LH- and chorionic gonadotrophin-stimulated progesterone release in vitro by intact luteal tissue of the marmoset monkey (Callithrix jacchus)

1994 ◽  
Vol 141 (3) ◽  
pp. 403-409 ◽  
Author(s):  
A Einspanier ◽  
J K Hodges

Abstract The application of an in vitro microdialysis system (MDS) for studies on the gonadotrophic control of luteal progesterone secretion in the marmoset monkey is described. Luteal tissue collected from a total of six animals (9 ± 1 days after ovulation) was perfused with Ringer solution (without and with lipoprotein, 0·6 μg/ml). The tissue was exposed to repeated applications of human LH (hLH) and human chorionic gonadotrophin (hCG) (1, 10 and 100 IU/ml) each of 60 min duration. Perfusate was collected in 15-min fractions and assayed for progesterone content. Results showed that addition of lipoproteins to the Ringer solution had a marked effect on progesterone secretion in terms of maintaining stable baseline levels and improving reproducibility of gonadotrophin-induced responses. Progesterone secretion was significantly stimulated by both gonadotrophins at each dose tested. Maximal elevations were obtained with 10 IU/ml and there were no apparent differences in responses to hLH and hCG in terms of either magnitude or duration. This study indicates that MDS provides a useful in vitro approach for studying the gonadotrophic control of the corpus luteum in non-human primates. The results did not demonstrate disparate actions of hLH and hCG in their ability to stimulate luteal progesterone secretion. Journal of Endocrinology (1994) 141, 403–409

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.


2012 ◽  
Vol 24 (3) ◽  
pp. 472 ◽  
Author(s):  
D. Rizos ◽  
S. Scully ◽  
A. K. Kelly ◽  
A. D. Ealy ◽  
R. Moros ◽  
...  

The aim of the present study was to test the hypothesis that elevated concentrations of progesterone (P4) resulting from the induction of an accessory corpus luteum (CL) by human chorionic gonadotrophin (hCG) administration on Day 5 after oestrus would lead to advanced conceptus elongation on Day 14 following embryo transfer on Day 7. The oestrous cycles of cross-bred beef heifers were synchronised and animals were randomly assigned to receive either of two treatments: (1) intramuscular injection of 3000 IU hCG on Day 5 after oestrus (n = 14); or (2) intramuscular injection of saline on Day 5 after oestrus (n = 13). Ovaries were scanned daily by transrectal ultrasonography to assess CL development. Serum concentrations of P4 were determined from daily blood samples collected from the jugular vein. In vitro-produced bovine blastocysts were transferred to synchronised recipients on Day 7 after oestrus (n = 15 blastocysts per recipient). Heifers were killed on Day 14 after oestrus and the uterus was flushed to recover the embryos. Injection of hCG on Day 5 induced ovulation of the dominant follicle in all treated heifers and increased the total area of luteal tissue on the ovary, which was associated with a significant increase (P < 0.001) in serum concentrations of P4 from Day 7 to Day 14. Positive associations were detected between circulating P4 with CL area (within-day correlations ranging from r = 0.45 to r = 0.67) and total area of luteal tissue (within-day correlations ranging from r = 0.65 to r = 0.86) Administration of hCG did not affect the proportion of Day 14 conceptuses recovered. However, compared with the control group, hCG-treated heifers had increased conceptus length (3.91 ± 1.23 vs 5.57 ± 1.02 mm, respectively; P = 0.06), width (1.00 ± 0.06 vs 1.45 ± 0.05 mm, respectively; P = 0.002) and area (5.71 ± 0.97 vs 8.31 ± 0.83, respectively; P = 0.02). Although numerically greater, mean interferon-τ (IFNT) production in vitro did not differ significantly (P = 0.54) between embryos recovered from hCG-treated and control heifers. In contrast, there was a strong positive correlation between individual embryo length (r = 0.76; P < 0.001) and individual embryo area (r = 0.72; P < 0.001) and IFNT production. In conclusion, administration of hCG on Day 5 after oestrus resulted in the formation of an accessory CL and hypertrophy of the original CL, the result of which was an increase in P4 concentrations from Day 7 onwards. These elevated P4 concentrations were associated with an increased conceptus area. Furthermore, conceptus size was highly correlated with IFNT secretion in vitro.


