Vasoactive intestinal polypeptide loses its ability to increase vaginal blood flow after menopause

In women who are fertile and not pregnant, vasoactive intestinal polypeptide (VIP) increases vaginal blood flow and lubrication to levels observed during sexual arousal. The effects of VIP were investigated in postmenopausal women by studying six women (average age, 58) who took no medication and six women (aged 54) who took hormonal replacement therapy for menopausal symptoms. Vaginal blood flow was measured by a heated probe placed in the vagina before and after an intravenous infusion of VIP. Blood was sampled at regular intervals to determine VIP concentrations. Results showed that the drug did not increase vaginal blood flow for women who did not take hormones, but it did increase blood flow for women on hormone replacements. The women had similar increases in their blood VIP levels. It appears that the vaginal effects of VIP are dependent on the presence of sex hormones. Additional research is needed to characterize the physiological aspects of these mechanisms. (Consumer Summary produced by Reliance Medical Information, Inc.)