EFFECTS OF HEPATIC PORTAL INFUSION OF DEIONIZED WATER ON METABOLIC AND HORMONAL RESPONSES TO EXERCISE IN RATS

The present study was conducted to investigate the in vivo effects of an intrahepatic infusion of deionized water during exercise in rats. A drenodemedullated male Sprague-Dawley rats were continuously infused f or 30 min either at rest or during treadmill exercise (26 m/min, 0% gr ade). Rats were randomly assigned to one of three infusion conditions (52 mu l/min) with either deionized water (PW) or saline (PS; NaCl; 0. 9%) via the hepatic portal vein or deionized water through the jugular vein (JW). The exercise period caused a significant (P < 0.05) decrea se in liver glycogen and relative liver water content and peripheral a nd portal blood glucose and insulin while increasing peripheral and po rtal glucagon and K+ plasma concentrations. These responses, with the exception of K+, were not influenced by the different types of infusio ns. The increase in K+ during exercise was significantly (P < 0.05) hi gher in JW rats than in the PW and PS groups. Both the infusion and ex ercise protocols did not significantly alter the liver weight-to-body weight ratio, plasma osmolality, free fatty acids, beta-hydroxybutyrat e, Na+, Cl-, vasopressin, and catecholamine concentrations. It is conc luded that an hepatic portal infusion of deionized water does not spec ifically alter the metabolic and hormonal responses to exercise in rat s.