A new target for growth hormone releasing-hormone action in rat: the Sertoli cell.
A GHRH-like mRNA and peptide (t-GHRH) have been detected in rat and human testis. In rat, t-GHRH mRNA is localized to developing spermatogenic cells. We predicted that the most likely target cell of t-GHRH action would be the Sertoli cell. To test this prediction, we evaluated GHRH action on Sertoli cell function. Rat GHRH at a concentration of 10 nM or 100 nM stimulated cAMP production 2-fold over control levels after a 30 min incubation. This stimulation was obliterated by preincubation with a 10-fold excess of the GHRH antagonist (N-Ac-Tyr1, D-Arg2)-GRF(1-29)-NH2. The effect of treatment with [His1,Nle27]GHRH(1-32)-NH2, a GHRH analog, on Sertoli cell mRNAs was also assessed. Treatment with the analog significantly increased levels of c-fos and steel factor (the product of the Steel gene, also termed SCF) mRNAs above controls, but had no effect on sulfated glycoprotein-2 mRNA. We conclude that GHRH acts via adenylate cyclase to modulate specific Sertoli cell products, possibly as part of a network of local interacting factors controlling Sertoli and germ cell function.
Srivastava
C H
CH
Section of Endocrinology/Diabetology, Indiana University Medical Center, Indianapolis 46202.
Breyer
P R
PR
Rothrock
J K
JK
Peredo
M J
MJ
Pescovitz
O H
OH
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos / Q000235:genetics; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000187:drug effects* / Q000502:physiology; D019089:Stem Cell Factor
D016298:Hematopoietic Cell Growth Factors; D012333:RNA, Messenger; D019089:Stem Cell Factor; D013007:Growth Hormone-Releasing Hormone; D000242:Cyclic AMP; D000262:Adenylyl Cyclases