Arginine vasopressin stimulates phosphoinositide turnover in an enriched rat Leydig cell preparation.
An enriched rat Leydig cell preparation was preincubated with [14C]arachidonic acid. Stimulation of the cells with arginine vasopressin (AVP) (1 microM) for 2 min caused a significant increase in labelled phosphatidic acid and a significant fall in radioactivity in phosphatidylinositol and phosphatidylinositol 4-monophosphate + phosphatidylinositol 4,5-bisphosphate. Preincubation with dibutyryl cyclic AMP had no effect on the AVP-induced phospholipid turnover. Leydig cells were preincubated with myo-[2-3]inositol for 22 h and then with 10 mM LiCl for 10 min. Exposure to AVP (1 microM) induced a rise in labelled inositol phosphates. The response was inhibited when the cells were preincubated with the phorbol ester, 4 beta-phorbol 12-myristate 13-acetate (0.16 microM) for 10 min. These results provide evidence for an AVP-induced phospholipase C stimulation in rat Leydig cells and suggest a protein kinase C-dependent feedback inhibition of the stimulation. Other agonists that might have a regulatory function in the testis were tested for possible effects on phosphoinositide metabolism. Of prostaglandin E2 (10 microns,) angiotensin II (0.1 microM), and bradykinin (0.9 microM), only the latter induced a significant increase in the labelled inositol phosphates. This suggests that Leydig cells possess a bradykinin receptor which can activate phospholipase C.
Nielsen
J R
JR
PharmaBiotec Research Center, Royal Danish School of Pharmacy, Copenhagen, Denmark.
Hansen
H S
HS
Jensen
B
B
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002478:Cells, Cultured; D007985:Leydig Cells / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010718:Phosphatidylserines; D001127:Arginine Vasopressin