VIP and histamine H2 receptor activity in human fetal gastric glands

Vasoactive intestinal peptide (VIP, EC50 = 6.4 X 10(-10)M) and histamine (EC50 = 3 X 10(-6)M) activated the cyclic AMP generating system in gastric glands isolated from two human fetuses at 23 weeks gestation. Histamine antagonism by the H2 receptor blockers cimetidine (Ki = 0.35 X 10(-6)M) and ranitidine (ki = 0.51 X 10(-7)M) clearly characterized the histaminic activation as being of the H2 type. It is suggested that these two vasoactive hormones may operate as neurocrine/paracrine regulators of the differentiation and/or function of the human gastric mucosa in utero.