ASPECTS OF THE REGULATION OF CORPUS LUTEUM FUNCTION IN ANDROGEN-STERILIZED FEMALE RATS

1964 ◽  
Vol 46 (4) ◽  
pp. 571-579 ◽  
Author(s):  
G. H. Zeilmaker
Keyword(s):  
Pituitary Gland ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Female Rats ◽  
Male Rats ◽  
Corpora Lutea ◽  
Normal Female ◽  
Cervical Stimulation ◽  
Lh Secretion

ABSTRACT Some aspects of the regulation of function of artificially induced corpora lutea in androgen-sterilized female rats have been studied. The morphology of the vaginal epithelium and the distribution of sudanophilic materials in the luteal cells served as criteria for possible corpus luteum function. Pseudopregnancy, i. e. corpus luteum function during a defined period, as can be observed in female rats after sterile copulation, could not be induced in androgen-sterilized rats by daily cervical stimulation, by three daily injections of reserpine or by the presence of an isotransplanted pituitary gland during the first four days after the induction of corpus luteum formation. Prolonged corpus luteum function during at least 45 days was observed in animals bearing an isotransplanted pituitary gland under the kidney capsule. It is suggested that the evenly distributed sudanophilia in these corpora lutea is a result of the »tonic LH secretion« of the pituitary gland in situ. Comparison with similar studies in male rats led to the conclusion that an ovulation-inducing release of gonadotrophins plays a major role in the termination of the luteal phase in normal female rats. In ovariectomized androgen-sterilized rats treated with progesterone and oestrone a decreased response of the uterus to a traumatic stimulus was noticed as compared with the response in similarly treated normal rats.

EXPERIMENTAL STUDIES ON THE REGULATION OF CORPUS LUTEUM FUNCTION IN CASTRATED MALE RATS BEARING A TRANSPLANTED OVARY

1963 ◽  
Vol 43 (2) ◽  
pp. 246-254 ◽  
Author(s):  
G. H. Zeilmaker
Keyword(s):  
Pituitary Gland ◽  
Corpus Luteum ◽  
Functional Activity ◽  
Experimental Studies ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Corpora Lutea ◽  
Female Rat ◽  
Progesterone Production

ABSTRACT The functional activity of artificially induced corpora lutea in isologous ovaries transplanted into castrated male rats has been studied. Criteria for progesterone production were the morphology of vaginal transplants and the distribution of sudanophilic material in the corpus luteum cells. It was found that spontaneous functional activity of the corpora lutea did not occur in short-term experiments. Progesterone production was observed, however, in animals also bearing an isotransplanted (either male or female) pituitary gland, and in animals which received daily injections of reserpine. It is suggested that the normal influence of the central nervous system on the secretion of luteotrophic hormone is inhibitory in male as well as in female animals. Some aspects of the induction and maintenance of luteal function in castrated male rats bearing a transplanted ovary have been studied and compared with similar phenomena in the female rat. A real pseudopregnancy, i. e. maintained by the pituitary in situ during a defined period, as can be observed in female rats, could not be induced in these animals. In animals also bearing an isografted pituitary gland, luteolysis was not observed in experiments lasting up to 45 days. It is suggested that these findings may be correlated with the way in which the luteinizing hormone is secreted in the male rat.

Observations on the effects of prolactin on LH-receptors and steroidogenesis in corpus luteum and testis of the hypophysectomized rat

1982 ◽  
Vol 99 (3) ◽  
pp. 437-442 ◽  
Author(s):  
R. J. C. van Straalen ◽  
G. H. Zeilmaker
Keyword(s):  
Pituitary Gland ◽  
Corpus Luteum ◽  
Binding Sites ◽  
Female Rats ◽  
Male Rats ◽  
Rapid Decline ◽  
Corpora Lutea ◽  
Serum Progesterone ◽  
Male And Female Rats ◽  
Hypophysectomized Rats

