A novel follicle-stimulating hormone-induced G alpha h/phospholipase C-delta1 signaling pathway mediating rat sertoli cell Ca2+-influx.
FSH is known to activate Gs/cAMP signaling pathway in Sertoli cells (SCs) to support spermatogenesis. However, the molecular mechanism of FSH-induced Gs/cAMP-independent Ca2+-influx in SCs is not clear. In this study, FSH indeed induced an immediate and dose-dependent intracellular Ca2+-elevation in rat SCs. In the presence of EDTA (2.5 mm) or in the absence of extracellular Ca2+, the FSH-induced intracellular Ca2+-elevation was abolished. The confocal microscopic observation of Ca2+ image revealed that the SC cellular Ca2+ level was gradually increased after 50 sec of FSH treatment. Dantrolene, a blocker of intracellular Ca2+ release, did not affect this FSH-induced intracellular Ca2+ elevation. The pretreatment of rat SCs with phosphatidylinositol-phospholipase C (PLC)-specific inhibitor, U73122 (3 and 10 microm), inhibited the FSH-induced Ca2+-influx in a dose-dependent manner, but treatment with Gs-specific inhibitor, NF449 (0.1 and 0.3 microm), did not. On the other hand, the activation of G alpha h was immediately induced by FSH in the rat SCs within 5 sec of treatment. The translocation of PLC-delta1 from cytosol to cell membrane and the formation of G alpha h /PLC-delta1 complexes occurred within 5 and 10 sec, respectively, of FSH exposure. The intracellular inositol 1,4,5-triphosphate (IP3) production was also detected after 30 sec of FSH treatment. The synthetic peptide of PLC-delta1 (TIPWNSLKQGYRHVHLL), not Gs inhibitor, predominantly inhibited the FSH-induced PLC-delta1 translocation, formation of G alpha h /PLC-delta1 complex, intracellular IP3 production, and Ca2+ influx. In contrast, the peptide did not interfere with FSH-induced intracellular cAMP accumulation. In conclusion, the FSH-induced immediate Ca2+ influx is unambiguously mediated by an alternative G alpha h /PLC-delta1/IP3 pathway that is distinct from the Gs/cAMP pathway in rat SCs.
Lin
Yuan-Feng
YF
Graduate Institute of Pharmaceutical Science, Medical School, Taipei Medical University, Taipei, Taiwan 110, Republic of China.
Tseng
Min-Jen
MJ
Hsu
Hui-Ling
HL
Wu
Yu-Wei
YW
Lee
Yi-Hsuan
YH
Tsai
Yu-Hui
YH
D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005640:Follicle Stimulating Hormone / Q000378:metabolism* / Q000494:pharmacology; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism*; D047468:Immunoprecipitation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D054803:Phospholipase C delta; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D010738:Type C Phospholipases / Q000378:metabolism*
D044385:GTP-Binding Protein alpha Subunits; D007527:Isoenzymes; D011994:Recombinant Proteins; D015544:Inositol 1,4,5-Trisphosphate; D005640:Follicle Stimulating Hormone; D010738:Type C Phospholipases; D054803:Phospholipase C delta; C518026:Plcd1 protein, rat; D002118:Calcium