cycle demonstrated compensatory ovulation. The remaining ovary in similarly treated Holtzman rats failed to compensate. Neither progesterone nor corticosterone influenced compensatory ovulation in the Sprague–Dawley rats, but both hormones caused an increase in the number of eggs ovulated in the Holtzman animals. In conclusion, the results of this study indicated that there is a strain-specific responsiveness of the ovary to adrenalectomy as assessed by compensatory ovulation.

POSITIVE FEEDBACK ACTION OF OESTRADIOL ON GONADOTROPHIN RELEASE IN 15 DAY OLD FEMALE RATS

1977 ◽  
Vol 86 (2) ◽  
pp. 263-272 ◽  
Author(s):  
J. Kronibus ◽  
W. Wuttke
Keyword(s):  
Column Chromatography ◽  
Positive Feedback ◽  
Female Rats ◽  
Intact Control ◽  
Partial Separation ◽  
Ovx Rats ◽  
Serum Lh ◽  
The Mean ◽  
Intact Rats

ABSTRACT Female rats were ovariectomized (ovx), adrenalectomized (adx) or both (adx-ovx) on day 8 after birth. The serum gonadotrophin concentrations on day 15 were higher in ovx and adx-ovx rats than in sham-operated or untreated controls of the same age. Intact animals on day 15 had higher LH and FSH levels compared with adult, dioestrous levels, and a number of LH peaks were observed. After partial separation of oestradiol (LH 20 column chromatography) from other lipid substances which interfere with the radioimmunoassay for oestradiol, levels of oestradiol were undetectable in ovx and in adx-ovx animals on day 15 but concentrations were relatively high in intact or adx rats. To test whether the high gonadotrophin concentrations in 15-day-old intact rats were due to a positive feedback action of oestradiol, silastic tubes containing different amounts of oestradiol were implanted on day 8 at the time of adrenalectomy and ovariectomy. The mean serum LH and FSH concentrations were increased on day 15 in those animals in which silastic tube implantation resulted in physiological oestradiol levels. These elevated gonadotrophin values were due to a number of peak levels. Injection of 600 μg progesterone on day 15, 8 h before decapitation resulted in high FSH levels in all the implanted animals, whereas LH levels were still variable from one animal to another. This situation is very similar to that in intact control rats and it is concluded that the hypothalamo-pituitary axis in 15-day-old female rats reacts to an oestrogenic stimulus followed by a progestational reaction as does the adult "gonadostat". This would account for the premature, pre-ovulatory type of LH peaks.

THE SENSITIVITY OF ADRENALECTOMIZED RATS TO GONADOTROPHINS

1954 ◽  
Vol 11 (4) ◽  
pp. 359-376 ◽  
Author(s):  
ANITA M. MANDL
Keyword(s):  
Chorionic Gonadotrophin ◽  
Female Rats ◽  
Corpora Lutea ◽  
Surgical Trauma ◽  
Normal Reaction ◽  
Normal Response ◽  
Immature Female ◽  
Adult Rats ◽  
Immature Rats ◽  
Adrenalectomized Rats

SUMMARY The sensitivity of adrenalectomized, control-operated and unoperated rats to pregnant mare serum (PMS) and chorionic gonadotrophin (CG) has been studied. A total of 638 mature and immature female rats was used. The ovaries of adrenalectomized rats were found to contain fewer large follicles and corpora lutea than those of control-operated litter-mates, and the slight ovarian hypertrophy which occurs after surgical trauma was found to be due to an increase in the number of Graafian follicles and corpora lutea. Further experiment showed that, as judged by the weight of the ovaries, adrenalectomy reduces the ovarian reaction to injected PMS (10 i.u./day) in both adult and immature rats. Replacement therapy with DCA (1 mg/day) failed to re-establish the normal response in adults. Treatment with cortisone (1 mg/day) restored the normal reaction in both adult and immature adrenalectomized rats. Adrenalectomized adult rats responded to injected CG (10 i.u./day) as vigorously as their operated and unoperated litter-mates. On the other hand, immature adrenalectomized animals did not respond fully to CG. Treatment with cortisone again fully restored the normal reaction.