Abstract. In this study the effects of hypophysectomy and autotransplantation of the pituitary gland on the concentration of hCG-binding sites (LH-receptors) and steroidogenesis in the corpus luteum and the testis of the rat were investigated. It was found that during pseudopregnancy both hCG-binding to homogenates of isolated corpora lutea and the progesterone levels in blood increase until day 7 and subsequently decrease until day 13. Hypophysectomy on day 5 led to a decrease of the number of LH-receptors and the serum progesterone level. By contrast hypophysectomy followed by autotransplantation of the pituitary gland increased the LH-receptor concentration and progesterone synthesis in spite of non-detectable LH-levels. Progesterone implants in hypophysectomized rats did not influence the number of LH-receptors. Hypophysectomy on day 0 without pituitary gland transplantation did not prevent the formation of some luteal LH-receptors measured on day 5 although progesterone was not secreted. A similar effect of prolactin secreted by pituitary autografts on LH-receptors was seen in the testis. The rapid decline of the number of binding sites normally observed after hypophysectomy was prevented by the presence of two pituitary autografts. Testosterone and LH-levels were non-detectable in the operated male rats. These data show that progesterone secretion by the corpora lutea is always associated with the presence of LH-receptors, regardless whether serum LH-levels are detectable or not. Moreover it appears that prolactin maintains or even increases the amount of LH-receptors in hypophysectomized male and female rats.

Steroid concentrations in rat corpora lutea isolated during the oestrous cycle and pseudopregnancy: effect of induction of ovulation at dioestrus

1989 ◽  
Vol 120 (2) ◽  
pp. 325-330 ◽  
Author(s):  
J. Th. J. Uilenbroek ◽  
P. J. A. Woutersen ◽  
P. D. M. van der Vaart
Keyword(s):  
Pituitary Gland ◽  
Corpus Luteum ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Serum Concentrations ◽  
Kidney Capsule ◽  
Cervical Stimulation ◽  
Sensitive Method

ABSTRACT Corpora lutea could be identified under the dissection microscope up to 7 days after formation. They were isolated during the oestrous cycle and pseudopregnancy and the progesterone and 20α-OH-progesterone contents were compared with serum values of these steroids. The pattern of progesterone in serum resembled that found in the corpora lutea. However, the pattern of 20α-OH-progesterone concentrations in serum and corpora lutea were different. While 20α-OH-progesterone concentrations in the corpora lutea showed large variations during the cycle, changes in serum concentrations of 20α-OH-progesterone were relatively small. Measurement of hormone concentrations in isolated corpora lutea is therefore a sensitive method for studying corpus luteum activity. To study whether corpora lutea derived after ovulation of immature follicles showed deficient luteal activity, rats at dioestrus (2 days before pro-oestrus) were induced to ovulate by the injection of 10 IU human chorionic gonadotrophin (hCG) and subsequent luteal activity was studied by measuring hormone concentrations in the corpora lutea on day 5 of pseudopregnancy. Concentrations of progesterone, but not of 20α-OH-progesterone, in corpora lutea derived from follicles induced to ovulate at dioestrusday 1 were significantly lower than those in corpora lutea derived from follicles induced to ovulate at prooestrus. This difference was observed not only when pseudopregnancy was induced by cervical stimulation but also when it was induced by implantation of a pituitary gland under the kidney capsule. However, in the latter case, corpora lutea already present on the day of hCG injection also became activated. The present experiments demonstrate that by measuring hormone concentrations in isolated corpora lutea changes in luteal activity can be studied effectively. Moreover, it appears that corpora lutea derived from immature follicles contained less progesterone than those derived from fully mature follicles. Journal of Endocrinology (1989) 120, 325–330

Indomethacin treatment prevents prolactin-induced luteolysis in the rat

1987 ◽  
Vol 112 (2) ◽  
pp. 317-322 ◽  
Author(s):  
J. E. Sánchez-Criado ◽  
K. Ochiai ◽  
I. Rothchild
Keyword(s):  
Corpus Luteum ◽  
Left Kidney ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Silicone Elastomer ◽  
Serum Prolactin ◽  
Corpora Lutea ◽  
Synthesis Inhibitor ◽  
Significant Difference ◽  
Indomethacin Treatment

ABSTRACT Adult female rats were hypophysectomized and their pituitary glands autotransplanted beneath the left kidney capsule on day 2 (day 1 was the day of ovulation). In such rats the pituitary secretes prolactin fairly constantly and the corpora lutea secrete progesterone for several months. To induce the luteolytic effect of prolactin the rats were first injected s.c. with 2-bromo-α-ergocryptine (CB-154) on cycle days 12, 13 and 14 (i.e. 10, 11 and 12 days after operation) to depress prolactin secretion, and then with CB-154 vehicle (70% ethanol) daily until cycle day 21, to allow prolactin secretion to resume. One ovary was removed from each rat on day 15 and the remaining one on day 22. The mean (± s.e.m.) weight of the corpora lutea on day 15 was 1·46±0·06 mg and 0·98±0·07 mg on day 22 (n = 17). In contrast, rats in which the CB-154 treatment was maintained to day 21 had corpora lutea which weighed 1·31 ±0·09 on day 15 and 1·47 ±0·08 mg on day 22 (n = 15). To investigate whether indomethacin, a prostaglandin synthesis inhibitor, affected the luteolytic action of prolactin, the experiment was repeated, but on day 15 (after the removal of one ovary) the groups in which CB-154 treatment was stopped, as well as the group in which CB-154 treatment was maintained, were each divided into two groups. In one, indomethacin-containing silicone elastomer wafers and, in the other, blank silicone elastomer wafers, were placed within the bursa of the remaining ovary. There were no differences in corpus luteum weight on day 15 among any of these groups and the two groups of the first experiment. There was no significant difference in corpus luteum weight between day 15 and day 22 in any of the six groups except for the two groups treated with the CB-154 vehicle and not with indomethacin. Thus, treatment with indomethacin prevented the fall in corpus luteum weight associated with the discontinuation of CB-154 treatment. Serum prolactin levels fell until day 15 in all rats and remained low in those in which the CB-154 treatment was maintained to day 21, but returned to control values in those treated with vehicle after day 14. Serum progesterone levels fell and remained low in all groups. Indomethacin treatment had no effect on the levels of either serum prolactin or progesterone. We conclude that some of the pharmacological effects of indomethacin are to prevent prolactin-induced luteolysis, and we suggest that prolactin induces rapid regression of the corpus luteum by stimulating intraluteal prostaglandin production or by being necessary for the effect of luteolytic prostaglandins. J. Endocr. (1987) 112, 317–322

Protective effects of estrogen on gender-specific development of diet-induced hypertension

2001 ◽  
Vol 91 (5) ◽  
pp. 2005-2009 ◽  
Author(s):  
Christian K. Roberts ◽  
Nosratola D. Vaziri ◽  
R. James Barnard
Keyword(s):  
Body Weight ◽  
Female Rats ◽  
Male Rats ◽  
Gonadal Hormone ◽  
Normal Female ◽  
Humoral Factors ◽  
Diet Modification ◽  
Ovx Rats ◽  
Hormone Status ◽  
Induced Hypertension

