Luteotrophic factors in hyperstimulated pseudopregnant rabbit: II – High sensitivity to hCG of luteal tissue and small luteal cells

1997 ◽  
Vol 154 (2) ◽  
pp. 259-265 ◽  
Author(s):  
R K Arioua ◽  
A Benhaïm ◽  
C Féral ◽  
P Leymarie
Keyword(s):  
High Sensitivity ◽  
Chorionic Gonadotrophin ◽  
Small Cells ◽  
Corpora Lutea ◽  
Aromatase Activity ◽  
Large Contribution ◽  
Luteal Cells ◽  
Progesterone Secretion ◽  
Luteal Tissue

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

Luteotrophic factors in hyperstimulated pseudopregnant rabbit: I – Evidence for aromatase activity in luteal tissue and luteal cells

1997 ◽  
Vol 154 (2) ◽  
pp. 249-257 ◽  
Author(s):  
R K Arioua ◽  
C Féral ◽  
A Benhaïm ◽  
B Delarue ◽  
P Leymarie
Keyword(s):  
Rabbit Model ◽  
Enzymatic Digestion ◽  
Small Cells ◽  
Luteal Cell ◽  
Corpora Lutea ◽  
Aromatase Activity ◽  
Luteal Cells ◽  
Luteal Tissue ◽  
Percoll Density Gradient

Abstract It is well established that the rabbit corpus luteum (CL) function depends upon endogenous oestradiol, the major source of which in the rabbit ovary is considered to be the ovarian follicles. The absence of oestradiol formation by the rabbit CL has been previously reported. In a hyperstimulated pseudopregnant rabbit model used in our laboratory which developed a large number of corpora lutea in response to chorionic gonadotrophin (eCG)/hCG, we observed the survival of corpora lutea in vivo, and normal levels of plasma progesterone throughout pseudopregnancy (PP), despite the scarcity or the absence of follicles as a source of the luteotrophic hormone. Measurement of oestradiol in the plasma indicated that it was at high levels and correlated with the number of corpora lutea. This led us to investigate the luteal origin of oestradiol in this model. PP was induced in rabbits by i.m. injection of 200 IU eCG daily for 2 days followed on day 4 by i.m. injection of 200 IU hCG (day 0 of PP). Luteal tissue obtained at days 5, 9 and 12 of PP and cultured for 24 h synthesized oestradiol and testosterone in addition to progesterone. However, under the same conditions, follicles had limited capacity to secrete oestradiol. The presence of an aromatase activity in luteal tissue was confirmed when exogenous testosterone was added to the culture medium. P450aromatase (P450arom) mRNA was found in luteal tissue at days 5, 9 and 12 of PP. Small or large luteal cells, obtained by enzymatic digestion of the tissue followed by centrifugation in a Percoll density gradient, were cultured during several days with or without gonadotrophin or dibutyryl cAMP (dbcAMP). Both types of cells secreted oestradiol. In small cells and luteal tissue, aromatase activity was stimulated (1·5–2-fold) by hCG and dbcAMP. Large cells exhibited a greater capacity to aromatize testosterone than small cells, but aromatase activity was not modified by hCG or by dbcAMP. FSH had no effect on aromatase activity of either luteal cell type. This intrinsic luteal tissue aromatase capacity and the absence of premature regression of corpora lutea despite the limited support of follicular oestrogen, suggest an autocrine and luteotrophic role for this luteal oestrogen. Journal of Endocrinology (1997) 154, 249–257

Contrasting effects of prolactin on luteal and follicular steroidogenesis

1985 ◽  
Vol 104 (2) ◽  
pp. 241-250 ◽  
Author(s):  
B. Kalison ◽  
M. L. Warshaw ◽  
G. Gibori
Keyword(s):  
Luteal Cell ◽  
Corpora Lutea ◽  
Aromatase Activity ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Progesterone Secretion ◽  
Hypophysectomized Rats ◽  
Stimulation Of