EFFECTS OF ADRENALECTOMY ON THE RELEASE OF FOLLICLE-STIMULATING HORMONE AND THE ONSET OF PUBERTY IN FEMALE RATS

1977 ◽  
Vol 75 (3) ◽  
pp. 419-426 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER
Keyword(s):  
Body Weight ◽  
Adrenal Gland ◽  
Follicle Stimulating Hormone ◽  
The Body ◽  
Biologically Active ◽  
Female Rats ◽  
Vaginal Opening ◽  
Uterine Weight ◽  
Body Weights ◽  
Adrenalectomized Rats

The involvement of the adrenal gland in the release of gonadotrophins and the onset of puberty in female rats was studied. Two and four days after adrenalectomy (ADX) on either day 5 or 10 after birth, a significant decrease in the concentration of FSH was found; 4 days after ADX on either day 15 or 20, FSH concentrations had increased significantly compared with sham-operated and/or intact controls. However, in the rats adrenalectomized on day 15 or 20, the body weights were lower than in control rats. Relative uterine weights (mg/100 g body wt) in adrenalectomized rats never differed from those of control rats. A delay in the time at which vaginal opening and the first oestrus occurred was found in rats adrenalectomized at 20 or 25 days of age; however this delay was accompanied in these rats by a retardation in the gain in body weight. It is argued that the effects of ADX on both the release of gonadotrophins and the onset of puberty are primarily, and presumably exclusively, due to the effects on general bodily development (expressed in body weight). The lack of effect of ADX on uterine weight supports the hypothesis that 'oestrogen-like' products from the adrenal gland are not biologically active as oestrogens.

Effects of sex hormone levels on aortic vascular reactivity and variables associated with the metabolic syndrome in sucrose-fed female rats

2008 ◽  
Vol 86 (1-2) ◽  
pp. 25-35 ◽  
Author(s):  
Israel Pérez-Torres ◽  
Mohammed El Hafidi ◽  
Oscar Infante ◽  
Guadalupe Baños
Keyword(s):  
Metabolic Syndrome ◽  
Vascular Reactivity ◽  
Hormone Treatment ◽  
Female Rats ◽  
Serum Triglycerides ◽  
Intact Control ◽  
The Metabolic Syndrome ◽  
Sucrose Diet ◽  
Aortic Vascular Reactivity ◽  
Intact Rats

We studied the effect of varying levels of sex hormones, induced by ovariectomy and administration of testosterone or estradiol, on aortic reactivity in female rats with metabolic syndrome (MS) induced by a sucrose diet. Vasoreactivity of aortic rings, blood pressure, intra-abdominal fat, serum triglycerides, nitrates and nitrites, and TBARS were evaluated. Intact MS and ovariectomized MS had higher BP than intact control (C) and ovariectomized C, respectively; estradiol administration decreased BP in ovariectomized MS but not in ovariectomized C. Triglycerides and fat were both higher in MS. Triglycerides were not modified by surgery or hormone treatment, but ovariectomy increased fat. When ovariectomy was combined with hormones, however, fat was reduced to the level of intact rats. Ovariectomy decreased, but hormones increased, serum nitrates and nitrites. Vasoconstriction was larger in intact MS and ovariectomized MS + testosterone aortas than in intact C and ovariectomized C + testosterone, respectively. Vasodilation was reduced in intact MS and ovariectomized MS + testosterone compared with intact C, ovariectomized C + testosterone, ovariectomized MS, and ovariectomized MS + estradiol. The results suggest endothelial dysfunction in intact MS and ovariectomized MS + testosterone, but protection by ovariectomy + estradiol in MS due to hormones. Indomethacin reduced all contractions, but the effect was greater in estradiol-treated rats. l-NAME increased contractility, more in the ovariectomized C and MS groups and less in the estradiol-treated groups.

