Ultrastructural and histochemical aspects of prostatic secretion in dog

The reaction of canine prostatic epithelium was studied ultrastructurally and histochemically (acid phosphatase, zinc) in mature Beagle-dogs 15 minutes after intravenous application of pilocarpine (1 mg/kg body weight). In the normal prostate we found only merocrine secretion with exocytosis of secretory granules. Exocytosis persisted after stimulation with pilocarpine, but was quantitatively greatly increased. Apocrine or holocrine types of secretion were neither found under resting conditions nor under extreme functional stress of the glandular epithelium. Histochemically a distinct decrease of the activity of acid phosphatase and of zinc in the apical part of the epithelium has developed, which corresponds to the ultrastructurally obvious loss of secretory granules.