Dietary and humoral factors are thought to be involved in the development of hypertension. This study investigated the interaction between diet and gonadal hormone status in the development and reversibility of hypertension. Normal male and female and ovariectomized (OVX) female Fischer rats were placed on either a high-fat (primarily saturated), refined carbohydrate (sucrose) (HFS) or a low-fat, complex carbohydrate (LFCC) diet at 2 mo of age, and body weight and systolic blood pressure (BP) were measured. Male and OVX female rats were initially on the diets for 7 mo, whereas normal female rats were on the diets for 2 yr. After this initial phase, a group of rats from each of the normal HFS groups were converted to the LFCC diet for a period of 1 mo (males) and 2 mo (females). The OVX females were subcutaneously implanted with a 0.5-mg estradiol (E2) pellet for 1 mo. A significant rise in arterial BP occurred within 12 mo in female and only 2 mo in male rats on the HFS diet, exceeding 140 mmHg after 24 and 7 mo, respectively. Conversion from the HFS to the LFCC diet led to a normalization of BP in both female and male rats. HFS diet-induced hypertension was accelerated by OVX in female rats, approaching the pattern seen in male rats. The effect of OVX was completely reversed by E2replacement. BP did not significantly change in any of the LFCC groups at any time point, and E2 replacement had no effect on BP in the OVX LFCC group. All HFS groups had significantly greater body weight, with differences occurring sooner in the male and OVX rats compared with the female rats. Diet modification resulted in a partial but significant reduction of body weight, but E2replacement did not. These results demonstrate that long-term consumption of HFS diet induces hypertension in both genders and is reversible by diet modification. Hypertension is significantly delayed in females with functional ovaries. This protection is lost by OVX and restored by estrogen replacement. Thus hormone status contributes to the delayed onset of diet-induced hypertension in females compared with males.

scholarly journals Reproductive toxicity of triazole fungicides cyproconazole and epoxiconazole when exposed to male and female wistar rats during gametogenesis

2021 ◽  
Vol 54 (1) ◽  
pp. 52-61
Author(s):  
NR Shepelskaya ◽  
YaV Kolyanchuk
Keyword(s):  
Body Weight ◽  
Reproductive Toxicity ◽  
Reproductive Function ◽  
Female Rats ◽  
Male Rats ◽  
Corpora Lutea ◽  
Disruptive Effect ◽  
Male And Female ◽  
Two Samples ◽  
Adverse Effect Level

Aim. Studying the effect of generic pesticides cyproconazole (98 %) and two samples of epoxiconazole (epoxiconazole 1 — 95,75 % and epoxiconazole 2 — 98,7 %) on the reproductive system of male and female Wistar Han rats at the level of the organism when exposed during gametogenesis, identification and characterization of their hazard, as well as assessment of the risk of reproductive toxicity of these compounds. Materials and Methods. The test samples were administered daily (5 days a week) by oral gavage at doses of 0.2 and 2.0 mg/kg for cyproconazole and 0.5 and 2.0 mg/kg for epoxiconazoles during 11 weeks for males, and 10 weeks for females. Also, there were kept intact males and females, intended for crossover mating with experimental animals. After the end of the exposure, functional indicators of the state of the gonads and the ability of animals to reproduce offspring were studied. The duration and the frequency of each stage of the estrous cycle in female rats and the number of motile sperm, the total amount of sperm and the number of abnormal forms of germ cells of the male rats were studied. The reproductive function state in females was evaluated on day 20th of pregnancy. Thereby the number of corpora lutea in the ovaries, number of alive, dead and resorbed foetuses and embryos, the foetus weight, total weight of litters were registered. The studies were carried out in accordance with the recommendations of the Bioethics Commission and the Centre’s standard operating procedures, developed in accordance with the recommendations and requirements of Good Laboratory Practice (GLP). Conclusions. Test substances at a maximum dose of 2.0 mg/kg of body weight have reproductive toxicity and endocrine-disruptive effect, exerting a significant antiandrogenic effect on males and antiestrogenic effect on female rats. No-observed-adverse-effect-level (NOАEL) for gonadal and reproductive toxicity for male and female Wistar Han rats were established. They are 0.2 mg/kg body weight for cyproconazole and 0.5 mg/kg body weight for epoxiconazole. Key Words: azole fungicides, cyproconazole, epoxiconazole, reproductive toxicity, antiandrogenic and antiestrogenic effects, Wistar Han rats.

scholarly journals Immunohistological Localization and Expression of α-Actin in the Baboon (Papio anubis) Corpus Luteum

1997 ◽  
Vol 45 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Firyal S. Khan-Dawood ◽  
Jun Yang ◽  
M. Yusoff Dawood
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Adherens Junctions ◽  
Tunica Albuginea ◽  
Corpora Lutea ◽  
Papio Anubis ◽  
Lh Surge ◽  
Luteal Cells ◽  
Steroidogenic Cells ◽  
E Cadherin

