The vasodilator actions of isoprenaline, histamine, prostaglandin E2, glucagon and secretin on the hepatic arterial vascular bed of the dog.
The sympathetically-innervated arterial vascular bed of the dog's liver was perfused from a femoral artery. Arterial blood flow and perfusion pressure were measured continuously, and the hepatic arterial vascular resistance calculated. The preparation provided a means of assessing hepatic arterial vasodilatation quantitatively. 2 Isoprenaline, histamine, prostaglandin E2, glucagon and secretin were injected intra-arterially and all evoked dose-dependent vasodilatation of the hepatic arterial vascular bed. 3 The maximum reduction in the calculated hepatic arterial vascular resistance of 37-38% was the same for each of the five substances. 4 Comparisons on a weight basis revealed that prostaglandin E2 was the most potent, followed in potency order by secretin, isoprenaline, histamine and glucagon. 5 Comparisons on a molar basis showed that secretin and prostaglandin E3 were intrinsically considerably more potent than isoprenaline, histamine or glucagon. 6 The onset of the vasodilatator responses to secretin, isoprenaline, histamine and prostaglandin E2, was rapid, and the duration of their actions was brief. 7 The onset of the vasodilator effects of glucagon was slow and its duration of action very prolonged. 8 The implications of these observations with respect to the physiological control of the hepatic arterial vascular bed of the dog are discussed.
D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005934:Glucagon / Q000494:pharmacology*; D006499:Hepatic Artery / Q000187:drug effects*; D006632:Histamine / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008102:Liver Circulation / Q000187:drug effects; D011458:Prostaglandins E / Q000494:pharmacology*; D012633:Secretin / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents
D011458:Prostaglandins E; D014665:Vasodilator Agents; D012633:Secretin; D006632:Histamine; D005934:Glucagon; D007545:Isoproterenol