The role played by hormonal factors in the rapid activation of liver glycogen phosphorylase in traumatized rats.
In adult male SPF rats anaesthetized with pentobarbital and subjected to traumatization in revolving Noble-Collip drums for 2 min (= 120 revolutions) maximal increases of liver glycogen phosphorylase activity were observed. In experiments on rats with permanent arterial catheters for blood sampling no posttraumatic increase of plasma norepinephrine and an only slight increase of plasma epinephrine was observed if the animals were traumatized under anaesthesia, in contrast to the considerable increases in the plasma level of both hormones in rats subjected to the injury without anaesthesia. Time and extent of the phosphorylase response of anaesthetized rats after trauma were compared with changes in enzyme activity after i.v. administration of exogenous epinephrine or glucagon. A nearly maximal response after 1 microgram kg-1 epinephrine was present within 1 min, whereas after 0.1 micrograms kg-1 of glucagon there was comparable phosphorylase activation 2 min after administration of the hormone. The plasma renin-angiotensin activity was not increased after injury for 2 min under anaesthesia so that only the increase in plasma vasopressin fitted in with the criteria for possible activators of phosphorylase. An additional role of glucagon also cannot be excluded on the basis of data obtained by the present authors. The increase of phosphorylase activity in this type of stress is ensured by several mechanisms. Moreover, the high effectivity of these hormonal factors in evoking the phosphorylase response even without major activation of the sympathicoadrenal system is underlined.
D000758:Anesthesia; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D005934:Glucagon / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D006005:Phosphorylases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D014947:Wounds and Injuries / Q000097:blood / Q000201:enzymology*
D000804:Angiotensin II; D005934:Glucagon; D006005:Phosphorylases; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine