SOCIOSEXUAL BEHAVIOR AND PATERNITY IN PROCARBAZINE-EXPOSED RATS WITH OR WITHOUT REGIONAL TESTICULAR CIRCULATORY ISOLATION

Male Sprague-Dawley rats were used in two experiments in which a proca rbazine bolus (400 mg kg(-1) body mass) was administered with or witho ut testicular circulatory isolation in the form of brief clamping of t he spermatic cord and gubernaculum during drug administration. Separat e tests of aggressiveness, sexual motivation, copulatory performance a nd paternity over the subsequent 6 weeks were used to assess functiona l changes resulting from testicular circulatory isolation. Experiment I compared intermale aggression and sexual motivation of animals in gr oups receiving procarbazine plus testicular circulatory isolation last ing 0, 15 or 45 min with that of animals in control groups with no cla mp and no drug. Experiment 2 used a 2x2 factorial design to evaluate s exual performance and resulting paternity in animals 2 months after te sticular circulatory isolation and drug exposure compared with that in control animals. Procarbazine treatment induced minimal disruption of normal interest in a receptive female, copulatory measures (intromiss ions or ejaculations) and structural integrity of seminal vesicles, bu lbospongiosus muscles and ventral prostate glands. Animals exposed to the drug without testicular circulatory isolation were significantly l ess aggressive than animals in other groups. The most profound influen ce of procarbazine was on paternity. Males exposed to procarbazine wit h or without testicular circulatory isolation impregnated notably fewe r females than did control males that were not exposed to the drug. Th ere was no evidence of recovery of normal fertility up to 10 weeks aft er exposure to the drug. In conclusion, the deleterious influence of p rocarbazine on androgen-sensitive processes appears to be specific to intermale aggression and to fertility. The testicular circulatory isol ation technique, for 45 min in particular, softened the impact of the drug on social behaviour, although procarbazine suppressed fecundity e ven with testicular circulatory isolation.