Effect of oral alanine on blood beta-hydroxybutyrate and plasma glucose, insulin, free fatty acids, and growth hormone in normal and diabetic subjects

Abstract

Blood beta-hydroxybutyrate and plasma free fatty acids, glucose, insulin, and growth hormone responses were measured following oral 1-alanine in doses of 0.5 or 0.1 g/kg. In normal and untreated adult diabetic subjects beta-hydroxybutyrate decreased 59%–84% (high dose) and 34%–47% (low dose). This reduction occurred in two phases, the first corresponding to a rise in plasma insulin (high and low dose) and the second corresponding to a fall in free fatty acids (with high dose only). In long-term insulin-treated diabetics made ketotic by withdrawal of insulin, the first phase was still clearly demonstrable, suggesting that alanine is capable of inhibiting ketosis by some extrainsulin mechanism. In these subjects, alanine produced a rise in free fatty acids as beta-hydroxybutyrate fell. Plasma glucose remained stable in normal and untreated diabetics, but rose significantly in insulin-dependent diabetics. Alanine also produced a delayed release of growth hormone starting at 90 min in normals and insulin-dependent diabetics. This release appeared to correlate with and was likely due to a preceding fall in free fatty acids.