Internalization of receptor-bound human chorionic gonadotrophin in preovulatory rat granulosa cells in vivo

1983 ◽  
Vol 103 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Kalle Jääkeläinen ◽  
Seppo Markkanen ◽  
Hannu Rajaniemi

Abstract. The subcellular distribution of 125I-labelled human chorionic gonadotrophin (hCG) in preovulatory rat granulosa cells was studied in vivo. Pregnant mare serum gonadotrophin-pretreated immature female rats received an iv injection of [125I]hCG a few hours before the endogenous preovulatory gonadotrophin surge. The animals were killed at 2 or 6 h after the [125I]hCG injections. Light microscope autoradiographs showed that the mural granulosa cells of large follicles were the most highly labelled cells in the ovaries. Electron microscope autoradiography was used to study the subcellular distribution of radioactivity in the mural granulosa cells. At 2 h 45% of the counted silver grains were associated with the plasma membrane and 10% with the lysosomes, at 6 h the values were 51% and 9%, respectively. The distribution of the observed silver grains was compared with the generated expected source to grain pairs by computerized linear multiple regression analysis. The magnitudes of the regression coefficients revealed that the plasma membrane and the lysosomes were the only specifically 125I-labelled organelles, that a few radioactive molecules were located diffusely over the cytoplasm at 2 h and that the 125I-radioactivity of the nuclei was negligible. The present results suggest that preovulatory rat granulosa cells are in vivo able to internalize into lysosomes [125I]hCG initially bound to LH/hCG receptors of the plasma membrane.

1960 ◽  
Vol XXXIV (II) ◽  
pp. 176-188 ◽  
Author(s):  
A. Hasselblatt ◽  
Ch. Ratabongs

ABSTRACT The effect of pregnant mare serum gonadotrophin (PMS) and human chorionic gonadotrophin (HCG) on the thyroid gland of normal, of gonadectomized and of hypophysectomized infantile rats has been studied. Gonadotrophin treatment stimulated the thyroid of normal and hypophysectomized female rats. A corresponding effect was not observed in gonadectomized female or in normal and gonadectomized male rats. These results show that the gonadotrophic hormones stimulate thyroid function indirectly by increasing the hormonal secretion of the ovaries. An intimate functional relationship between the ovaries and the thyroid gland was thus demonstrated. As the stimulating effect of gonadotrophin treatment was also present in hypophysectomized female rats, it was concluded that the oestrogens act directly on the thyroid gland. Their thyrotrophic action is not mediated by the pituitary gland.


Reproduction ◽  
2005 ◽  
Vol 130 (1) ◽  
pp. 83-93 ◽  
Author(s):  
W Colin Duncan ◽  
Eva Gay ◽  
Jacqueline A Maybin

The human corpus luteum expresses genomic progesterone receptors (PRs) suggesting that progesterone may have an autocrine or paracrine role in luteal function. We hypothesised that the reduction in luteal PR reported in the late-luteal phase augmented progesterone withdrawal and had a role in luteolysis. We therefore tested the hypothesis that luteal rescue with human chorionic gonadotrophin (hCG) would maintain PR expression. PR was immunolocalised to different cell types in human corpora lutea (n = 35) from different stages of the luteal phase and after luteal rescue with exogenous hCG. There was no change in the staining intensity of theca-lutein cell or stromal cell PR throughout the luteal phase or after luteal rescue. In the late-luteal phase, granulosa-lutein cell PR immunostaining was reduced (P < 0.05) but the trend to reduction was also seen after luteal rescue with hCG (P = 0.055). To further investigate the effect of hCG on granulosa-lutein cell PR expression, an in vitro model system of cultured human luteinised granulosa cells was studied. Cells were cultured for 12–13 days exposed to different patterns of hCG and aminoglutethamide to manipulate progesterone secretion (P < 0.0001). Expression of PR A/B and PR B isoforms was examined by quantitative real-time RT-PCR. PR A/B mRNA was lower (P < 0.05) after 11–13 days of culture than after 7 days of culture. This reduction could not be prevented by hCG in the presence (P < 0.05) or absence (P < 0.05) of stimulated progesterone secretion. The expression of PR B mRNA showed a similar pattern (P = 0.054). Simulated early pregnancy in vivo and hCG treatment of luteinised granulosa cells in vitro did not appear to prevent the down-regulation of PR seen during luteolysis.


1970 ◽  
Vol 48 (3) ◽  
pp. 196-199 ◽  
Author(s):  
S. M. Husain ◽  
R. Saucier

Ovulation was induced in mature female rats by appropriately timed injections of pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG). Various combinations of the gonadotrophins were used. Maximal ovulatory response was consistently obtained with 50 I.U. PMSG and any combination of HCG between 50 I.U. and 5000 I.U. On the basis of the results obtained it is recommended that 50 I.U. PMSG and 50 I.U. HCG be injected to obtain a maximal ovulatory response in mature rats. High doses of PMSG (but not HCG) suppress ovulation markedly.


