5α-Androstenone and Testosterone in Peripheral Plasma of the Boar During and Following Copulation

Copulation was generally followed by increases in peripheral plasma 5α-androstenone and testosterone levels lasting for periods of about 60 to 100 min. The effect of copulation on the plasma levels of these steroids did, however, vary between boars. In seven out of eight boars the maximum levels of 5α-andro-stenone in the period 60 to 100 min. after copulation were from 114 to 218 % (mean 150 %) of the levels in samples collected before copulation. The corresponding figures for testosterone were from 104 to 283 % (mean 190 %). One boar showed decreasing plasma steroid levels after copulation.The coefficient of correlation between the peripheral plasma levels of 5α-androstenone and testosterone was found to be + 0.61 (n = 2.03).