Hypoalaninemia and ketotic hypoglycemia: cause or consequence?

A shortage of alanine for gluconeogenesis is believed responsible for various forms of hypoglycemia and in particular ketotic hypoglycemia (KH). We examined the glucose-alanine relationship in two groups of fasting children, 18 with KH and 44 controls. Glucose levels declined in both groups but significantly more in KH; to 1.98 +/- 0.20 versus 3.26 +/-0.13 mM (mean +/- SEM; P less than 0.001). Alanine also fell in both groups, the concentrations correlating significantly with the concomitant glucose levels (KH: r = 0.64, P less than 0.001, and controls: r = 0.50, P less than 0.001). The relationship of alanine to glucose gave virtually identical regression equations, y = 0.054x + 0.063 for KH and y = 0.054x + 0.050 for controls. The differences in alanine levels between the two groups were too small to account for the greater decline in glucose in KH. The results indicate that hypoalaninemia rather than causing hypoglycemia results from it.