Interleukin-1 inhibits cholesterol side-chain cleavage cytochrome P450 expression in primary cultures of Leydig cells.
Interleukin-1 (IL-1) is a potent inhibitor of Leydig cell function. We have reported that IL-1 inhibited hCG-induced cAMP and testosterone formation. In the present study we evaluated the effect of IL-1 on Leydig cell cholesterol side-chain cleavage cytochrome P450 (P450scc) mRNA levels. P450scc is the rate-limiting enzyme for Leydig cell steroidogenesis. Highly purified Leydig cells were prepared from adult Sprague-Dawley male rats (55-65 day-old) using the combination of elutriation and Percoll gradient. Purified Leydig cells were then cultured with or without IL-1 beta (1-100 ng/ml) and recombinant human monocyte-derived IL-1 receptor antagonist (250 ng/ml) for 24 h. hCG (10 ng/ml), 8-bromo-cAMP (0.1 mM), or 4 beta-phorbol 12 beta-myristate 13 alpha-acetate was then added, and cultures were continued for an additional 6 h. P450scc mRNA levels of Leydig cells were very low to undetectable after 24 h in culture and could be stimulated by the addition of either hCG (10 ng/ml) or 8-bromo-cAMP (0.1 mM), but the addition of 4 beta-phorbol 12 beta-myristate 13 alpha-acetate had no effect. P450scc mRNA levels increased as early as 2 h after the addition of hCG. Furthermore, cycloheximide (1 microgram/ml) markedly blocked hCG-induced P450scc mRNA expression. This indicates that synthesis of a labile new protein(s) is required for the induction of P450scc mRNA by hCG. IL-1 beta inhibited hCG-stimulated testosterone formation and P450scc mRNA expression in a dose-dependent manner. The inhibitory effects of IL-1 beta could be reversed by the concomitant addition of IL-1 receptor antagonist. Our results suggest that P450scc mRNA levels of Leydig cells are modulated by IL-1. This may be one mechanism that could explain the inhibitory effects of IL-1 on Leydig cell steroidogenesis.
Lin
T
T
Medical Service, W.J.B. Dorn Veterans Hospital, School of Medicine, Columbia, South Carolina.
Wang
T L
TL
Nagpal
M L
ML
Calkins
J H
JH
Chang
W W
WW
Chi
R
R
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000199:Actins / Q000235:genetics; D000818:Animals; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D007985:Leydig Cells / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000199:Actins; D006063:Chorionic Gonadotropin; D007375:Interleukin-1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D015124:8-Bromo Cyclic Adenosine Monophosphate; D002786:Cholesterol Side-Chain Cleavage Enzyme; D013755:Tetradecanoylphorbol Acetate