1964 ◽  
Vol 30 (2) ◽  
pp. 235-245 ◽  
Author(s):  
M. J. K. HARPER

SUMMARY The effects of chlormadinone (6-chloro-Δ6-17α-acetoxyprogesterone), an orally active progestational agent without significant oestrogenic activity, on the response of the ovaries of intact and hypophysectomized immature female rats to exogenous gonadotrophin have been examined. Administration of the steroid whether starting on the same day as, or 4 days before treatment with gonadotrophin, did not depress the ovarian response in intact rats. In hypophysectomized animals, pretreated with the progestagen, the ovarian response to gonadotrophin was depressed. In intact rats, treatment with the steroid and pregnant mare serum gonadotrophin (PMSG) resulted in ovulation, whereas in similar animals given PMSG alone no corpora lutea were found. Corpora lutea were seen in all groups given PMSG and human chorionic gonadotrophin (HCG) but ovulation occurred earlier when, in addition, treatment with the steroid was included. In only one experiment with intact rats did administration of the steroid alone cause a significant increase in uterine weight compared with controls. In neither experiment on hypophysectomized animals did such an increase occur, and significant decreases were recorded.


1994 ◽  
Vol 140 (3) ◽  
pp. 409-417 ◽  
Author(s):  
S A Ghersevich ◽  
M H Poutanen ◽  
H J Rajaniemi ◽  
R K Vihko

Abstract Antibodies against human placental 17β-hydroxysteroid dehydrogenase (17-HSD) and 17-HSD cDNA were used to study the expression of the corresponding enzyme in the immature rat ovary during follicular development and luteinization, which were induced by treating the animals with pregnant mare serum gonadotrophin (PMSG) or with PMSG followed by human chorionic gonadotrophin (hCG). Immuno-blot analysis indicated that the Mr of the 17-HSD expressed in rat granulosa cells was 35 000, as previously shown for the human placental enzyme. In immunohistochemical studies of untreated immature rat ovaries, only the granulosa cells from small antral follicles were stained. One day after PMSG treatment, strong expression of 17-HSD was observed in the granulosa cells of growing Graafian follicles. A marked decrease in enzyme expression was observed in preovulatory follicles on day 2 of PMSG treatment, starting from the basal layers of granulosa cells and progressing toward the luminal cells. No 17-HSD expression was detected in luteinized follicles or corpora lutea 22 h after hCG injection. The stroma and theca cells were negative for 17-HSD staining. In Northern hybridization analyses, two 17-HSD mRNAs were detected (1·4 and 1·7 kb). The strongest expression for both mRNAs was detected after 1 day of PMSG treatment, coinciding with maximal immunostaining of the enzyme protein. Down-regulation of 17-HSD observed by immunohistochemistry was reflected in a similar decrease in mRNA expression and the signals were almost undetectable 22 h after hCG injection. Our data suggest that 17-HSD expression in rat granulosa cells is up-regulated during follicular development and, thereafter, the enzyme expression is down-regulated during luteinization. Journal of Endocrinology (1994) 140, 409–417


1970 ◽  
Vol 46 (2) ◽  
pp. 221-227 ◽  
Author(s):  
B. M. BINDON

SUMMARY Antisera were raised to pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG) in male rabbits. The biological potencies of the antisera, A-PMSG and A-HCG, were determined against homologous antigens PMSG and HCG, using the mouse uterus test in immature mice. A single injection of A-PMSG was shown to inhibit the response to PMSG when injected as late as 21 days after the antiserum. The duration of inhibition was shown to depend on the dose of antiserum injected. These results were confirmed in hypophysectomized mice. A-HCG was shown to cause similar prolonged inhibition of the response to HCG in intact mice. The results suggest that A-PMSG and A-HCG persist in the circulation of the mouse for periods of time expected on the basis of the known half-life of rabbit γ-globulin (5 days).


1972 ◽  
Vol 55 (3) ◽  
pp. 533-541 ◽  
Author(s):  
J. Th. J. UILENBROEK ◽  
J. J. van der WERFF ten BOSCH

SUMMARY Ovulation-inducing effects of pregnant mare serum gonadotrophin (PMSG) were studied in immature female rats treated on day 5 (day 1 = day of birth) with oil or with 5 or 1250 μg testosterone propionate (TP). The response of rats treated with 1250 μg TP was negligible regardless of the age of the animals and of the dose of PMSG. The response of rats treated with 5 μg TP to PMSG alone was low (36% of rats, with 2·6 ova/ovulating rat), but could be improved by progesterone administration 2 days after PMSG injection (91% of rats, with 14·5 ova/ovulating rat). At every age and dose of PMSG tested the response of animals treated with 5 μg TP to combined PMSG and progesterone treatment was less than that of control animals. It is concluded that neonatal TP treatment diminishes the release of endogenous ovulating hormone subsequent to PMSG injection. This effect is dependent on the dose of TP used, but already demonstrable in animals treated with 5 μg TP on day 5, which would have been cyclic and fertile after puberty. Only for the animals treated with 1250 μg TP could a decreased sensitivity of the ovaries to combined administration of PMSG and human chorionic gonadotrophin be demonstrated.


