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At least 19 recordsLinked to original sources
PubMed1976

Responses of plasma "estradiol" and plasma LH to ovariectomy, ovariectomy plus adrenalectomy, and estrogen injection at various ages.

Plasma LH and "estradiol" were measured by radioimmunoassay in female rats 5, 10, 15, 20, 25, 30, 40, and 80 days of age, and the changes in these hormone levels 24 h after ovariectomy, ovariectomy plus adrenalectomy, and estrogen injection were determined. Plasma "estradiol" was high at 5 days of age; it increased further to a peak at 15 days of age, and declined thereafter to the low levels seen in adult rats. At each age, plasma "estradiol" declined about 50% 24 h after ovariectomy, whereas it fell to undetectable levels 24 h after ovariectomy plus adrenalectomy at 20 and 80 days of age. Plasma LH did not increase 24 h following ovariectomy at 5 days of age, but it did at all ages thereafter. The peak increase occurred 24 h after ovariectomy at 15 days of age, and the increment was progressively smaller at older ages. Ovariectomy plus adrenalectomy did not cause a significantly greater increase in plasma LH than ovariectomy alone. Injection of estradiol caused a decrease in plasms LH at all ages except in the animals ovariectomized at 5 days of age. The greatest decrease was seen in animals ovariectomized at 15 days of age, with a progressively smaller negative feedback response as age increased. In addition to providing systematic data on changes in the negative feedback effect of estradiol at various ages, the results indicate that, especially in immature animals, there is a circulating substance which cross-reacts with antibodies to estradiol but which does not appear to be a biologically-active estrogen. It does not come from the ovaries and disappears from the circulation if the adrenals as well as the ovaries are removed.

Adrenal Glands↗
PubMed1977

Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive rat mammary carcinoma.

Growth of the transplantable mammary tumor, MTW9, in W/Fu rats is greatly enhanced by elevated serum prolactin concentrations. This report compares the prolactin binding to tumor membranes in two mammary tumor strains derived from MTW9. Maximum binding to membranes of both tumors occurred at pH 7.6 after incubation for 30 hr at 4 degrees. The binding was inhibited only by polypeptide hormones that possess lactogenic activity. MTW9-P, an ovariectomy-responsive tumor developed in rats maintained on daily perphenazine injections, had 4-fold-higher prolactin binding than had MTW9MtT, an ovariectomy-nonresponsive tumor developed in rats bearing the mammosomatotropic pituitary tumor, MtTW10. Withdrawal of perphenazine from rats bearing MTW9-P caused a fall to normal of plasma prolactin, no tumor regression, and no significant change in prolactin binding. In contrast, resection of MtT resulted in tumor regression, a fall to normal of serum prolactin, and a nearly 3-fold increase in prolactin binding. Scatchard plots of prolactin binding data yield an apparent affinity constant, Ka, of 1.2 X 109 liters/mole for both tumors. The 4-fold-higher prolactin binding in the ovariectomy responsive variant suggests a positive correlation between ovariectomy response and the number of membrane prolactin-binding sites. No correlation between prolactin sensitivity and prolacting binding is apparent.

Animals↗
PubMed1975

Acute effects of ovariectomy and sham ovariectomy on pituitary-ovarian phenomena in the mouse.

Four- and 5-day cyclic mice housed with and without males, respectively, were autopsied at 10 a.m. on proestrus (P) or estrus (E) after no treatment, or after ovariectomy (Ovax) or sham Ovax at 10 a.m. or 4 p.m. on one of the preceding 3 days. Results indicate the ovarian must be in situ between 4 p.m. the day before P and 10 a.m. the day of P for a normal proestrous uterine weight increase to occur in both 4- and 5-day cyclic mice. For estrous cornification to occur, ovaries must be in situ between 10 a.m. and 4 p.m. on diestrus (D) in 4-day cyclic mice, and between 4 p.m. on D-I and 10 a.m. on D-II in 5-day cyclic mice. Sham Ovax tended to inhibit ovulation in both 4- and 5-day cyclic mice. The effects of both Ovax and sham Ovax on proestrous and estrous pituitary LH values were variable. ttiming of the feedback relationship between ovary and hypothalamus-pituitary in mice may be imprecise, leading to easy disruption of the estrous cycle in this species.

Animals↗
PubMed1979

The effects on the rat uterus and placenta of ovariectomy at day 10 of pregnancy.

