EFFECTS OF TESTOSTERONE ON CHOLESTEROL LEVELS AND FATTY-ACID COMPOSITION IN THE RAT

The effects of testosterone treatment on cholesterol levels and its fa tty acid components were studied in adult rats. Cholesterol levels inc reased both in the liver and in the serum of castrated rats. Androgen administration restored the normal values only in the serum. A general decrease in unsaturated and essential fatty acids in cholesterol este rs was evident after testosterone administration. In the liver, only t he C16:O/C16:1 ratio clearly increased after testosterone administrati on, which inhibited the DELTA 9 unsaturation of palmitic acid, but not of stearic acid. In the serum the C16:O/C16:1, C18:O/C18:1, and C18:2 /C2O:4 ratios decreased after castration and were restored by testoste rone. The results indicate a clear inhibition of DELTA 9 unsaturation of palmitic and stearic acids, of DELTA 5 unsaturation and elongation in organs other than the liver. No effect was evident on DELTA 6 unsat uration. This suggests that fatty acid unsaturations are regulated dif ferently by testosterone in different tissues. For DELTA 9 unsaturatio n in the liver, the effect also seems to be substrate-dependent.