Effects of GnRH Mobilization and on Protein Kinase C Activity, Ca2-' Steroidogenesis of Human G ranulosa Cells
نویسندگان
چکیده
Gonadotropin-releasing hormone (GnRH) and its agonists have been known to directly affect steroid hormone production in human granulosa cells. In this study, we examined effects of GnRH on Ca2+ mobilization, protein kinase C activity and steroidogenesis of human granulosa cells. Human granulosa cells were harvested by aspiration of follicles during oocyte retrieval for IVF. Test substances, that is, GnRH agonist ([D-Ser(TBu)6]-LHRH-EA),12-0-tetradecanoyl-phorbol-13-acetate (TPA), A23187, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) and nordihydroguaiaretic acid (NDGA) were added to HTF medium with human granulosa cells. At the end of a 5-h incubation period, progesterone and estradiol in the medium were extracted and measured. GnRH agonist (10-9M and 10-8M) significantly stimulated (P<0.05) progesterone and estradiol accumulation in the medium. TPA (10-7M, 10-8M and 10-9M) also significantly stimulated (P<0.05) progesterone accumulation. A23187 (10-6M) significantly stimulated progesterone accumulation (P<0.05) and significantly enhanced (P<0.05) the stimulatory effect of TPA on progesterone production. H-7 (10-3M,10-4M and 10-5M) and NDGA (10-3M, 10-4M and 10-5M) significantly inhibited (P<0.05) the effect of GnRH agonist on progesterone and estradiol production by the granulosa cells. The granulosa cells were loaded with 4 ,uM Fura 2-AM, and the ratio of the intensities of fluorescent emission at 510 nm with excitation at 340 and 380 nm was calculated at 100-ms intervals. GnRH agonist (10-7M and 10-6M) increased (P<0.05) [Ca2+]i significantly as compared with the control. These results suggested that the effects of GnRH on progesterone and estradiol production in human granulosa cells were mediated partially by calcium mobilization and partially by C-kinase activity, and protein kinase C, [Ca2+]i and lipoxygenase were suspected of being important intracellular messages for GnRH in human granulosa cells.
منابع مشابه
A Comparative study of synthetic carp GnRH and carp pituitary homogenate effects on in vitro steroidogenesis of oocytes in common carp (Cyprinus carpio)
Vitellogenic stage carp ovaries were collected aseptically and the cells of ovarian follicles were dispersed by trypsin treatment and cultivated as monolayer. Control cultures were grown in medium M199 alone. Media for experimental cultures were supplemented either with 100 µl ml-1 of CPH and CPS-carp GnRH (cultivated pituitary cell secretion affected by 10-6, 10-8, 10-10 M carp GnRH). The dire...
متن کاملA Comparative study of synthetic carp GnRH and carp pituitary homogenate effects on in vitro steroidogenesis of oocytes in common carp (Cyprinus carpio)
Vitellogenic stage carp ovaries were collected aseptically and the cells of ovarian follicles were dispersed by trypsin treatment and cultivated as monolayer. Control cultures were grown in medium M199 alone. Media for experimental cultures were supplemented either with 100 µl ml-1 of CPH and CPS-carp GnRH (cultivated pituitary cell secretion affected by 10-6, 10-8, 10-10 M carp GnRH)....
متن کاملStimulation of Jun N-terminal kinase (JNK) by gonadotropin-releasing hormone in pituitary alpha T3-1 cell line is mediated by protein kinase C, c-Src, and CDC42.
The signaling of ligands operating via heterotrimeric G proteins is mediated by a complex network that involves sequential phosphorylation events. Signaling by the G protein-coupled receptor GnRH was shown to include elevation of Ca2+ and activation of phospholipases, protein kinase C (PKC) and extra-cellular signal-regulated kinase (ERK). In this study, GnRH was shown to activate Jun N-Termina...
متن کاملCarvacrol and Thymol Attenuate Cytotoxicity Induced by Amyloid β25-35 Via Activating Protein Kinase C and Inhibiting Oxidative Stress in PC12 Cells
Background: Our previous findings indicated that carvacrol and thymol alleviate cognitive impairments caused by Aβ in rodent models of Alzheimer's disease (AD). In this study, the neuroprotective effects of carvacrol and thymol against Aβ25-35-induced cytotoxicity were evaluated, and the potential mechanisms were determined. Methods: PC12 cells were pretreated with Aβ25-35 for 2 h, followed by ...
متن کاملRegulation of neurite outgrowth from differentiated human neuroepithelial cells: a comparison of the activities of prothrombin and thrombin.
The mechanism by which thrombin and prothrombin control neurite retraction was studied in Ad12E1HER10 human neuroepithelial cells. Morphological changes in differentiated cells were apparent within minutes of the addition of very low concentrations of thrombin (3 pM). Higher concentrations (2 nM) of prothrombin were required to elicit a similar response. Doses of thrombin and prothrombin suffic...
متن کامل