Effects of a high-fat diet on postabsorptive and postprandial testosteroneresponses to a fat-rich meal

Postprandial testosterone concentrations have been shown to significantly d ecrease after a fat-rich meal, which may be due to inhibition of testostero ne production by chylomicrons. We examined the effects of a high-fat diet k nown to reduce postprandial chylomicrons on the testosterone response to a fat-rich meal. Total testosterone (TT), free testosterone (FT), cortisol, a nd insulin responses to a high-fat test meal containing 5.44 MJ (1,300 kcal , 11% carbohydrate, 3% protein, 86% fat) were determined before (week 0) an d after (week 8) an 8-week high-fat diet (64% fat) in 11 healthy men. The h igh-fat diet resulted in significant reductions in postabsorptive and postp randial serum triacylglycerols (55% and 50%, respectively). There were no s ignificant changes in postabsorptive serum TT, FT, and cortisol, but insuli n concentrations were significantly (P less than or equal to .05) lower at week 8 (-28%). There was a significant reduction 1 hour after the fat-rich meal for TT (-22%) and FT (-23%), which remained significantly below baseli ne for 8 hours. Postprandial TT and FT responses were not significantly dif ferent after the 8-week high-fat diet. Postprandial serum cortisol concentr ations were significantly reduced 1 hour after the meal. There were no sign ificant differences before and after the high-fat diet. Insulin was signifi cantly increased at the 0-, 1-, and 2-hour postprandial time points before and after the high-fat diet. Compared with week 0, insulin concentrations w ere significantly lower prior to and immediately after the fat-rich meal at week 8. These data indicate a fat-rich meal results in a prolonged reducti on in TT and FT concentrations that is not altered by lowering postprandial chylomicrons. Alternative mechanisms (eg, higher uptake at the receptor le vel of cells) other than chylomicron-induced or insulin-induced inhibition of steroidogenesis are likely responsible for the reduction in TT and FT af ter a fat-rich meal. Copyright (C) 2001 by W.B. Saunders Company.