Plasma luteinizing hormone and testosterone levels were determined in 16 normal adult males during a period of acute alcohol intoxication. Plasma testosterone levels were in the normal range for adult males prior to alcohol administration. Plasma testosterone levels began to fall during the ascending phase of the blood alcohol curve but plasma luteinizing hormone levels did not change significantly. At peak blood alcohol levels [109 +/- 4.6 (S.D.) mg/100 ml], plasma testosterone was significantly depressed and a significant increase in plasma luteinizing hormone values occurred. During the descending phase of the blood alcohol curve, plasma testosterone levels remained depressed and plasma luteinizing hormone levels decreased toward base-line values. These data indicate that acute alcohol intake produces a suppression of plasma testosterone via peripheral mechanisms which regulate the biosynthesis and/or biotransformation of the steroid. The surge in luteinizing hormone values at peak levels of intoxication are most likely due to stimulation of gonadotropin secretion via "long loop" mechanisms associated with low levels of plasma testosterone.