Effect of endogenous hyperprolactinemia on human lower esophagel sphincter pressure

The cause of gastroesophageal reflux occurring during pregnancy is not completely understood but may be related to changes in the hormonal environment specifically related to pregnancy. To evaluate the possible role of prolactin, one of the hormones elevated during pregnancy, we studied the effect of endogenously elevated serum prolactin concentrations, induced by I.V. thyrotropin-releasing hormone (TRH), on lower esophageal sphincter pressure (LESP) in normal subjects. Elevated prolactin concentrations (P less than 0.0001), did not change LESP over a 60-minute period. Serum gastrin concentration did not change significantly at any time during the study. We conclude: 1. acute elevations of serum prolactin comparable to the concentrations that occur during pregnancy did not change LESP; 2. there is no evidence that the hypothalamic regulating factor TRH affects serum gastrin concentration in man.