SERUM GONADOTROPHINS AND FOLLICULAR DEVELOPMENT IN IMMATURE RATS AFTER EARLY ANDROGEN ADMINISTRATION

1976 ◽  
Vol 68 (3) ◽  
pp. 461-468 ◽  
Author(s):  
J. TH. J. UILENBROEK ◽  
E. ARENDSEN DE WOLFF-EXALTO ◽  
M. A. BLANKENSTEIN
Keyword(s):  
Testosterone Propionate ◽  
Follicle Stimulating Hormone ◽  
Follicular Development ◽  
Female Rats ◽  
Vaginal Opening ◽  
Follicular Growth ◽  
Antral Follicles ◽  
Follicular Maturation ◽  
Immature Rats ◽  
Plasma Oestradiol

SUMMARY Follicular development and serum gonadotrophin levels were studied in female rats after neonatal androgen administration. After injection of 1250 μg testosterone propionate (TP) on day 5 after birth the composition of the follicular population was altered: at nearly all ages the number of pre-antral follicles (follicular volume 2–20 × 105 μm3) was lower than in oil-treated rats, in some cases the number of small antral follicles (21–249 × 105 μm3) was also lower. Furthermore levels of serum follicle-stimulating hormone and luteinizing hormone were decreased from day 7 to day 20 suggesting that the high gonadotrophin levels before day 20 are of importance for normal follicular development. In contrast, final follicular maturation in TP-treated rats was enhanced; at day 35 more large antral follicles (follicular volume ≥ 500 × 105μm3) were present in TP-treated rats than in oil-treated rats. The presence of more large antral follicles was accompanied by higher plasma oestradiol concentrations, higher uterine weights and advanced vaginal opening. These results demonstrate an inhibition of normal follicular growth and an acceleration of ovarian maturation after neonatal androgen administration.

Hypothalamic hyperinsulinemia and obesity: role of adrenal glucocorticoids

1983 ◽  
Vol 245 (2) ◽  
pp. E194-E199
Author(s):  
B. M. King ◽  
A. R. Banta ◽  
G. N. Tharel ◽  
B. K. Bruce ◽  
L. A. Frohman
Keyword(s):  
Insulin Secretion ◽  
Food Intake ◽  
Plasma Insulin ◽  
Female Rats ◽  
Hypothalamic Obesity ◽  
Previous Conclusion ◽  
Glucose Levels ◽  
Corticosterone Treatment ◽  
Adrenalectomized Rats

The effects of adrenalectomy on the obesity and hyperinsulinemia induced by ventromedial hypothalamic (VMH) lesions were studied in female rats. Plasma insulin and glucose levels were assayed after a 4-h fast and 17 min after the initiation of a meal (6 ml sweetened milk in 7 min). The development of hypothalamic obesity was prevented by prior adrenalectomy and restored by administration of corticosterone. Adrenalectomy abolished both the basal and postabsorptive hyperinsulinemia observed in sham-adrenalectomized rats with VMH lesions. Corticosterone treatment of adrenalectomized animals enhanced both basal and postabsorptive insulin levels, but adrenalectomized rats with VMH lesions were hyperinsulinemic compared with animals with sham lesions only under the postabsorptive condition. Postabsorptive glucose levels were unaffected by either the lesion or adrenal ablation. The results support our previous conclusion that postabsorptive hyperinsulinemia is of greater importance than is basal hyperinsulinemia in the pathogenesis of hypothalamic obesity. Although the results are consistent with a stimulatory role of corticosterone on food intake mediating the postabsorptive hyperinsulinemia, a primary effect on CNS loci involved with the regulation of insulin secretion is also possible.

scholarly journals Minor involvement of somatic growth in the onset of puberty of Hatano high- and low-avoidance rats

Reproduction ◽  
2004 ◽  
Vol 127 (3) ◽  
pp. 389-395 ◽  
Author(s):  
M Shirota ◽  
M Sato ◽  
K Kojima ◽  
R Ohta
Keyword(s):  
Somatic Growth ◽  
Poor Performance ◽  
Postnatal Growth ◽  
Additional Treatment ◽  
Vaginal Opening ◽  
Sprague Dawley ◽  
Timing Of Puberty ◽  
Learning Test ◽  
Equine Chorionic Gonadotropin ◽  
Different Characteristics

