The effects of glucose and alanine infusion on urea production and gluconeogenesis in the starved newborn guinea pig.

We studied the effects of glucose, alanine, and saline infusion in newborn guinea pigs. After acute (24-30 h after delivery) or prolonged (96-100 h after delivery) starvation, alanine or glucose infusion significantly increased liver glycogen concentration. Alanine infusion increased plasma glucose concentration and urea production rate (UrP). After acute starvation, a continuous 12-hour glucose infusion did not affect either plasma alanine concentration or UrP; however, after prolonged starvation, glucose infusion significantly reduced both variables. After prolonged starvation, the newborn guinea pig mobilizes alanine for gluconeogenesis. Increased protein catabolism is a consequence of this process. Glucose infusion negates the need for gluconeogenesis and spares body protein.