EFFECTS OF THE PRESENCE OF FEMALES ON THE CONCENTRATION OF ANDROGENS IN THE MALE GUINEA-PIG DURING PUBERTY

At weaning (21 days), male guinea pigs were assigned to 3 groups: A, 2 or 3 males with females in separate cages but in the same room; B, 2 males with 1 pubertal female in each cage; and C, males without females in the environment. Animals were sacrificed on the 50th day. Testosterone and androstenedione concentrations in the blood plasma and the testis were estimated by gas chromatography. The body and testicular weights of group C were lower than those of other groups. Testosterone and androstenedione levels in the plasma were lower in group C; testicular concentration of testosterone was similar in group A and C; the level was weak in group B. Testicular concentration of androstenedione was increased in animals isolated from females. In guinea pigs at puberty, the presence or the lack of females modifies testicular weight and androgen concentration.