We have recently shown the presence of E-cadherin and of α- and γ-catenins in human and baboon corpora lutea. These are components of adherens junctions between cells. The cytoplasmic catenins link the cell membrane-associated cadherins to the actin-based cytoskeleton. This interaction is necessary for the functional activity of the E-cad-herins. Our aim therefore was to determine the presence of α-actin in the baboon corpus luteum, to further establish whether the necessary components for E-cadherin activity are present in this tissue. An antibody specific for the smooth muscle isoform of actin, α-actin, was used for these studies. The results using immunohistochemistry show that (a) α-actin is present in steroidogenic cells of the active corpus luteum, theca externa of the corpus luteum, cells of the vasculature, and the tunica albuginea surrounding the ovary. The intensity of immunoreactivity for α-actin varied, with the cells of the vasculature reacting more intensely than the luteal cells. A difference in intensity of immunoreactivity was also observed among the luteal cells, with the inner granulosa cells showing stronger immunoreactivity than the peripheral theca lutein cells. There was no detectable immunoreactivity in the steroidogenic cells of the atretic corpus luteum. However, in both the active and atretic corpora lutea, α-actin-positive vascular cells were dispersed within the tissue. (b) Total α-actin (luteal and non-luteal), as determined by Western blot analyses, does not change during the luteal phase and subsequent corpus luteum demise (atretic corpora lutea). (c) hCG stimulated the expression of α-actin and progesterone secretion by the early luteal phase (LH surge + 1–5 days) and midluteal phase (LH surge + 6–10 days) cells in culture, but only progesterone in the late luteal phase (LH surge + 11–15 days). The data show that α-actin is present in luteal cells and that its expression is regulated by hCG, thus suggesting that E-cadherin may form functional adherens junctions in the corpus luteum.

A comparative study of the corpus luteum

1995 ◽  
Vol 7 (3) ◽  
pp. 303 ◽  
Author(s):  
RT Gemmell
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Hormonal Control ◽  
Egg Laying ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Embryonic Diapause ◽  
Alternative Reproductive Strategy ◽  
Uterine Development

The corpus luteum (CL) is a transitory organ which has a regulatory role in reproduction. Sharks, amphibians and reptiles have corpora lutea that produce progesterone which influences the rate of embryonic development. The egg-laying monotremes and the two major mammalian groups, eutherian and marsupial, have a CL that secretes progesterone. Most eutherians have allowed for the uterine development of their young by extending the length of the oestrous cycle and the CL or placenta actively secretes progesterone until birth. Gestation in the marsupial does not extend beyond the length of an oestrous cycle and the major part of fetal development takes place in the pouch. Where the extension of the post-luteal phase in the eutherian has allowed for the uterine development of young, the marsupial has extended the pre-luteal phase of the oestrous cycle and has evolved an alternative reproductive strategy, embryonic diapause. The mechanism for the secretion of hormones from the CL has been controversial for many years. Densely-staining secretory granules have been observed in the CL of sharks, marsupials and eutherians. These granules have been reported to contain relaxin, oxytocin or mesotocin, and progesterone. A hypothesis to suit all available data is that all hormones secreted by the CL are transported within such granules. In conclusion, although there are obvious differences in the mode of reproduction in the two main mammalian groups, it is apparent that there is a great deal of similarity in the hormonal control of regression of the CL and parturition.