ABSTRACT To determine whether prolactin affects both luteal and follicular production of testosterone and oestradiol, pseudopregnant rats, either intact or hypophysectomized on day 8, were injected daily between days 8 and 9 with 1·5 i.u. human chorionic gonadotrophin (hCG), 250 μg prolactin or a combination of both. Control rats were given vehicle. On day 9, blood was obtained from the ovarian vein and corpora lutea and follicles were isolated and incubated in vitro for 2 h. Administration of hCG to intact rats increased ovarian secretion of testosterone and oestradiol dramatically, but did not affect progesterone secretion. Hypophysectomy on day 8 of pseudopregnancy was followed by a drop in ovarian steroid secretion. Prolactin treatment of hypophysectomized rats markedly enhanced progesterone production but had no stimulatory effect on either testosterone or oestradiol. In contrast, hCG dramatically enhanced ovarian secretion of both testosterone and oestradiol without affecting progesterone secretion. Prolactin administered together with hCG antagonized the stimulation of both testosterone and oestradiol secretion by hCG, yet increased progesterone production. When the specific effects of hCG and prolactin administration on follicles and corpora lutea were studied separately, it was found that hCG treatment in vivo greatly stimulated testosterone and oestradiol production by both tissues in vitro. Since hCG only marginally affected aromatase activity in the follicle, had no effect on aromatase activity in luteal cells and did not increase progesterone synthesis, it appears that hCG acts to increase the formation of androgen substrate for oestradiol biosynthesis. Prolactin, administered with or without hCG, inhibited both basal and hCG-stimulated testosterone and oestradiol synthesis by the follicle. In sharp contrast to its inhibitory effect on follicular production of steroids, prolactin appears to be essential for LH stimulation of testosterone and oestradiol by the corpus luteum. In the absence of prolactin, luteal cells gradually ceased to respond to LH and decreased their output of testosterone and oestradiol. Prolactin administration to hypophysectomized rats did not affect luteal cell production of either steroid. However, corpora lutea of rats treated with prolactin responded to the hCG challenge with an increase in testosterone and oestradiol synthesis. In summary, results of this investigation demonstrate that prolactin affects follicular and luteal production of testosterone and oestradiol in opposite ways. It acts on the follicle to inhibit both basal and LH-stimulated production of testosterone and oestradiol, yet it markedly enhances LH stimulation of testosterone and oestradiol synthesis by luteal cells. J. Endocr. (1985) 104, 241–250

scholarly journals Corpora lutea induced by gonadotrophin-releasing hormone treatment of anoestrous Welsh Mountain ewes: reduced sensitivity to luteinizing hormone in vivo and to chorionic gonadotrophin in vitro

Reproduction ◽  
2005 ◽  
Vol 129 (1) ◽  
pp. 61-73 ◽  
Author(s):  
T A Bramley ◽  
D Stirling ◽  
G S Menzies ◽  
D T Baird
Keyword(s):  
Chorionic Gonadotrophin ◽  
Luteal Cell ◽  
Corpora Lutea ◽  
Lh Receptor ◽  
Group 4 ◽  
Progesterone Secretion ◽  
Group 3 ◽  
Gonadotrophin Releasing Hormone

Seasonally anoestrous Welsh Mountain ewes received 250 ng gonadotrophin-releasing hormone (GnRH) every 2 h, with (Group 1;n= 13) or without (Group 2;n= 14) progesterone priming for 48 h. Fourteen control ewes (Group 3) were studied during the luteal phase in the breeding season. Animals in Group 4 (n= 12) received progesterone priming followed by 250 ng GnRH at increasing frequency for 72 h, while ewes in Group 5 (n= 13) were given three bolus injections of 30 μg GnRH at 90-min intervals. All treatment regimens induced ovulation. However, only corpora lutea (CL) from ewes in Group 3 (breeding season) or Group 4 exhibited normal luteal function. Luteal luteinizing hormone (LH) receptor levels were significantly higher on day 12 than day 4, and CL from groups with adequate CL (3 and 4) had significantly higher125I-human chorionic gonadotrophin (hCG)-binding levels than the three groups with inadequate CL on day 12. LH-binding affinity was unchanged. Exogenous ovine LH (10 μg)in vivoon days 3 or 11 after ovulation induced a pulse of progesterone in ewes with adequate CL: however, ewes in Groups 1, 2 and 5 showed no significant response. Basal progesterone secretionin vitrowas significantly greater on day 4 than on day 12. Maximal steroidogenic responses of adequate and inadequate CL to hCG and to dibutyryl cyclic-3′,5′-AMP were similar at both stages of the luteal phase. However, the EC50for hCG on days 4 and 12 was 10-fold lower for groups with an adequate CL (0.1 IU hCG/ml) than for inadequate-CL groups (1 IU hCG/ml;P<0.05). Thus, in addition to the well-characterized premature sensitivity of GnRH-induced inadequate CL to endometrial luteolysin, we have shown (1) a marked decrease in total number of cells in the CL, a profound reduction in vascular surface area, and a decrease in mean large luteal cell volume (with no change in large luteal cell numbers), (2) decreased luteal LH receptor and progesterone content compared with adequate CL and (3) that CL that were becoming, or were destined to become, inadequate failed to respond to ovine LHin vivoand were 10-fold less sensitive to hCG in terms of luteal progesterone secretionin vitro.

