Nonesterified fatty acids modulate steroidogenesis in mouse Leydig cells.
The effects of nonesterified fatty acids (NEFA) in modulating testosterone synthesis stimulated by luteinizing hormone (LH, 10 ng/sample) were investigated in isolated adult mouse Leydig cells. LH-stimulated testosterone production was inhibited by triglycerides (0-500 mg/dl, 50 mg/dl, 94% of the control and 500 mg/dl, 40%) and by a mixture of NEFA (100 microM, 70% of control, 200 microM, 54%, and greater than 200 microM, less than 50%). Oleic acid was a more potent inhibitor than linoleic, stearic, or palmitic acids. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP, 5 mM) stimulated testosterone production comparable to LH but failed to reverse the inhibition of steroidogenesis produced by the NEFA. The inhibition produced by NEFA was dependent on extracellular Ca2+; and a Ca2+ channel antagonist, verapamil (10 microM), enhanced the inhibition of chylomicrons and fatty acids. 22(R)-hydroxycholesterol (10 microM) reversed the inhibition produced by NEFA. The inhibitory effects of NEFA were reversible by removal of the fatty acids. The results indicate that NEFA are potent modulators of testosterone synthesis in Leydig cells stimulated with either LH, cAMP, or intracellular Ca2+. NEFA inhibit steroidogenesis at one of the steps preceding conversion of cholesterol to pregnenolone.
Meikle
A W
AW
Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City 84132.
Benson
S J
SJ
Liu
X H
XH
Boam
W D
WD
Stringham
J D
JD
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002914:Chylomicrons / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology*; D006888:Hydroxycholesterols / Q000494:pharmacology; D007700:Kinetics; D007985:Leydig Cells / Q000187:drug effects / Q000378:metabolism*; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D051379:Mice; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D011863:Radioimmunoassay; D013739:Testosterone / Q000096:biosynthesis*; D014700:Verapamil / Q000494:pharmacology
D002914:Chylomicrons; D005230:Fatty Acids, Nonesterified; D006888:Hydroxycholesterols; D008041:Linoleic Acids; D009829:Oleic Acids; C003585:22-hydroxycholesterol; D015124:8-Bromo Cyclic Adenosine Monophosphate; D019301:Oleic Acid; D013739:Testosterone; D007986:Luteinizing Hormone; D019787:Linoleic Acid; D014700:Verapamil; D000242:Cyclic AMP; D002118:Calcium