A study was made of the changes in morphology and in nuclear incorporation of tritiated thymidine in the rat uterus and placenta after ovariectomy at day 10 of gestation. There was some individual variation between different animals in the results of the ovariectomy, but in general the effects on both maternal and fetal tissues were more severe than those reported to follow ovariectomy at later stages of pregnancy. Even in the animals where there was extensive placental survival 2 or 3 days after the ovariectomy, normal differentiation of the placental labyrinth did not occur and the fetuses failed to survive. Ovariectomy had a pronounced effect on the proliferative activity of uterine epithelial cells. The high labelling index in the control animals up to day 12 was markedly reduced in the ovariectomized animals; after day 13, however, the labelling index of the controls was reduced to a level lower than that of the ovariectomized animals. Nuclear labelling occurred in the glandular epithelium from two days after ovariectomy, but was never present in the controls. There was a marked reduction in the percentage of labelled nuclei in the uterine muscle and in the metrial gland after ovariectomy. In the metrial gland this was associated with a reduction in the number of typical granulated cells and with the appearance of numerous small round cells. It is suggested that the latter represented metrial gland cell precursors which had undergone impairment of their normal differentiation process.

Animals↗
PubMed1975

Augmentation of pituitary responsiveness to luteinizing hormone/follicle stimulating hormone-releasing factor (LH-RF) as a result of acute ovariectomy in the four-day cyclic rat.

Within 6 h of ovariectomy in adult rats with 4-day estrous cycles, plasma FSH titers were significantly elevated above those of sham-operated controls at all stages of the estrous cycle, whereas plasma LH concentrations were raised by ovariectomy only during diestrus day 2, proestrus or estrus. A single intravenous injection of a partially purified extract of ovine stalk-median eminence tissue (LH-RF) into sham-operated control rats or incubation of pituitaries from similar rats with the same releasing factor extract elevated LH and FSH output at all stages of the cycle. This response to LH-RF was related to the stage of the estrous cycle, maximal pituitary responsiveness occurring on proestrus. Ovariectomy 6 h before administration of LH-RF significantly augmented pituitary LH and FSH responsiveness both in vivo and in vitro. This elevation in hypophyseal responsiveness observed in vitro followed a cyclic pattern which could be superimposed on the normal cyclic changes in pituitary responsiveness, whereas the cyclic increase in pituitary LH responsiveness to LH-RF in vivo following acute ovariectomy was first detectable 16 to 18 h earlier than in intact controls, that is, on late diestrus day 2 rather than on the morning of proestrus. These results indicate that acute ovariectomy can augment pituitary responsiveness to LH-RF and can also advance the onset of the cyclic augmentation of pituitary responsiveness to LH-RF during the 24 h immediately preceding the ovulatory gonadotropin surge. Possible explanations for these effects are discussed.

Animals↗
PubMed1975

Effects of antibody to oestrogen or of ovariectomy on the incorporation of [35-S]methionine into brain protein and on gonadotrophin levels during the oestrous cycle in the rat.

The incorporation of [35S]methionine into protein of the anterior pituitary and discrete brain areas was measured following the administration of antibodies to oestrogen, ovariectomy, or adrenalectomy on the afternoon of dioestrus. The antibody to oestrogen deleted the circadian rhythms of methionine incorporation normally observed in the various brain areas together with the peaks of incorporation normally observed in the median eminence area and anterior pituitary on the evening of pro-oestrus. The peaks of incorporative activity normally observed in the preoptic area and amygdala (relative to the putamen) at 03.00 h on the day of pro-oestrus were also deleted. Administration of the antiserum on the morning of pro-oestrus failed to alter the pattern of methionine incorporation normally observed on the evening of pro-oestrus. Ovariectomy performed at 16.00 h of dioestrus blocked the preovulatory rise of luteinizing hormone (LH) (as did the antibody to oestrogen) and inhibited the peak of methionine incorporation normally observed in the anterior pituitary on the evening of pro-oestrus. However, for the peak in the median eminence to be inhibited, ovariectomy had to be performed on the morning of the preceeding oestrus. Adrenalectomy alone, or adrenalectomy with ovariectomy, performed on the afternoon of dioestrus did not affect the levels of methionine incorporation in the brain or anterior pituitary at 18.00 h on the day of pro-oestrus. Animals which had been ovariectomized and injected with 2-5 mug oestradiol benzoate on the morning of oestrus showed significantly increased levels of methionine incorporation in all the brain areas and the anterior pituitary at 18.00 h of expected pro-oestrus. The administration of antibody to oestrogen to a similar group of animals on the afternoon of expected dioestrus inhibited the rise at 18.00 h of expected pro-oestrus. The apparent discrepancy between the results obtained with ovariectomy and the antiserum appeared to be due to the ability of the antiserum to neutralize the activity of oestrogens retained by the tissues. The present results suggest that the changes in incorporation of methionine into protein in the brain and anterior pituitary are brought about by the action of endogenous oestrogen: there appears to be a steady summative effect on the median eminence throughout the oestrous cycle together with a short-lived effect occurri4g during pro-oestrus and affecting the anterior pituitary.

