The Effects of Abrupt Altitude Exposure (4300 m) upon the Metabolism of Glucose-14C-UL in Man,

Abstract : The catabolism of infused C14-glucose in sea level natives was compared during initial altitude exposure and at sea level. An increased disappearance of plasma radioactive glucose in two studies and an increased production of C140(2) in the second study were observed. Fasting plasma glucose levels decreased with increased duration of altitude exposure. Altitude exposure enhanced glucagon-mediated hyperglycemia. A shorter duration of hyperglycemia and reduced glucose levels after glucagon would suggest a depletion of liver glycogen stores in the 40-hour exposed men. Plasma levels of growth hormone were increased 6-10 fold during the first four hours at 4,300 meters. Insulin levels were increased after glucagon infusion in both altitude-exposed men and control men concomitant with increased plasma glucose values although the increases were not significantly correlated. These data indicate that glucose catabolism was enhanced during initial altitude exposure with an increased requirement for carbohydrates. (Author)