Direct action of androgen on hot flushes in the human male

Hot flushes (HF) were demonstrated definitively in a hypogonadal man by continuous recordings of finger temperature, skin resistance and subjective symptoms. The magnitudes and temporal interrelationships of these physiological changes were similar to those previously observed in oophorectomized women. HF were abolished by injections of methyl testosterone (MT) and during oral administration of fluoxymesterone (FM), a non-aromatizable androgen. Increases of the non-SHBG bound fractions of T and E2 were noted during MT therapy, either of which may have been responsible for suppression of HF. No significant changes of the non-SHBG bound levels of E2 were observed during FM ingestion. These data confirm that typical HF occur in the male and support the concept that androgen acts directly on the central nervous system without requiring aromatization to estrogen in the brain or other tissues.