Sexual differences in the distribution of epithelial alterations in vitamin A-deficient rats.

Male and female rats maintained on a vitamin A-deficient diet showed sex-related differences in several pathological features. Males developed severe manifestations of hypovitaminosis A earlier than females. They also presented more extensive squamous metaplasia of the trachea and more severe sialoadenitis, especially of the submaxillary gland. Females, on the other hand, presented earlier and more extensive squamous metaplasia of the renal pelvis. The underlying causes of sexual dimorphism in these pathological features are not known, but hormonal influences are suggested.