Follicle-stimulating hormone-induced Galphah/phospholipase C-delta1 signaling mediating a noncapacitative Ca2+ influx through T-type Ca2+ channels in rat sertoli cells.
Our previous study demonstrated that FSH-induced immediate Ca(2+) influx in rat Sertoli cells (SCs) is mediated by the Galphah/phospholipase C-delta1 (PLC-delta1) signaling pathway. As to which Ca(2+) channel is responsible for such Ca(2+) influx was not understood. In this study, thapsigargin triggered an in-store calcium release and evoked a 1.5-fold elevation of intracellular Ca(2+) in Ca(2+)-free media, whereas FSH exhibited no effect. The readdition of CaCl(2) (2.5 mm) to FSH-pretreated or thapsigargin-sensitized SCs in Ca(2+)-free media immediately elicited a rapid Ca(2+) influx or a 2-fold increase of second intracellular Ca(2+) elevation, respectively. The addition of Ca(2+) chelator EGTA (0.2 mm) reduced the FSH-induced elevation of intracellular Ca(2+) in SCs incubated with CaCl(2). However, pretreatment with dantrolene (25 microM), which inhibits in-store calcium release, did not affect the FSH-induced elevation of intracellular Ca(2+). NiCl(2) (10 microM), a T-type calcium channel blocker, abolished the FSH-induced SC Ca(2+) influx. Furthermore, mibefradil (10 and 100 microm), another specific blocker for T-type Ca(2+) channels, dose-dependently suppressed the FSH-induced Ca(2+) influx. In contrast, nifedipine (10 and 50 microm) or omega-conotoxin GVIA (100 and 500 nm), blocker of L- or N-type Ca(2+) channels, respectively, did not affect the FSH-induced SC Ca(2+) influx. On the other hand, FSH-induced Ca(2+) influx was significantly reduced by pretreatment of SCs with myristoylated synthetic peptide (0.1 and 1 microm) of PLC-delta1 fragment TIPWNSLKQGYRHVHLL but not affected by 2',5'-dideoxyadenosine (3 and 15 microm), a selective inhibitor of adenylate cyclase. In conclusion, the FSH-induced Galphah/PLC-delta1 pathway-dependent Ca(2+) influx of rat SCs is mediated by T-type Ca(2+) channels and independent of in-store calcium release.
Division of Reproduction Medicine, Department of Obstetrics and Gynecology, Cathay General Hospital, Taipei, Taiwan 106, Republic of China.
Tsung-Hsuan
TH
Lai
Yuan-Feng
YF
Lin
Feng-Chang
FC
Wu
Yu-Hui
YH
Tsai
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020747:Calcium Channels, T-Type / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008297:Male; D054803:Phospholipase C delta / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects*; D019284:Thapsigargin / Q000494:pharmacology; D011503:Transglutaminases / Q000378:metabolism*
D002121:Calcium Channel Blockers; D020747:Calcium Channels, T-Type; D002614:Chelating Agents; D004791:Enzyme Inhibitors; C527821:Ghalpha protein, rat; D004533:Egtazic Acid; D019284:Thapsigargin; D005640:Follicle Stimulating Hormone; D011503:Transglutaminases; D054803:Phospholipase C delta; D019204:GTP-Binding Proteins; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases; D002118:Calcium