Effects of prolactin on steroid production by human luteal cells in vitro

1983 ◽  
Vol 96 (3) ◽  
pp. 499-503 ◽  
Author(s):  
G. J. S. Tan ◽  
J. S. G. Biggs
Keyword(s):  
Menstrual Cycle ◽  
Ovarian Function ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Short Term ◽  
Steroid Production ◽  
Luteal Cells ◽  
Progesterone Production

The effects of prolactin on steroidogenesis were studied in dispersed luteal cells prepared from human corpora lutea of the menstrual cycle. Prolactin, at concentrations of 0·1–1000 ng/ml, had no effect on progesterone production by luteal cells during short-term incubation (3 h). However, in two out of five corpora lutea, higher concentrations of prolactin (100 and 1000 ng/ml) significantly reduced the oestradiol-17β production induced by human chorionic gonadotrophin (hCG; 10 i.u./ml); lower doses of prolactin had little effect. In the remaining corpora lutea, prolactin failed to affect either basal or hCG-induced production of oestradiol-17β. These results are discussed in relation to the mechanism by which prolactin influences human ovarian function.

scholarly journals Assessment of the mechanism by which prolactin stimulates progesterone production by early corpora lutea of pigs

1998 ◽  
Vol 159 (2) ◽  
pp. 201-209 ◽  
Author(s):  
RE Ciereszko ◽  
BK Petroff ◽  
AC Ottobre ◽  
Z Guan ◽  
BT Stokes ◽  
...  
Keyword(s):  
Inositol Phosphate ◽  
Specific Binding ◽  
Positive Control ◽  
Free Calcium ◽  
Corpora Lutea ◽  
Pkc Inhibitor ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Progesterone Secretion

Previously, we reported that administration of prolactin (PRL) during the early luteal phase in sows increases plasma progesterone concentrations. In the current study, we searched for the mechanisms by which PRL exerts this luteotrophic effect. The objectives of the study were (1) to examine the effect of PRL and/or low-density lipoproteins (LDL) on progesterone production by porcine luteal cells derived from early corpora lutea, and (2) to assess the ability of PRL to activate phosphoinositide-specific phospholipase C (PI-PLC) and protein kinase C (PKC) in these luteal cells. Ovaries with early corpora lutea (day 1-2 of the oestrous cycle) were obtained from the slaughterhouse. Progesterone production by dispersed luteal cells was measured after treatment with PRL, phorbol 12-myristate 13-acetate or inhibitors of PKC in the presence or absence of LDL. LDL increased progesterone concentration in the incubation medium (304.5 vs 178.6 ng/ml in control, P<0.05). PRL augmented LDL-stimulated progesterone secretion by luteal cells (to 416 ng/ml, P<0.05), but PRL alone did not affect progesterone production (209.6 ng/ml, P>0.05). Staurosporine, a PKC inhibitor, inhibited progesterone secretion stimulated by the combined action of LDL and PRL; however, such inhibition was not demonstrated when cells were treated with the PKC inhibitor, H-7. PKC activation was assessed by measuring the specific association of [H]phorbol dibutyrate (H-PDBu) with luteal cells after treatment with PRL or ionomycin (a positive control). PRL and ionomycin increased H-PDBu-specific binding in early luteal cells by 28+/-5.5% (within 5 min) and 70.2+/-19.3% (within 2 min) over control binding respectively (P<0.05). In addition, PRL did not augment the LDL-stimulated progesterone production in PKC-deficient cells. In contrast with PKC, total inositol phosphate accumulation, as well as intracellular free calcium concentrations, were not affected by PRL in the current study. We conclude that PRL, in the presence of LDL, stimulates progesterone production by early corpora lutea in vitro. Moreover, PRL appears to activate PKC, but not PI-PLC, in these cells. Thus intracellular transduction of the PRL signal may involve activation of PKC that is not dependent on PI-PLC.

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
Keyword(s):  
Marked Effect ◽  
Ringer Solution ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Marmoset Monkey ◽  
Progesterone Secretion ◽  
Luteal Tissue ◽  
Repeated Applications ◽  
Baseline Levels

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

Control of inhibin production by dispersed human luteal cells in vitro

1992 ◽  
Vol 4 (1) ◽  
pp. 67 ◽  
Author(s):  
HZ Wang ◽  
SH Lu ◽  
XJ Han ◽  
ZD Sun ◽  
WX Shen ◽  
...  
Keyword(s):  
Sex Steroids ◽  
Follicle Stimulating Hormone ◽  
Calf Serum ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Luteal Cells ◽  
Oestradiol Production ◽  
Human Corpus Luteum