Adrenalectomy↗
PubMed1976

Ovariectomy alone or in combination with dexamethasone in patients with advanced breast cancer and high levels of testosterone excretion.

The urinary testosterone levels of 40 premenopausal and postmenopausal patients with advanced breast carcinoma were assayed before and after ovariectomies. Histologic examination of the ovaries of 25 patients whose hormone levels were above normal revealed interstitial cell hyperplasia. Two months after the operations, the amounts of testosterone excreted by the womaen decreased significantly. We considered this as indirect evidence that the ovaries contributed to androgen synthesis. However, 15 patients had normal hormone excretion values that did not change 2 months postoperatively. Testosterone levels for 6 of the women 5 months after surgery were higher than at the previous testing. We surmised that the increased gonadotropic activity that followed ovariectomy migh have stimulated adrenal androgen secretion. To elucidate this point, we gave injections of 15,000 IU human chorionic gonadotropin (HCG) to breast cancer patients who were free of any recurrence and, 3 or 24 months previously, had undergone prophylactic ovariectomies (5 and 4 patients, respectively). In 5 of these women, the amount of testosterone excreted increased significantly after HGG was administered. We inhibited adrenal androgen secretion in 11 patients, whose presurgical urinary testosterone levels were above normal. After their ovaries were removed, these women received 1.5 mg dexamethaxone (DXM) daily for 30 days at a time, after which the amount of testosterone excreted was evaluated and, if the level was above 5.0 mug/24 hours, therapy was repeated for another 30 days. Of the patients who showed objective remission after ovarietomies, there were 4 (26.3%) of 15 who had normal androgen excretion levels; 8 (57.1%) of 14 had increased amounts and were treated by surgery alone; and 10 (90.9%) of 11 received a combination of ovariectomies and DXM therapy. The duration of regression was the highest in the latter group.

Adult↗
PubMed1975

Response of the pituitary of the catfish, Heteropneustes fossilis (Bloch), to bilateral ovariectomy.

Hypophyseal response to bilateral ovariectomy was studied in the catfish, Heteropneustes fossilis, during the prespawning (May) and the spawning (July) periods. During the prespawning period, a significant increase in the number of granulated PAS-positive basophils in the proximal pars distalis of the castrates was recorded on day 45 post-ovariectomy; thereafter a gradual degranulation of basophils was observed. However, in the spawning period a dramatic increase in the number of granulated basophils of the castrates was seen on day 8 post-ovariectomy and the number decreased thereafter. This differential response of the hypophysis to ovariectomy is discussed.

Animals↗
PubMed1978

Induction of mammary prolactin receptors and lactose synthesis after ovariectomy in the pregnant mouse.

The development of prolactin receptors in the mammary gland after ovariectomy was investigated in pregnant KA mice. Mice were ovariectomized on day 13 of pregnancy and used for the determination of the amount of specific binding of 125I-labelled prolactin to the mammary tissue, and the contents of lactose and nucleic acids in the mammary gland 0, 8, 24, and 72 hr after the operation. The specific binding of 125I-labelled prolactin, lactose and RNA contents in the mammary gland remained low until 8 hr, sharply increased 24 hr and decreased 72 hr after ovariectomy. When ovariectomized mice were treated with 0.2 mg progesterone, pregnancy was maintained and an increase (1.5-fold) in the amount of specific binding was observed with an increase of lactose content. Five mg progesterone completely inhibited lactose synthesis. Cortisol administered with progesterone did not show any specific change at the dose used (0.5 to 10 mg). Although the amount of specific binding was also increased after hysterectomy, this increase (2-fold) did not fully cover the increase after ovariectomy (3-fold). These results suggest that the recepter site for prolactin is induced before the initiation of lactose synthesis caused by ovariectomy during pregnancy.

Animals↗
PubMed1975

Reproduction in the ferret. I. The effect of ovariectomy on the course of gestation.

