Involvement of beta1- and beta2- but not beta3-adrenoceptor activation in adrenergic PYY secretion from the isolated colon
Journal of Endocrinology
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 -adrenergic agonist isoproterenol induce PYY secretion from rat isolated colon or ileum. Because 3-adrenergic receptors now appear to mediate many of the effects of catecholamines in the gastrointestinal tract, we investigated the involvement of 1-, 2-, and 3adrenoceptor stimulation in PYY secretion from the isolated,
... om 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<0·05), that was abolished by a previous infusion of the 1-and 2-adrenergic blocker (and partial 3-agonist) alprenolol (10 6 M). The 1-adrenergic agonist dobutamine and the -2 agonist terbutaline also (both at 10 5 M) significantly stimulated PYY secretion, from 29 1 to 79 12 fmol/2 min and from 19 1 to 73 13 fmol/ 2 min respectively (n=7, P<0·05). Neither of the 3adrenergic agonists tested (BRL 37 344 (10 5 , 10 6 M) and SR 58 611A (10 6 M)) significantly stimulated PYY secretion, thus confirming the exclusive involvement of 1-and 2-receptors in -adrenergic agonist induced hormone secretion.