Stimulation of Glucose Production by Hypoxia in Newborn Dogs

Abstract

The aim of the experiments was to examine the role of hypoxia as a possible regulator of hepatic glucose production in newborn dogs. In pups 1–30 days of age the rate of endogenous (hepatic) glucose production increased when the animals were ventilated with a gas mixture containing 10% or 5% O2. During a single 45 min exposure to hypoxia the increase in glucose production was significantly correlated with the O2 saturation in arterial blood. A second exposure to the more severe hypoxia (5% O2) following the first (10% O2) led to a second increase in the concentration of glucose in plasma and in glucose production. In pups less than 10 days of age, the increases during the second hypoxic period were only transient. During a 60 min rest following exposure to the more severe hypoxia (5% O2) basal glucose production rates and plasma concentrations were not reestablished. The metabolic clearance rate of glucose was not changed by hypoxia. There was a significant drop in plasma free fatty acid level. The increase in endogenous glucose production to hypoxia in pups indicates that the liver in the newborn animal is capable of increasing the rate of glucose production and that the known lack of a response to hypoglycemia is due to the absence of the feedback between glucose production and extracellular glucose concentration.