The role of the ovaries in the maintenance of pregnancy was studied in the ferret. Ovariectomy at the time of implantation showed that some embryos survived for 7 days after the operation but all were destroyed after 10 days, although the trophoblast continued to grow at a much faster rate than normal. Ovariectomy performed after implantation showed that no fetal development occurred when the ovaries were removed at Day 21 post coitum, but that fetuses developed for an appreciable length of time in animals ovariectomized on Days 23 to 27 post coitum. Ovariectomy in late gestation resulted in speedy expulsion of the fetuses. An increase in the placenta:fetus ratio did not alter the response to ovariectomy in late gestation. The uteri in all ovariectomized animals showed progestational endometria when examined shortly after explusion of the fetuses.

Animals↗
PubMed1979

Short- and long-term effects of hypophysectomy and unilateral ovariectomy on ovarian follicular populations in sheep.

The effects of hypophysectomy and unilateral ovariectomy on the total number of follicles with greater than 3 layers of granulosa cells were determined at 4 and 70 days following treatment. The population of preantral follicles (less than 0.23 min diam.) was found to be under the control of gonadotrophins but such control was only evident on a long-term basis. At 70 days after unilateral ovariectomy there was a large increase in the number of preantral follicles but at 70 days after hypophysectomy there was a large decrease. The population of antral follicles (greater than 0.23 mm diam.) was under the immediate control of gonadotrophins. By 4 days after hypophysectomy all large antral follicles had become atretic and the number of antral follicles was further decreased at 70 days after treatment. At 70 days after unilateral ovariectomy there was an increase in the number of antral follicles. The follicular growth rates at 70 days following treatment were decreased in hypophysectomized ewes but increased in ewes after unilateral ovariectomy.

Animals↗
PubMed1975

The effects of late ovariectomy on the proliferation and differentiation of the uterus of the pregnant rat.

The effects of ovariectomy at day 12 of pregnancy on the proliferative activity of the uterine epithelium, metrial gland and uterine muscle in the rat were studied by autoradiography in animals killed one hour after a single injection of tritiated thymidine. The results were amplified by histological and histochemical studies. One day after operation epithelial proliferation was impaired in the ovarectomized animals. From 16 days onwards, however, proliferative activity was at a lower level in controls than in the ovariectomized animals. Three days after ovariectomy uptake of tritiated thymidine by metrial gland cells was less than in the controls. The metrial gland became smaller after ovariectomy and showed histological and histochemical changes from the normal pattern. The increased thickness of the uterine muscle in the ovariectomized animals from the 16 day stage onwards was not associated with any significant change in the labelling index of the muscle cells. The results are discussed in relation to the changes in endocrine environment which may occur after ovariectomy.

Animals↗
PubMed1978

Inverse relation between estrogen receptors and cyclic adenosine 3':5'-monophosphate-binding proteins in hormone-dependent mammary tumor regression due to dibutyryl cyclic adenosine 3':5'-monophosphate treatment or ovariectomy.

During the growth arrest of 7,12-dimethylbenz(alpha) anthracene-induced rat mammary carcinomas following ovariectomy or N6, O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) treatment, a change in the specific estrogen and cAMP binding to tumor proteins is observed. Three days after ovariectomy or DBcAMP treatment of the hosts, cAMP binding increases 5- and 2-fold in the nuclei and cytosol of tumors, respectively, whereas nuclear and cytoplasmic estrogen binding decreases by 70 and 25%, respectively. These changes in cAMP- and estrogen-binding activities are detectable within 1 day after ovariectomy or DBcAMP treatment, and the changes are reversed when resumption of tumor growth is induced by the injection of estradiol valerate or cessation of DBcAMP treatment. When 7,12-dimethylbenz(alpha)anthracene-induced tumors fail to regress after ovariectomy or DBcAMP treatment, the change in estrogen and cAMP binding does not occur. Concomitant with the increase of cAMP-binding activity in regressing tumors are increases in histone kinase activity and the cAMP content of the tumors. These increases in cAMP-binding and protein kinase activities are blocked by cycloheximide. These data suggest an interaction between a steroid hormone and cAMP in the growth control of a hormone-dependent mammary tumor.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1979

Effects of neonatal ovariectomy upon 3H-estradiol uptake by target tissues of androgen-sterilized female rats.

