Effect of oral thyrotropin releasing hormone on serum prolactin, thyrotropin and total thyroxine levels in postpartum women.

A study was designed to investigate the effects of oral administration of thyrotropin releasing hormone (TRH) on prolactin levels and on thyroid function during the early puerperium. Eight lactating mothers took a single dose of oral TRH (40 mg) while eight other volunteers had a placebo treatment. Serial serum samples taken before and after treatment were assayed for prolactin, thyrotropin (TSH) and total thyroxine (T4) by using specific radioimmunoassays. There was approximately twofold increase in prolactin level at 30--210 min, about sevenfold increase in the TSH level at 210 min, and a marked increasing trend in the T4 level during the study period only in the treatment group. Six mothers treated with TRH and two treated with placebo regarded milk secretion more abundant in post-test than pre-test feeding. However, before TRH could be extensively tested on mothers with deficient lactation a thorough study of the effects of oral TRH on thyroid function in the puerperium is mandatory.