Plasma prolactin responses to thyrotropin-releasing hormone in patients with breast cancer

Abstract

Plasma human prolactin levels were measured by homologous radioimmunoassay in patients with primary breast cancer and in normal women of similar age. In normal controls mean (.+-. standard error of the mean SEM) basal plasma prolactin levels were 11.9 .+-. 1.5 ng/ml and i.v. injection of synthetic thyrotropin-releasing hormone (TRH), 500 .mu.g, caused a significant rise in plasma prolactin in all subjects examined with a maximum response of 52.6 .+-. 3.3 ng/ml (mean .+-. SEM). Markedly high plasma prolactin levels and exaggerated plasma prolactin responses to TRH were demonstrated in some patients with breast cancer. Mean basal plasma prolactin levels and mean plasma prolactin increments following TRH in patients with breast cancer did not differ significantly from those in normal subjects. Plasma prolactin responses to TRH were slightly blunted during the administration of androgen in patients with breast cancer. Some of the patients with primary breast cancer probably have abnormal prolactin secretion.