Plasma testosterone and the diagnosis of panhypopituitarism in women.

Plasma testosterone was shown to be a very sensitive index of panhypopituitarism in women. In 18 women, testosterone levels were found to be 0.06 +/- 0.04 ng/ml (mean +/- SD; normal, 0.40 +/- 0.10 ng/ml). In all patients, the values were below 2 SD of testosterone levels found in normal women. Dihydrotestosterone concentrations were similarly modified. Such an important decrease in plasma testosterone was probably due to the additional effect produced by the functional suppression of both sources of testosterone precursors: the adrenals and the ovaries.