Interaction of Ingested Leucine with Glycine on Insulin and Glucose Concentrations

Table 1

Comparison of effects of single and two amino acids on glucose, insulin, and glucagon area responses.

Amino acid + glucose data
	Glucose		Insulin		Glucagon
	Area	%↓	Area	%↑	Area	%↑
Glycine publication*
Glucose	100%		100%		N/A^∧
Glucose + Gly	38%	62%	101%	1%
Leucine publication**
Glucose	100%		100%		−100%
Glucose + Leu	43%	57%	159%	59%	−7%	93%
Present publication***
Glucose	100%		100%		−100%
Gluc + Leu + Gly	34%	66%	124%	24%	−6%	94%
Individual amino acid data
	Glucose area		Insulin area		Glucagon area^∧∧
Glycine alone*	−3%		16%		N/A^∧
Leucine alone**	11%		10%		84%
Leu + Gly***	−9%		10%		67%

∗Gannon et al., 2002 [3].
∗∗Kalogeropoulou et al., 2008 [2].
∗∗∗Iverson et al., present paper.
The area response after ingestion of water only (control) was subtracted from the area response to the ingested test substances. All data are presented relative to the response to ingested glucose, which is set at +100% for glucose and insulin, and−100% for glucagon (because glucose ingestion results in a decrease in glucagon concentration).
^∧N/A: not applicable: The glucagon data published in the glycine paper were obtained using an older assay and cannot be quantitatively compared to the data from the leucine paper or the present leucine + glycine paper.
^∧∧Glucagon area when glucose alone is −100%.