Adrenal-oestrous Relationships in Grouped or Isolated Female Mice

Abstract

GROUPING females together often suppresses oestrous cycles in mice if females are maintained in an environment free of male odour^1,2. Such suppression may take the form of either an increased incidence of spontaneous pseudopregnancy or, more commonly, a general prolongation of the dioestrous phase of the cycle. This kind of induced pseudopregnancy is greatly reduced by olfactory lobectomy^3,4, but the dioestrous response to grouping has not been unequivocally established as an olfactory-mediated effect. A separate body of literature, dealing largely with all male or mixed sex groups of mice, has emphasized a concept that relates the neurogenic stressors associated with high density (social stress) to increased release of adrenocorticotrophin and a concurrent depression of circulating gonadotrophin⁵. Specificity of sensory mediation has not been of real interest in these studies.