Low Dose Gossypol And L Gossypol For Male Antifertility Clinical Studies

The main side effect of gossypol used as a male contraceptive is hypokalemia. In order to avoid this side effect, we further reduced the daily loading dosage from 20 mg to 15 mg and 10 mg. and the maintenance dosage from 50 mg to 30 mg. 17 participants were divided into two groups. The first group of 6 participants took 15 mg per day for 60 days for loading, and 30 mg weekly for maintenance. The second group of 11 participants took 10 mg per day for loading and 30 mg for maintenance. Besides, there were two control groups with 8 and 10 participants respectively to match the two experiment groups.Follow-up was made every tow months including semen analysis, blood biochemistry and Beta-2-microgiobulin concentration in both serum and urine. In addition, we also adopted sperm-hamster egg penetration test for the purpose of getting a more accurate evaluation of sperm function. One year study showed the antifertility efficacy of the 15mg program was as good as the previous regular dose (20 mg) program, but that of the 10 mg program was not as good, with one case of failure-pregnancy. One year follow-up of blood and urine examinations were normal. Serum K in both 15 mg and 10 mg programs showed some declin in the summer season, but a similar decline was noted in the control groups. Hypo-kalemia was thought to be due to nephrotoxicity induced by gossypol , but in this study no significant change was demonstrated with the very sensitive Beta-2-MG renal function test. Result of this study shows that the change of serum K noted in this low dose program is probably due to weather but not gossypol. So lowering the dosage to a certain extent is very likely to be a feasible way to resolve the problem of gossypol's side reaction.