1996 ◽  
Vol 8 (6) ◽  
pp. 961 ◽  
Author(s):  
EL Gregoraszczuk ◽  
M Skalka

To characterize thyroid hormone action in the ovary, the direct effect of triiodothyronine (T3) was investigated in vitro using a culture system of porcine theca cells (Tcs) and granulosa cells (Gcs) in mono- and co-culture (GT), the latter resembling follicles in vivo. The cells were cultured in the absence or presence of human chorionic gonadotrophin (hCG) with or without T3 (10(-7), 10(-9) or 10(-11) M). Follicular cells were obtained from follicles of different size (small, medium and large), and steroid secretion into the culture medium was detected by radioimmunoassay. T3 alone did not influence steroid secretion by Tcs and Gcs isolated from follicles that were small and medium in size. In preovulatory follicles, an increase in basal androgen secretion and a simultaneous decrease in oestradiol secretion were observed with Tcs and Gcs in both mono- and co-culture. T3 together with hCG decreased hCG-stimulated androgen secretion in Tcs isolated from medium-sized follicles and had a simultaneous stimulatory effect on hCG-stimulated oestradiol secretion by Gcs. In cultures of follicular cells obtained from large follicles, T3 decreased hCG-stimulated secretion of both androgen and oestrogen by Tcs and simultaneously stimulated oestradiol secretion in GT co-cultures. Thus, the interaction of T3 with gonadotrophin hormone modulated follicular steroidogenesis, depending on follicle size and cell type used in culture. The observed T3-induced increase in basal androgen secretion by Tcs could account for the atresia of follicles, since it is accompanied by a decrease in oestradiol secretion in GT co-culture. In its co-activity with hCG, an adequate level of T3 prevents excessive androgen production by Tcs, probably influencing aromatization processes in the follicle. An increase in hCG-stimulated oestradiol secretion in GT co-cultures is then observed. Further investigations are required to clarify whether this is linked with an effect on the aromatization processes occurring in the follicle.


1965 ◽  
Vol 33 (3) ◽  
pp. 447-454
Author(s):  
M. J. K. HARPER

SUMMARY Administration of chlormadinone, an orally active progestational agent without significant oestrogenic activity, to intact immature female rats did not affect either ovarian or uterine weight significantly compared with controls. A single injection of human chorionic gonadotrophin (HCG) caused a 73 % increase in uterine weight in 24 hr. over the control value. This dose significantly increased ovarian weight and although it caused some stimulation of follicular development, ovulation during this time did not occur. When animals were treated with chlormadinone for 8 days, and received HCG on the 8th day, uterine weight was 170% greater than in the controls and 56% greater than with HCG alone. The uterine weight produced was similar to that found in animals treated with mestranol, a potent oestrogen, and HCG. In ovariectomized animals HCG did not affect uterine weight, while the small increase produced by chlormadinone was unaltered when HCG also was given. Mechanisms are discussed by which this augmentation of the uterine response to HCG might be produced. It seems most likely that chlormadinone administration causes storage of endogenous gonadotrophin in the pituitary, and that the exogenous gonadotrophin acts as the 'trigger' for the release of stored hormone, probably by a direct action on the hypothalamus.


1978 ◽  
Vol 89 (1) ◽  
pp. 166-172 ◽  
Author(s):  
T. J. Weiss ◽  
D. T. Armstrong ◽  
J. E. A. McIntosh ◽  
R. F. Seamark

ABSTRACT Theca and granulosa tissues isolated from sheep ovarian follicles of different sizes were incubated in the presence of human chorionic gonadotrophin (HCG; 5 IU/ml) or follicle stimulating hormone (FSH; 5 μg NIH-FSH-S11/ml) for 40 min. Changes in the total amounts of cyclic 3′,5′-adenosine monophosphate (cAMP) were used as an index of the responsiveness of these preparations to the hormones. Thecal tissue of both large (4–6 mm in diameter) and small (1–3 mm) follicles responded similarly to gonadotrophins. Granulosa cells from small follicles failed to respond to stimulation by HCG. FSH, however, consistently increased cAMP production in comparison with controls or cells treated with HCG. Granulosa cells of large follicles responded to both HCG and FSH.


Sign in / Sign up

Export Citation Format

Share Document