The present study reports the plasma levels of gonadotropins (luteinizing hormone, follicle-stimulating hormone), proopiomelanocortin-related peptides (adrenocorticotropic hormone, beta-endorphin, and beta-lipotropin), and cortisol in eight menopausal women experiencing frequent hot flushes. beta-Endorphin and beta-lipotropin levels were measured by radioimmunoassay after extraction and Sephadex G-75 column chromatography. Plasma levels of adrenocorticotropic hormone (after extraction), luteinizing hormone, follicle-stimulating hormone, and cortisol were measured by specific radioimmunoassay. All hormone levels showed a prompt and significant rise on occurrence of hot flushes (18 total recordings), remained high for 15 minutes, and decreased to basal levels 35 minutes later. The evaluation of the behavior pattern of single hormone levels revealed a more pronounced increase of proopiomelanocortin-related peptides and cortisol than of gonadotropins (p less than 0.01).