Gossypol — Proposed Contraceptive for Men Passes the Ames Test

Abstract

Scientists from China recently reported that the administration of gossypol acetate or gossypol formate to men by mouth at a daily dosage of 20 mg caused sperm counts to drop to contraceptive levels. Monthly maintenance dosages of 150 to 220 mg were sufficient for contraceptive effectiveness in 99.89% of the 4000 men tested. If approved for general use in China the proposed contraceptive dosage would be about 3 g per man per year. The mode of action of gossypol a phenol extracted from the roots stems and seeds of the cotton plant is still under investigation. It is apparent however that gossypol does not act by alteration of serum hormone levels and its contraceptive effect is reversible. Side effects for some men were transient nausea reduced levels of potassium and inability to perspire but the relation of these symptoms to gossypol intake has not yet been firmly established. Although much information is available on the acute toxicity of gossypol systematic screening for possible mutagenic carcinogenic or teratogenic effects in standard bioassays has not yet been reported. However the authors have tested gossypol in the Ames salmonella-microsome test in 2 separate assays which have indicated that gossypol is not mutagenic to the 5 standard tester strains of S. typhimurium either with or without inclusion of a rat-liver metabolic-enzyme fraction. Nevertheless other tests on the chronic effects of gossypol may be warranted in view of the fact that it is a lipid-soluble compound and its retention time in the body is prolonged. High tissue concentrations may be reached.