Localization of peptide YY (PYY) in gastrointestinal endocrine cells and effects on intestinal blood flow and motility.

Abstract

In immunohistochemical studies using antisera to peptide YY (PYY), a 36 amino acid polypeptide isolated from porcine duodenum, PYY-like immunoreactivity occurred mainly in endocrine cells of the gastrointestinal mucosa. PYY-immunoreactive cells were particularly abundant in the distal intestine and were observed in 5 species [rat, pig, cat, guinea pig and man]. By radioimmunoassay it was found that, in the rat, the amount of PYY immunoreactivity was .apprx. 100-fold higher in the colon than in the duodenum. The chromatographic profiles of PYY immunoreactivity from the rat colon and porcine PYY on a SP-Sephadex ion exchanger were simlar. Serial dilutions of extracts from the rat colon and porcine PYY had parallel displacement curves in radioimmunoassay. Close intraarterial administration of PYY in cats caused an intestinal vasoconstriction and an inhibition of jejunal and colonic motility. Simultaneously there was a rise in systemic arterial blood pressure. These effects of PYY were also observed after pretreatment with adrenergic blocking agents. PYY evidently is a gastrointestinal peptide that is present mainly in endocrine cells of distal intestine and has effects on both intestinal motility and the cardiovascular system.