Tissue distributions of radioactivity were studied at 2, 4 and 6 h after intravenous injection of 3H-estradiol-17 beta (48.6 ng/100 g b.w.) in 4 groups of 10 or 11 adult female rats with the following neonatal treatments: Control = sham ovariectomy (ovx) on day 1, oil injection on day 5 (n = 10); ovx = ovx on day 1, oil on day 5 (n = 11); TP = sham ovx on day 1, 30 micrograms testosterone propionate (TP) on day 5 (n = 10); ovx-TP = ovx on day 1, 30 micrograms TP on day 5 (n = 11). Neonatal TP treatment significantly hastened vaginal opening in all animals. After ovariectomy, vaginal opening occurred in 20/22 rats regardless of hormonal treatment; ovariectomy did not significantly affect the time of vaginal opening in these 20 animals. All ovariectomized animals had diestrous vaginal smears after puberty, all controls cycled normally and all of the TP group used for the uptake part were in persistent vaginal estrus (sequence of vaginal smears with 70% or more containing no leukocytes) confirmed by ovarian histology to be anovulatory (11/13 injected). 72 h prior to radioisotope injection, intact females in the above groups were ovariectomized and the neonatally ovariectomized were sham operated. Tissue radioactivity was extracted from the anterior, middle and posterior hypothalamus, hippocampus, amygdala, cerebrum, anterior pituitary, uterus and plasma. Neonatal ovariectomy raised 3H-estradiol concentrations in all tissues, except hippocampus and anterior pituitary, suggesting an increase in nonspecifically bound hormone. Neonatal TP decreased 3H-estradiol concentrations in the anterior and middle hypothalamus and uterus only, in both the intact and ovariectomized group, demonstrating a selective effect of neonatal TP upon subsequent development of estrogen binding capacities of target tissues that is independent of the ovaries.

Animals↗
PubMedDate not supplied

Plasma oxytocic activity after ovariectomy and stilboestrol or progesterone implantation in female rats.

Plasma oxytocic activity after ovariectomy and stillboestrol or progesterone implantation in female rats. Acta Physiol. Pol. 1977, 28 (2): 135--142. The purpose of this work was to compare the oxytocic activity of plasma in the intact rats, after ovariectomy, and in ovariectomized rats after subcutaneous implantation of stilboestrol or progesterone tablets. On the 22nd day after ovariectomy and implantation of hormones 2 ml of blood were obtained under urethane anaesthesia from the cephalad portion of the right external jugular vein. Plasma oxytocic activity was determined by the method of Van Dongen and Hays in Fragments of the rat mammary tissue at the time of lactation. The plasma oxytocic activity of ovariectomized female rats did not differ significantly from that found in the rats with implanted hormones. Cytological analysis of vaginal smears demonstrated stimulation of vaginal epithelium by exogenous hormones which lasted up to 10 days after implantation. Ovariectomy caused a threefold rise in the plasma oxytocic activity as compared with the control values.

Animals↗
PubMed1979

Changes in the metrial gland of the rat uterus following ovariectomy on day 10 of pregnancy.

Rats were subjected to ovariectomy or a control operation on day 10 of pregnancy and light and electron microscope studies carried out to examine the cells of the decidua basalis and the mesometrial triangle. Degeneration of the decidua basalis was rapid but proliferation in the mesometrial triangle and differentiation of the typical granulated cells continued for some time, and resulted in the formation of a metrial gland. The earliest effect noted in the metrial gland was the appearance of inclusions in the fibroblast-like stromal cells one day after ovariectomy. During the next four days many stromal cells became packed with a variety of inclusions and it is suggested that some of these may represent phagocytosed cellular debris. Some debris appeared to be in intercellular spaces and was probably derived from granulated cells. Some granulated cells appeared to develop apparently empty vacuoles and this may be a preliminary stage in degeneration. Although granulated cells decreased to become very few in number five days after ovariectomy, the precise mechanism of their loss and the relationship of this to the hormonal environment could not be established.

Animals↗
PubMed1977

Increase in dopamine content of the rat median eminence after long-term ovariectomy and its reversal by estrogen replacement.

The norepinephrine (NE) and dopamine (DA) concentrations of the median eminence and the remaining hypothalamus of female rats were assayed using a sensitive radioenzymatic method. There were no changes in the catecholamine concentrations of either brain region when measured in the mornings of the different days of the estrous cycle. Four to 5 weeks after ovariectomy there was a marked increase in the DA but not the NE content of the median eminence, and the daily administration of estradiol benzoate for 7 days prior to sacrifice reversed the ovariectomy-induced increase in DA. Ovariectomy did not alter catecholamine concentrations in the remaining hypothalamus.

Animals↗