Bisexual Mating Behavior in the Male Rat: Effects of Castration and Hormone Administration

Abstract

One [male] rat which was an unusually vigorous copulator when placed with [female][female] in heat was observed to display all elements of the feminine mating pattern when mounted in sexual fashion by other[male][male] . The exptl. animal was highly aggressive and frequently attacked stimulus [male][male] after they had mounted him and elicited feminine reactions. Castration was followed by the immediate loss of feminine mating reactions, and masculine copulatory behavior and aggressiveness disappeared somewhat later. Injns. of testosterone propionate restored copu- lation, the power of ejaculation, and aggressive reactions; and also revived all aspects of the feminine mating pattern. Injns. of estrogen and progesterone evoked copulatory behavior without ejaculation, and called forth all of the estrous responses. The bearing of the foregoing observations upon general concepts of the neurohormonal basis for sexual behavior is discussed.