Relaxin and prostaglandin on oxytocin secretion from bovine luteal cells during different stages of gestation

1990 ◽  
Vol 122 (3) ◽  
pp. 396-402 ◽  
Author(s):  
Al-Hassan I. Musah ◽  
Christian Schwabe ◽  
Lloyd L. Anderson

Abstract The objective of this study was to determine whether bovine luteal cells from different stages of gestation secrete oxytocin and whether relaxin, cloprostenol (a potent analogue of prostaglandin F2α), estradiol-17β, and LH can acutely alter oxytocin secretion. Bovine luteal cells (105) were cultured for 24 h without treatment and with medium-hormone replacement every 24 h. Oxytocin was quantified by radioimmunoassay of the culture media. Basal oxytocin secretion was similar (22-31 pmol/l, p>0.05) for all stages of gestation (days 100, 145, 160, 185, 200, 210, and 240). Relaxin induced a dose-dependent suppression of oxytocin release. After 24 h of incubation, addition of 0, 16.7, 83.5, and 167 nmol/l porcine relaxin (3000 U/mg) induced 54 ± 4, 105 ± 16, 47 ± 4, and 38 ± 4 pmol/l of oxytocin in cells from 160-day-old corpora lutea and 138 ± 12, 21 ± 2, 19 ± 3, and 15 ± 2 pmol/l oxytocin in cells from 240-day-old corpora lutea. From luteal cells of 160- and 240-day-old corpora lutea, 2 μmol/l cloprostenol induced a marked increase (p<0.01) of 208 ± 39 and 371 ± 34 pmol/l oxytocin, respectively. Addition of 167 nmol/l relaxin did not prevent cloprostenol-induced oxytocin secretion during the first 48 h, but a decrease (p<0.05) in oxytocin occurred in day 3 cell cultures. These results indicate that cultured luteal cells obtained from different stages of gestation in cattle can secrete oxytocin and suggest a role for relaxin in the regulation of oxytocin release.

1989 ◽  
Vol 121 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Werner Schlegel ◽  
Dieter Daniels

Abstract. Luteal cells were isolated from pseudopregnant rabbits on days 3, 6, 9, 12 and 15 post ovulation. Prostaglandin concentration and the activities of the enzymes prostaglandin E-2-9-ketoreductase and prostaglandin-15-hydroxydehydrogenase were determined. Luteal cells from day 7 and 12 of pseudopregnancy were maintained in culture for 24 h and then exposed to a mixture of [1-14C]PGE2 (70 μmol/l) in the presence or absence of estradiol-17β. After a 24 h incubation period, the culture medium was adjusted to pH 3.5, immediately extracted and analysed for PG. Cultured luteal cells were able to convert exogenously applied PGE2 to PGF2α and to metabolize both PGs. Primary PGs as well as their metabolites 15-keto PGE2, 15-keto PGF2α, 13,14 dihydro15-keto PGE2, and 13,14 dihydro-15-keto PGF2α were detected in the culture medium and in the cells. The addition of estradiol-17β together with PGE2 caused a significant reduction in the PGE2-9-ketoreductase mediated PGF2α synthesis, whereas the metabolism of PGE2 remained unchanged. This inhibitory effect of estradiol-17β was dose-dependent on day 12 of pseudopregnancy. The results demonstrate that isolated rabbit luteal cells are able to synthesize and metabolize the luteolytic factor PGF2α. Whether the inhibitory effect of estradiol-17β may have any physiological relevance has to be examined in further studies.


1992 ◽  
Vol 133 (3) ◽  
pp. 451-458 ◽  
Author(s):  
T. Endo ◽  
H. Watanabe ◽  
H. Yamamoto ◽  
S. Tanaka ◽  
M. Hashimoto

ABSTRACT While prostaglandin F2α (PGF2α) has been thought to be a natural luteolysin in non-primates, a luteolytic effect in the human corpus luteum is less evident. We therefore investigated the action of PGF2α on monolayer cultures of human luteal cells obtained from mid-luteal phase corpora lutea. PGF2α increased basal and human chorionic gonadotrophin (hCG)-stimulated progesterone production by human cultured luteal cells. A potent tumour-promoting phorbol ester, phorbol 12-myristate-13-acetate (PMA), also stimulated progesterone production by cultured human luteal cells. Although human luteal cells were incubated for 24 h with PMA, hCG was still able to stimulate the production of progesterone by PMA-pretreated cells. However, PMA pretreatment blocked the ability of PGF2α to stimulate progesterone production. It is possible that the luteotrophic effect of PGF2α may be mediated, in part, by the activation of protein kinase C. Addition of PGF2α to suspensions of human luteal cells preincubated with myo-[2-3H]inositol promoted an increase in labelled inositol phosphates. PGF2α also rapidly increased intracellular free Ca2+ in human luteal cells loaded with the fluorescent Ca2+ probe, fura-2. We conclude that PGF2α and PMA stimulate progesterone production and that PGF2α increases the intracellular free calcium and inositol phosphates of human cultured luteal cells in the mid-luteal phase. Journal of Endocrinology (1992) 133, 451–458