Hepatic alpha 2 mu-globulin: a potential metabolic role in the rat proximal tubule

1996 ◽  
Vol 271 (3) ◽  
pp. F527-F538 ◽  
Author(s):  
S. C. Borkan ◽  
Y. H. Wang ◽  
K. T. Lam ◽  
P. Brecher ◽  
J. H. Schwartz
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Proximal Tubule ◽  
Glucose Oxidation ◽  
Renal Cortex ◽  
Female Rats ◽  
Male Rats ◽  
Normal Female ◽  
Fatty Acid Binding ◽  
Oxidation Rates

In the present study, we provide immunohistochemical and immunologic evidence to localize an abundant, 15.5-kDa protein to the soluble protein fraction of the proximal tubule. This 15.5-kDa protein binds fatty acids in vitro and has identity with amino acids 10-117 of alpha 2 mu-globulin (A2 fragment), a 19-kDa protein synthesized predominantly in the male liver. With reverse transcription-polymerase chain reaction, mRNA for A2 was detected in male liver but not in the male kidney. De novo accumulation of the 15.5-kDa protein was observed in the renal cortex of female rats given intravenous injections of purified 19-kDa protein (A2), suggesting intrarenal processing of the larger protein. The potential role of this protein in the proximal tubule, a site that utilizes fatty acids as an important metabolic substrate, was determined in isolated proximal tubule segments. Fatty acid and glucose oxidation rates were measured in three experimental models in which the 15.5-kDa protein was virtually absent: 1) uninephrectomized male rats treated with deoxycorticosterone acetate and salt, 2) male rats subjected to bilateral adrenalectomy, and 3) normal female rats. In the absence of the 15.5-kDa protein, fatty acid oxidation rates decreased by 30-55%, whereas glucose oxidation significantly increased in all three models. In female renal cortex, depletion of the 15.5-kDa protein was associated with a rise in heart fatty acid binding protein, an alternative intracellular transporter of fatty acids. These data support the hypothesis that a proteolytic cleavage product of hepatic alpha 2 mu-globulin may facilitate the oxidation of oleate, a hydrophobic ligand, in the proximal tubule.

Influence of in utero di-n-hexyl phthalate and di-cyclohexyl phthalate exposure on the endocrine glands and T3, T4, and TSH hormone levels of male and female rats: Postnatal outcomes

2020 ◽  
Vol 36 (6) ◽  
pp. 399-416
Author(s):  
Nurhayat Barlas ◽  
Emre Göktekin ◽  
Gözde Karabulut
Keyword(s):  
Pituitary Gland ◽  
Dose Group ◽  
Female Rats ◽  
Male Rats ◽  
High Dose ◽  
Hormone Levels ◽  
Male And Female Rats ◽  
Endocrine Organs ◽  
Body Weights ◽  
Juvenile Stages

The present study was designed to evaluate the effects of di- n-hexyl phthalate (DHP) and di-cyclohexyl phthalate (DCHP) on endocrine organs in rats. Oil control, 20-, 100-, and 500 mg/kg dose groups were selected and administered to pregnant rats on gestational days 6–19 by oral gavage. The neonatal stages of rats continued until postnatal day 20 and the- juvenile stages of rats continued until postnatal day of 32. The rats were allowed to mature until the neonatal and juvenile stages and there after, they were divided into four groups corresponding to the treatment levels. Body and organ weights were recorded, serum was collected, and thyroid, pancreas, pituitary gland, and adrenal gland were removed. There was a decrease in body weights in the 20- and 500mg/kg DHP and in the 20-mg/kg DCHP dose groups in neonatal male rats. In contrast, for female rats, there was an increase in body weights in the 100-mg/kg DCHP dose group and there was a decrease in body weights in the 500-mg/kg DHP dose group. Body weights were increased at 20 and 500 mg/kg in the DHP-exposed juvenile male rats. Serum thyroid-stimulating hormone (TSH) levels were increased in neonatal male rats, while they were increased in the 100-mg/kg DHP group of neonatal and juvenile female rats. Serum triiodothyronine (T3) levels were increased at the high dose of DHP for neonatal male rats and at the low and high dose levels of DCHP for female rats. Serum thyroxine (T4) levels were increased in neonatal rats for DHP. Also, some histopathological changes were observed in the thyroid, pancreas, adrenal, and pituitary gland. In conclusion, it was shown that DHP and DCHP caused negative effects on T3, T4, and TSH hormone levels.

Sign in / Sign up

Export Citation Format

Share Document