The present study was planned to examine the effects of somatic growth on the determination of timing of puberty using Hatano high- and low-avoidance rats (HAAs and LAAs); the rats were genetically selected from Sprague–Dawley (SD) rats for good or poor performance in a two-way active avoidance-learning test. Since these two lines were found to have different characteristics, such as body weight at birth, maternal care and timing of male puberty, the present study characterized female puberty in Hatano rats and then compared postnatal growth and timing of puberty between the two lines of rats when they were nursed by foster SD dams. When nursed under biological dams, HAAs became heavier, exhibited vaginal opening at a younger age and first ovulation was accompanied by more oocytes than LAAs. In all of the HAAs, but none of the LAAs, ovulation was induced by a single s.c. injection of 5 IU equine chorionic gonadotropin (eCG) on day 22 after birth. An additional treatment with 10 IU human CG revealed that, in the ovaries of LAAs, a small number of follicles had developed to an ovulable stage as a result of the treatment. The fostering improved somatic growth, and weights of LAAs were sustained at a heavier level than those of fostered HAAs. The fostering, however, did not eliminate the line difference in the timing of puberty of both sexes; it did accelerate the vaginal opening of LAAs but not the balanopreputial separation. Thus, there is a phenotypic difference in the timing of female puberty in Hatano rats exhibiting a different timing of ovarian development in response to gonadotropin. The present study indicates that postnatal somatic growth is not the predominant determinant in the onset of puberty in Hatano rats.

INDIRECT EVIDENCES OF PROLACTIN INVOLVEMENT IN PRECOCIOUS PUBERTY INDUCED BY HYPOTHALAMIC LESIONS IN FEMALE RATS

1977 ◽  
Vol 85 (1) ◽  
pp. 11-17 ◽  
Author(s):  
E. O. Alvarez ◽  
J. L. Hancke ◽  
J. P. Advis
Keyword(s):  
Precocious Puberty ◽  
Secretion Rate ◽  
Female Rats ◽  
Milk Secretion ◽  
Vaginal Opening ◽  
Prolactin Release ◽  
Hypothalamic Area ◽  
Intact Control ◽  
Hypothalamic Lesions ◽  
Depletion Period

ABSTRACT The effects of 2-bromo-α-ergocryptine (CB-154) administration in maturing female rats with precocious puberty induced by hypothalamic lesions, as well as the milk secretion rate in these animals after their first parturition were studied. Treatment with CB-154 inhibited precocious vaginal opening induced by hypothalamic lesions. After the treatment with the derivative was terminated, the ovulatory response was not different from that of intact control rats. After their first parturition lesioned rats accumulate milk at a faster rate, following an initial depletion period, than their non-operated controls. These results suggest than an alteration in prolactin release may be involved in determining the precocious puberty induced by lesions of the anterior hypothalamic area.

ANDROSTANEDIOL SULPHATES IN PERIPHERAL BLOOD OF IMMATURE RATS AND SOME OF THEIR BIOLOGICAL EFFECTS

1976 ◽  
Vol 71 (3) ◽  
pp. 299-304 ◽  
Author(s):  
RIVKA RAVID ◽  
BENJAMIN ECKSTEIN
Keyword(s):  
Body Weight ◽  
Peripheral Blood ◽  
Biological Effects ◽  
Female Rats ◽  
Vaginal Opening ◽  
Free Alcohol ◽  
Immature Female ◽  
Immature Rats ◽  
Medial Hypothalamus

SUMMARY The conjugation of 5α-androstane-3α,17β-diol (3α-A) and its 3β epimer (3β-A) was determined in the peripheral blood of immature female rats. About two thirds of these steroids were present in blood as sulphates and one third as glucuronides; no free steroids were detected. Administration of 3β-A sulphate (25 μg/100 g body weight/day) and of 3α-A sulphate (50 μg/100 g/day) from day 21 of life until the day of vaginal opening, advanced the day of the first ovulation. Administration of the 3β-A sulphate did not induce precocious vaginal opening whereas the free alcohol was active in this respect. Implantation of 3β-A sulphate, but not of the 3α epimer, into the basal medial hypothalamus resulted in the death of all animals within 24 h.

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