Abstract
Adrenergic regulation of prostaglandin (PG) biosynthesis was investigated in 1-14C-arachidonic acid-prelabeled cultured rabbit gastric epithelial cells (RGECs). RGECs expressed adrenergic α1-and β-receptors and muscarinic receptors. Norepinephrine facilitated the synthesis of PGs I2 (determined as the stable metabolite 6-keto PGF1α) and E2 and hydroxyfatty acids, while epinephrine facilitated the synthesis of PGI2 and hydroxyfatty acids, but not PGE2. However, isoproterenol did not affect PG biosynthesis. The effects of norepinephrine and epinephrine on PG biosynthesis were markedly suppressed by the non-selective α-blocker phentolamine and/or the selective α1-blocker prazosin. In combination with epinephrine, the selective α2-blocker yohimbine or the β-blocker propranolol facilitated PGE2 synthesis. Acetylcholine did not affect PG biosynthesis. These results indicate that norepinephrine and epinephrine act on PG biosynthesis as adrenergic agonists in these cultured RGECs and that an α1-receptor couples PGI2 and PGE2 synthesis.
