Adrenocortical and Gonadal Responses of Female Mice to Increased Population Density

Abstract

Nulliparous and parous female mice of albino and wild-stock strains were maintained in groups and isolated. Mild hyperplasia of the zonae fasciculata-reticularis and increased involution of the X-zone of the adrenal cortex, significantly lower uterine weight, and questionable increases in splenic and ovarian weight were associated with grouping. Adrenal weight was not changed as the alterations in the fasciculata and X-zone evidently off-set each other. Degree of cortical hyperplasia does not account for the magnitude of response to increased density seen in populations of mixed sex. It is suggested that an increase of adrenal androgens may account for accelerated involution of the X-zone and inhibition of reproductive function.