The effects of androgen on the activities of esteropeptidase and delta 4-3-ketosteroid 5 alpha-reductase were investigated. Ratios of the denervated side to the non-operated side for gland weight and esteropeptidase activity were higher in androgenized females than in untreated females. The specific activities of 5 alpha-reductase were increased by denervation but the total activities were decreased. The results suggest that parasympathectomy leads to higher androgen responsiveness in the rat submandibular gland, which relates to the observed reduction in weight loss of the gland and the increases in its esteropeptidase activities.