Alpha and beta adrenoceptors mediate the inhibitory effect of epinephrine on the mucosal uptake of phenylalanine in the rat jejunum

Abstract

Although adrenergic agonists and antagonists have extensive clinical use, their effects on the intestinal absorption of amino acids have rarely been investigated. This work attempts to study the effect of epinephrine on the mucosal uptake of phenylalanine in the rat jejunum, using an in situ double perfusion technique that allows the intestine and its vasculature to be perfused simultaneously and respectively with the amino acid and the hormone and its antagonists. Epinephrine reduced, by about 30%, the mucosal transport of phenylalanine by activating alpha 1, alpha 2, and beta adrenergic receptors. The effect of the latter was not apparent however, until the alpha 2 receptors were blocked.