1990 ◽  
Vol 126 (2) ◽  
pp. 245-253 ◽  
Author(s):  
C. A. McArdle

ABSTRACT Oxytocin is synthesized in the granulosa-derived large cells of the ruminant corpus luteum from a gene which is dramatically up-regulated in the first few days after ovulation. In this work, the regulation of granulosa and luteal cells by prostaglandins and insulin (or insulin-like growth factor-I; IGF-I) has been explored by comparing their effects on oxytocin and progesterone production in cell culture. In granulosa cells, chronic exposure to insulin (17 nmol/l) stimulated luteinization as indicated by increased release of oxytocin and progesterone. Prostaglandin F2α (PGF2α) alone had little effect, but synergized with insulin (or IGF-I) to increase the release of both these hormones. In direct contrast, insulin-stimulated oxytocin production by luteal cells was inhibited by PGF2α. The half-maximal dose (EC50) for PGF2α action in both cell preparations was similar (10–100 nmol/l). Dose–response studies revealed that PGF2α increased the potency of insulin in granulosa cells (EC50 for insulin-stimulation of oxytocin release reduced from 141 to 13 nmol/l by 1 μmol PGF2α/l), but not in luteal cells. Insulin-stimulated oxytocin release from granulosa cells was also synergistically increased by PGE1, PGE2 and forskolin, suggesting this effect to be mediated by adenylate cyclase-coupled PGE receptors. The results reveal that the effects of prostaglandins on oxytocin release are dependent on both the developmental stage of the target tissue and on the presence of other regulators of cellular differentiation. Moreover, they suggest that the increase in responsiveness to insulin and IGF-I, which appears to accompany luteinization in the cow, may be an effect of prostaglandins produced locally during the peri-ovulatory period. Journal of Endocrinology (1990) 126, 245–253


Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 179
Author(s):  
Michał M. Hryciuk ◽  
Katarina Jewgenow ◽  
Beate C. Braun

The objective of this study was to investigate the effect of luteinizing hormone (LH) on steroidogenic luteal cells obtained from corpora lutea (CL) of the domestic cat and selected wild felids. Luteal cells were isolated enzymatically from CL at different developmental stages and cultured for two days in the presence and absence of 100 ng/mL LH, respectively. Functionality was assessed by progesterone (P4) accumulation in cell culture media determined by ELISA. In addition, steroidogenic function was confirmed using immunohistochemistry for 3β-hydroxysteroid dehydrogenase (HSD3B). The enzymatic method allowed for the isolation of mostly small luteal cells in all investigated felids. Treatment with LH resulted in an increase in P4 secretion of cultured luteal cells obtained from CL in the formation stage (African lion) and development/maintenance stage (domestic cat (p < 0.05), Javan leopard), whereas luteal cells from more advanced stages of luteal development (regression) responded moderately or not at all to LH stimulation (domestic cat, Asiatic golden cat, Asiatic lion). The protein signal for HSD3B on CL was visible until development/maintenance. In conclusion, this study shows that LH promotes P4 production in luteal cells only until the onset of regression, when morphological signs are visible on the CL of felids and HSD3B is no longer detectable.


1995 ◽  
Vol 147 (1) ◽  
pp. 177-182 ◽  
Author(s):  
M Vega ◽  
I Carrasco ◽  
T Castillo ◽  
J L Troncoso ◽  
L A Videla ◽  
...  

Abstract To evaluate the effect of reactive oxygen species in human corpus luteum function, we investigated whether hydrogen peroxide (H2O2) affects the in vitro luteal cell production of steroids. H2O2 treatment (1·0–100 μm) of mid and late luteal cell cultures elicited a dose-dependent decrease in basal progesterone production. However, treatment of mid luteal cells with a low concentration of H2O2 0·01 μm) significantly stimulated progesterone secretion (P<0·05). In addition, H2O2 (100 μm) markedly inhibited human chorionic gonadotropin (hCG)-stimulated progesterone and estradiol secretion. cAMP production was enhanced (2·4-fold, P<0·05) by hCG treatment of luteal cells. The addition of H2O2 (0·1–100 μm) to hCG-stimulated luteal cell cultures elicited a decrease in cAMP concentration (P<0·05) and in the specific binding of radiolabeled hCG by luteal cells. Progesterone and estradiol production stimulated by dibutyryl cAMP were significantly inhibited by H2O2 (P<0·05). These findings suggest that H2O2 interferes with basal steroid production and, in hCG-stimulated conditions, it may inactivate the gonadotropin–receptor complex. The anti-steroidogenic action of H2O2 therefore raises the possibility of a modulatory role of H2O2 in human luteal steroidogenesis. Journal of Endocrinology (1995) 147, 177–182


1992 ◽  
Vol 127 (3) ◽  
pp. 246-251 ◽  
Author(s):  
Yasunori Yoshimura ◽  
Yukio Nakamura ◽  
Fumitaka Ichikawa ◽  
Takahisa Oda ◽  
Masao Jinno ◽  
...  

