Synthesis and Secretion of Glycoproteins in Rat Bulbo-Urethral (Cowper’s) Glands. I. The Effect of Copulation on the Glandular Content and on the Incorporation of Galactose and Leucine
Discharge and synthesis of rat bulbo-urethal gland secretory product was studied in ralation to the normal copulatory process. Measurements of the macromolecularly-bound hexose contents in the glands revealed that immediately after the start of sexual intercourse, the glands emitted secretory product independently of the occurrence of ejaculation. Depletion of the glands was completed after 4 h (64% loss of hexose contents), concurrently with an ending of mating. The glands refilled gradually with hexose until after 1 wk hexose contents had returned to the control level. In vivo labeling of the secretory product with 14C-leucine and 3H-galactose at various time intervals after the start of copulation showed that glycoprotein synthesis increased immediately and peaked 6 and 13 h. After about 4 days, synthesis was again near the control level. These trands were accompanied by impressive morphological alterations. In control glands the lumen was filled with secretory product and the cells were studded with secretory granules and contained only scarce cytoplasm. Within 4 h after the start of the intromissions, the glandular lumen was empty and the development of cell structures indicated active formation of secretory product.