Glucose Production and Utilization in the Newborn Puppy

Extract: A steady-state radioglyucose dilution technique was used to determine new glucose production in six newborn (1–4 days) and two adult dogs in the postabsorptive state, and during a 90-min glucagon infusion. Basal new glucose production rates were 2.0 and 2.2 mg/kg body weight per minute in the adults. In contrast, basal rates in the newborn were 2–4 times (4.1–7.9 mg/kg/min) the values for the adults. During glucagon-induced hyperglycemia in the adult, glucose production increased to 2.5 times the basal level, while plasma glucose concentration rose to a peak at 30 min. The newborn dog responded with only a 40% increment above basal production while glucose concentation rose continuously. The adult responded with a rise in plasma insulin level but no change was observed in the newborn. The fractional rate of glucose utilization during the glucagon-induced hyperglycemia was observed to decline in newborn dogs; no decline was observed in the adults. Glucose metabolism in the newborn differs from that in the adult dog as follows: 1) basal glucose production and utilization per unit body weight are rathter in the newborn; and 2) during glucagon-stimulated hyperglycemia the newborn adaps with less acceleration of both the production and the utilization of glucose. Speculation: If the human newborn responds similarly to the puppy, then hepatic glucose output appears to be near maximum in order to meet basal requirements for glucose. Conditions that accelerate peripheral tissue glucose uptake will, therefore, rapidly result in hypoglycemia. Conversely, a reduction in hepatic output may result in low blood glucose concentration.