The present study was undertaken to assess the ability of human corpora lutea to produce leukotriene B4 (LTB4). The maximum capacity of luteal cells to secrete progesterone was attained on day 4, and both the basal production and the responsiveness to hCG decreased thereafter. In contrast, the production of LTB4 by cultured luteal cells was significantly reduced on day 4, but increased thereafter. The basal concentration of LTB4 produced by luteal cells varied from 75 to 590 pg/105 cells/2 days. LTB4 production appeared to decrease concomitantly with increased-progesterone production in cultured luteal cells. Exposure to hCG decreased significantly LTB4 production by cultured luteal cells on day 4. An inhibitor of the lipoxygenase pathway, nordihydroguaiaretic acid (NDGA), inhibited LTB4 production in a dose-dependent manner. However, NDGA did not affect basal progesterone production by the cultured luteal cells. A significant inverse relationship existed between the accumulation rates of progesterone and LTB4 in the luteal cells. Furthermore, the addition of LTB4 inhibited progesterone production in a dose-dependent manner in both the presence and absence of hCG. In conclusion, LTB4 could be synthesized by human corpora lutea in vitro, and correlated inversely with the secretion rates of progesterone. These data suggest that LTB4 produced locally in the corpus luteum may be an important regulator in human luteal regression.


1968 ◽  
Vol 59 (2_Suppl) ◽  
pp. S35-S51 ◽  
Author(s):  
B. L. Lobel ◽  
E. Levy

ABSTRACT Activities of various hydrolases and dehydrogenases were studied during the formation, development and involution of cyclic corpora lutea and in the corpora lutea of early pregnancy. At 24 hours postovulation the luteal cells, whether of granulosal or thecal origin, contained demonstrable levels of Δ5-3β-hydroxysteroid dehydrogenase and the NADP and NADPH2 diaphorases. During the period of proliferation and cellular growth, enzymic activities in the luteal cells were moderate at first, and then increased. In the mature corpus luteum, activities of the dehydrogenases occurred in all luteal cells but were most intense in the large polymorphic luteal cells. Activities of hydrolytic enzymes, low in the immediate postovulatory period, increased with the development of the vascular system. Enzymic characteristics of corpora lutea of gestation were similar to those of cyclic corpora, except for phosphorylase activity which was observed in luteal cells in gestational corpora, but confined to the vascular walls in cyclic corpora. No increase in activities of 17β- and 20β-hydroxysteroid dehydrogenases (above those seen in pre-ovulatory follicles) were observed after incubation of sections of either mature cyclic or gestational corpora. Involution of cyclic corpora lutea began with degenerative changes in the blood vessels: pyknosis of the endothelial cell nuclei and a sudden decline in activities of hydrolytic enzymes in the vascular walls. Subsequently, the luteal cells showed a sharp decrease in activities of the dehydrogenases as well as other signs of regressive change. The cytochemical findings are discussed in relation to biochemical observations on steroid synthesis by the bovine corpus luteum.


1986 ◽  
Vol 113 (4) ◽  
pp. 570-575 ◽  
Author(s):  
Firyal S. Khan-Dawood

Abstract. Immunoreactive oxytocin is detectable in the corpora lutea of women and cynomolgus monkeys by radioimmunoassay. To localize the presence of oxytocin and neurophysin I in ovarian tissues of subhuman primates, three corpora lutea and ovarian stromal tissues and two Fallopian tubes obtained during the menstrual cycle of the baboon and decidua from two pregnant baboons were examined using highly specific antisera against either oxytocin or neurophysin I and preoxidase-antiperoxidase light microscopy immunohistochemistry. Oxytocin-like as well as neurophysin I-like immunoreactivities were found in some cells of all the corpora lutea only, but could not be demonstrated in ovarian stromal tissues, Fallopian tubes and decidua. Specificity of the immunocytochemical reaction was further confirmed by immunoabsorption of the antiserum with excess oxytocin or neurophysin, after which the immunoreactivities for both oxytocin and neurophysin in the luteal tissue were negative. Similar controls using normal rabbit serum gave no positive staining for either oxytocin or neurophysin. Counterstaining of the positive immunoreactivities for oxytocin and neurophysin I with Mayer's haematoxylin and eosin demonstrated clearly that the oxytocin and neurophysin I appeared as granular material mainly within the cytoplasm of the luteal cells. The localization of immunoreactive oxytocin and neurophysin I in the corpus luteum of the baboon demonstrates directly the presence of these two neurohypophysial peptides within primate luteal cells and suggests their local production.


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