1984 ◽  
Vol 103 (1) ◽  
pp. 107-110 ◽  
Author(s):  
M. G. Hunter

ABSTRACT Human luteal tissue recovered from varying stages of the luteal phase was minced and incubated for 3 h and the effect of human chorionic gonadotrophin (hCG), prolactin and hCG + prolactin on progesterone and oestradiol production measured. While hCG generally enhanced both progesterone and oestradiol synthesis, prolactin alone at either 20 or 200 μg/l had no significant effect on steroidogenesis. When prolactin was added along with hCG in four of six corpora lutea, however, progesterone production significantly increased and in three of six corpora lutea oestradiol production was increased above that induced by hCG alone. It is concluded that prolactin may play some role in the control of steroidogenesis by the human corpus luteum. J. Endocr. (1984) 103, 107–110


1997 ◽  
Vol 154 (2) ◽  
pp. 259-265 ◽  
Author(s):  
R K Arioua ◽  
A Benhaïm ◽  
C Féral ◽  
P Leymarie

Abstract Previous studies on rabbit corpus luteum (CL) led to the conclusion that the luteotrophic complex, in rabbit, may include LH as well as oestradiol for normal luteal function. However, the requirement for LH is controversial. We have recently demonstrated the existence of a human chorionic gonadotrophin (hCG)-stimulated aromatase activity in cultured corpora lutea from a hyperstimulated pseudopregnant rabbit model, which develops a large number of corpora lutea, with only a few or no follicles in the ovaries. The present study was undertaken to investigate the in vitro responsiveness to hCG, dibutyryl cAMP (dbcAMP) and oestradiol of those corpora lutea. Pseudopregnancy (PP) was induced in rabbits by i.m. injection of 200 IU equine chorionic gonadotrophin daily for 2 days followed on day 4 by i.m. injection of 200 IU hCG (day 0 of PP). Luteal tissue and small and large luteal cells obtained at days 5 and 9 of PP were cultured for 24 h or during several days respectively with or without hCG, dbcAMP or oestradiol. Basal progesterone secretion was 3·6- and 22-fold higher in large cells compared with small ones at day 5 and 9 of PP respectively. When stimulated by small doses of hCG, luteal tissue responded by a 5-fold increase in progesterone secretion. Small cells produced four times higher amounts of progesterone than controls in the presence of 1 mIU/ml hCG and more than ten times in the presence of 0·1 IU/ml hCG, whereas large cells were insensitive to hCG stimulation. dbcAMP mimicked the effect of hCG on progesterone secretion by luteal tissue and luteal cells and oestradiol stimulated basal progesterone secretion in both small and large luteal cells. Given the large contribution of non stimulated large cells to luteal progesterone production and the remarkably high sensitivity of luteal tissue to gonadotrophin in vitro it seems that interactions between the two types of cells might occur during LH stimulation. Our results suggest that LH could participate in the luteotrophic complex at least in part through the stimulation of endogenous oestradiol production by luteal cells. Journal of Endocrinology (1997) 154, 259–265


1973 ◽  
Vol 57 (2) ◽  
pp. 299-305 ◽  
Author(s):  
D. T. BAIRD ◽  
R. A. COLLETT

SUMMARY The response of the ovine corpus luteum to repeated infusions of luteinizing hormone (LH) or of human chorionic gonadotrophin (HCG) was tested in four ewes with the left ovary autotransplanted to the neck. Constant infusion for 1 h of either LH (100 or 1000 μg/h) or HCG (200 i.u./h) via the ovarian artery stimulated a temporary increase in secretion of progesterone which fell to control levels by 60 min. Ovarian blood flow increased progressively (P < 0·05) throughout the infusion of gonadotrophin in three of the five experiments. A second infusion of either gonadotrophin after a further control hour failed to stimulate progesterone secretion. These results suggest that ovine luteal tissue rapidly becomes refractory to the steroidogenic effect of LH in vivo.


1985 ◽  
Vol 110 (4) ◽  
pp. 553-557 ◽  
Author(s):  
Julie A. Jonassen ◽  
Alan S. McNeilly

Abstract. To examine the effects of prolactin (Prl) and human chorionic gonadotrophin (hCG) on progesterone production by murine ovarian explants, immature female mice were injected with 4 IU pregnant mare's serum gonadotrophin (PMSG) to induce follicular maturation. After 24 or 40 h mice were killed, ovaries removed, cut into fragments and maintained as explants for 24 h in the presence or absence of ovine or human Prl (25–2500 ng/ml). None of these doses of Prl affected basal progesterone accumulation into media over 24 h. To determine if Prl could modify the capacity of ovarian explants to respond to gonadotrophin, ovaries were incubated with 25 IU/ml hCG for 3 h after an initial 24 h incubation period with or without Prl. Prl had no effect on basal progesterone accumulation but significantly enhanced hCG-stimulated progesterone accumulation during the 3 h incubation period. We conclude that Prl does not inhibit but may enhance progesterone secretion by pre-ovulatory follicles in the mouse.


1981 ◽  
Vol 91 (2) ◽  
pp. 197-203 ◽  
Author(s):  
M. C. RICHARDSON ◽  
G. M. MASSON

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared with two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared from mid- and late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (1 μmol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.


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