Sexual dimorphism in rat submaxillary gland

: The existence of sexual dimorphism (SDM) in tubules and acini of the submaxillary gland was investigated in male and female 60 day-old Wistar rats. Conventional histology was followed by evaluation of 1) Percentage of area occupied by tubules, acini, and other tissues and 2) Tubular area, employing a semi-automatic image analyser. The granular tubules of male rats were larger than those of females. This statistically significant difference indicates the existence of SDM from a morphological viewpoint. Castration seems to abolish these differences by inducing involution of tubular tissue in males. Whereas treatment with testosterone seems to reconstitute tubular tissue in castrated males, a similar dose of estradiol benzoate elicits a reduction in tubular size in ovariectomized females.