Differences in reproductive endocrinology between Asian men and Caucasian men - a literature review

This review provides an overview of the literature on aspects of reproducti ve endocrinology wherein Asian men may differ from Caucasian, notably, pros tatic nioplasm and the sensivity to pharmacological regimens of male contra ception. Both genetic and environmental factors, such as nutrition, might b e relevant. Asian men residing in Asia seem to be relatively protected from clinical prostatic nioplasm while the prevalence of preclinical prostatic nioplasm is not different. Migration to an area with a higher prevalence re duces this difference but does not undo it. With regard to prostatic niopla sm the following factors have been considered as relevant in Asian men: 1) a reduction in 5 alpha -reductase level, 2) decreased levels of androgenic ketosteroid precursors of 5 alpha -reduced androgen metabolites, 3) the dec reased presence of a P53 mutation, 4) a higher GAG-repeat length of the and rogen receptor, 5) a possible higher level of physical activity, 6) differe nces in sexual activity. Furthermore, Asian men respond to a higher degree with azoospermia in response to contraceptive steroids. Possible explanatio ns offered for the more pronounced response to contraceptive steroids are: 1) differences in testicular structure and decreased spermatogenic potentia l, 2) an earlier and more marked suppression in LH secretion by exogenous a ndrogens. The differences may be due to genetical and/or environmental fact ors influencing the peripheral testosterone metabolism. Dietary factors suc h as the higher intake of phytoestrogens in Asians might exert effects on S a-reductase activity and/or on sex hormone binding globulin (SHBG) levels, thus having an impact on the biological efficay of circulating androgens.