Involvement of beta1- and beta2- but not beta3-adrenoceptor activation in adrenergic PYY secretion from the isolated colon

The secretion of PYY by endocrine L cells of the terminal gut is under the control of nutrients, the autonomic nervous system and hormones. Catecholamines, and the non-specific beta-adrenergic agonist isoproterenol induce PYY secretion from rat isolated colon or ileum. Because beta3-adrenergic receptors now appear to mediate many of the effects of catecholamines in the gastrointestinal tract, we investigated the involvement of beta1-, beta2-, and beta3-adrenoceptor stimulation in PYY secretion from the isolated, vascularly perfused rat colon. Infusion of 10(-6) M isoproterenol induced a transient increase in PYY secretion (from 36+/-4 to 87+/-20 fmol/2 min; n=7, P