THE INHIBITORY EFFECT OF OXYTOCIN AND COLCHICINE ON THE VENTRAL PROSTATE OF ADULT-RATS

Oxytocin (OT) was previously reported to have a tropic effect on the e pithelial component of the ventral prostate in orchiectomized rats, wh ile in intact rats it was ineffective. The goal of the present study w as to obtain more information about the factors interfering with the p rostate response to this peptide. Wistar rats received daily s. c. inj ections of synthetic OT (0.25 IU/100 g) for 3 consecutive days and wer e killed 6 hours later. For one group of animals the last injection wa s supplemented with colchicine (0.1 mg/100 g). In intact rats OT affec ted the prostate gland only when applied in combination with colchicin e. This treatment caused a reduction of epithelial height, the volume density and the total volume of the epithelium, whereas an enhancement of the volume density and the mean diameter of the acionar lumen was recorded. Glandular noradrenaline content was decreased. These changes demonstrated a diminished secretory activity of the glandular epithel ium and suppression of expelling the secretion. It seems that this eff ect was achieved by synergistic action of OT and colchicine at the lev el of the sympathetic control of the gland.