DECREMENT OF BLOOD-FLOW PRECEDES THE INVOLUTION OF THE VENTRAL PROSTATE IN THE RAT AFTER CASTRATION

Blood flow to the rat ventral prostate (VP), dorsolateral prostate (DP ), and Dunning R3327 prostatic tumors was measured at different times up to 7 days after castration, using the microsphere method. In the VP organ weight was decreased from day 3 onwards. Blood flow was, howeve r, already significantly decreased from day 1. The reduced blood flow in VP in 1-3 and 7-day castrated animals could be reversed by testoste rone treatment. Organ weight was slightly decreased but blood flow was unaffected by castration in DP. Castration left Dunning tumor volume and blood flow unaffected. Using immunohistochemistry, androgen recept ors were observed in epithelial and stromal cells in VP, DP and Dunnin g tumors, but not in blood vessels. Castration is known to induce apop tosis in the VP, but not in the DP or in Dunning tumors. This suggests that a reduction in blood flow might be an important component for th e castration-induced involution and apoptosis in prostatic tissue. The reason why castration reduces blood flow only in the VP, and not in t he DP or Dunning tumor is unknown.