Platelet Adenylate Cyclase and Monoamine Oxidase in Women with Alcoholism or a Family History of Alcoholism

&NA; Purpose. Characteristic changes of platelet membrane monoamine oxidase and adenylate cyclase activities have been described in men with alcoholism. We studied the occurrence of these changes in abstinent alcoholic women and in nonalcoholic female control subjects with and without family histories of alcoholism. Methods. Blood samples were collected from 23 female alcoholics and 39 nonalcoholic female social drinkers. Platelet membrane assays were performed for monoamine oxidase and adenylate cyclase activities. Results. Alcoholic women had lower basal adenylate cyclase (p < 0.01) and adenylate cyclase activities stimulated by cesium fluoride (p < 0.001), by the guanine nucleotide analog 5‐guanylylimidodiphosphate (p < 0.02), and by prostaglandin E1 (p < 0.01). Female control subjects with family histories of alcoholism also had lower basal adenylate cyclase (p < 0.01) and adenylate cyclase activities enhanced by incubation with cesium fluoride (p < 0.005) and 5′‐guanylylimidodiphosphate (p < 0.001). Monoamine oxidase activity levels measured with (p < 0.001) and without ethanol (p < 0.01) were higher for alcoholic women. No significant differences were found between female control subjects with and without family histories of alcoholism for monoamine oxidase in the absence or presence of ethanol. Discussion. In vitro platelet adenylate cyclase activity may facilitate a diagnosis of alcoholism in women and may be a biologic indicator of vulnerability in the offspring of alcoholics.