Arginase - Role in Sexual Response

Role in Sexual Response

Arginase II is coexpressed with nitric oxide (NO) synthase in smooth muscle tissue, such as the muscle in the genitals of both men and women. The contraction and relaxation of these muscles has been attributed to NO synthase, which causes rapid relaxation of smooth muscle tissue and facilitates engorgement of tissue necessary for normal sexual response. However, since NO synthase and arginase compete for the same substrate (L-arginine), over-expressed arginase can affect NO synthase activity and NO-dependent smooth muscle relaxation by depleting the substrate pool of L-arginine that would otherwise be available to NO synthase. In contrast, inhibiting arginase with ABH or other boronic acid inhibitors will maintain normal cellular levels of arginine, thus allowing for normal muscle relaxation and sexual response.

Recent studies have implicated arginase as a controlling factor in both male erectile function and female sexual arousal, and is therefore a potential target for treatment of sexual dysfunction in both sexes. Additionally, supplementing the diet with additional L-arginine will decrease the amount of competition between arginase and NO synthase by providing extra substrate for each enzyme.