The production of inhibin in vitro by dispersed cells from early to mid (Days 16-19) and late stage (Day 23) human corpus luteum (CL) was examined, and the effects of human chorionic gonadotrophin (hCG), follicle stimulating hormone (FSH), oestradiol and testosterone on inhibin production were determined. Corpora lutea from five subjects in the early to mid luteal stage and three subjects in late luteal stage were dispersed with enzymes and the luteal cells cultured in medium supplemented with 5% calf serum and either FSH (1, 10 or 100 ng mL-1), oestradiol-17 beta (2.5, 5 or 10 micrograms mL-1) or testosterone (0.25, 1 or 5 micrograms mL-1) with or without hCG (1 I.U. mL-1). Cells were cultured for 1 to 3 days without changes of medium, and the concentrations of progesterone, oestradiol and immunoreactive inhibin in the medium were measured by radioimmunoassay. Cells from both types of CL produced inhibin in vitro under basal conditions, but only cells from early to mid CLs responded to hCG with a significant increase in inhibin production. Both progesterone and oestradiol production were stimulated by hCG in both groups of CL. Inhibin concentrations in the cell cultures declined with time in culture, particularly in the late CL group, whereas the concentration of steroids increased. Neither FSH, oestradiol nor testosterone significantly changed inhibin production in either CL group. It was concluded that inhibin production by human luteal cells in vitro is influenced by the age of the CL, and is dependent on LH (hCG) but not on FSH or sex steroids.

Prolactin stimulates steroidogenesis by human luteal tissue in vitro

1984 ◽  
Vol 103 (1) ◽  
pp. 107-110 ◽  
Author(s):  
M. G. Hunter
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Progesterone Production ◽  
Luteal Tissue ◽  
Oestradiol Production ◽  
Human Corpus Luteum

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

Effects of oestradiol and prolactin on progesterone production by rhesus monkey luteal cells in vitro

1985 ◽  
Vol 108 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Richard F. Laherty ◽  
Daniel Rotten ◽  
May Yamamoto ◽  
Robert B. Jaffe
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Corpora Lutea ◽  
Experimental Conditions ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Mechanical Disruption ◽  
Progesterone Secretion

Abstract. The effects of oestradiol and prolactin (Prl) on progesterone production by dispersed monkey luteal cells were examined. Corpora lutea were recovered from monkeys 5–7 days following ovulation induction during the puerperium. The tissue was dispersed by collagenase and mechanical disruption. The resulting cells were incubated in Dulbecco's modified Eagle's medium, containing the hormones to be tested, for 3 h at 37°C. The medium was removed and assayed for progesterone by RIA. Human luteinizing hormone (hLH) produced a significant, dose-related increase in progesterone secretion that was comparable to that produced by dibutyryl cyclic adenosine monophosphate. Human follicle stimulating hormone (hFSH) had no effect upon progesterone production by the luteal cells. Oestradiol (100–10 000 pg/ml) produced a significant, dose-related decrease in both basal and hLH-stimulated progesterone production. Ovine Prl (oPrl) had neither a stimulatory nor an inhibitory effect upon basal progesterone secretion at doses up to 1000 ng/ml. Further, oPrl did not affect hLH-stimulated progesterone production. We conclude that oestradiol is a potent inhibitor of luteal progesterone secretion in vitro and that Prl does not inhibit progesterone production in the primate corpus luteum under these experimental conditions.

Local production of progesterone by the corpus luteum of the marmoset monkey in response to perfusion with chorionic gonadotrophin and melatonin in vivo

1987 ◽  
Vol 112 (3) ◽  
pp. 449-457 ◽  
Author(s):  
G. E. Webley ◽  
J. P. Hearn
Keyword(s):  
Corpus Luteum ◽  
Positive Control ◽  
Chorionic Gonadotrophin ◽  
Test Material ◽  
Corpora Lutea ◽  
Local Production ◽  
Progesterone Secretion ◽  
Stimulation Of

ABSTRACT The effect of human chorionic gonadotrophin (hCG) and melatonin on the local production of progesterone by the marmoset corpus luteum was investigated in vivo using a perfusion cannula system. Progesterone secretion was measured in 10-min fractions of buffer which had been perfused through the corpus luteum at a flow rate of 70 μl/min for a maximum of 3 h in anaesthetized animals. Two corpora lutea were cannulated in each animal; one for perfusion of test material and the other for perfusion with buffer alone as a control. Perfusion with hCG (25 i.u./ml), investigated as a positive control, produced a marked stimulation of progesterone secretion which increased 10–20 min from the start of perfusion and reached a peak after 30–60 min. A stimulation of progesterone was also observed after perfusion with melatonin (860 pmol/l). The response was evident within 10–30 min of the hormone reaching the corpus luteum and was similar in magnitude to that observed for hCG. The ability of melatonin to stimulate progesterone secretion supports previous in-vitro studies and suggests an ovarian action for melatonin in the primate. The local perfusion system described may have potential uses in studies of luteal function related to aspects of infertility or regulation of fertility. J. Endocr. (1987) 112, 449–457

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