Influence of conspecific males on the oestrous cycle of underfed female mice.

Female mice maintained on restricted diet (3.5, 3.0 and 2.5 gm/female/day) exhibited disturbances in the oestrous cycle which were directly related to the degree of diet restriction. Females maintained on restricted diet, 2.5 gm/day, showed complete suppression of the oestrous cycle. The presence of a conspecific male was effective in maintaining normal oestrous cycles in underfed females to some extent. It is suggested that the ability of males to maintain oestrous cycle in underfed females is due to the stimulatory influence of the male-originating pheromone on hypophysial gonadotrophin secretion.