Submitted to: Metabolism
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2002
Publication Date: 7/1/2002
Citation: Sunehag AL, Haymond MW. Splanchnic Galactose Extraction is Regulated by Coingetstion of Glucose in Humans. 2002 Metabolism 51:827-832 Interpretive Summary: Our results demonstrate that during ingestion of galactose alone, splanchnic extraction of galactose is saturable at about 15 mmol/kg/min and that galactose becomes the major source of glucose production. In contrast, during co-ingestion of equal amounts of glucose and galactose, splanchnic extraction of galactose increases resulting in lower plasma concentration and appearance rates of galactose and reduced contribution from galactose to glucose despite the higher rate of splanchnic extraction of galactose.
Technical Abstract: When compared with galactose alone, coingestion of glucose with galactose decreases plasma galactose. The objective of this study was to determine if this was due to increased peripheral clearance or increased first pass clearance of galactose. Five adult volunteers were studied on 2 occasions during infusion of [6,6-(2)H(2)]glucose and [1-(13)C]galactose and ingestion of galactose alone at 11, 22, and 33 micromol x kg(-1) x min(-1) or galactose plus glucose at 11, 22, and 33 micromol x kg(-1) x min(-1) of each sugar. At 33 micromol x kg(-1) x min(-1) of galactose alone (1) plasma galactose increased to 2.3 +/- 0.3 mmol/L and galactose rates of appearance (Ra) to 18.3 +/- 1.6 micromol x kg(-1) x min(-1); (2) plasma glucose and glucose Ra were unaffected; (3) splanchnic extraction of galactose plateaued at approximately 15 micromol x kg(-1) x min(-1); and (4) galactose became the primary source of glucose Ra (75% +/- 9%). Coingestion of glucose and galactose at 33 micromol x kg(-1) x min(-1) each resulted in (1) decreased plasma galactose (0.3 +/- 0.1 mmol/L) and galactose Ra (6.4 +/- 1.8 micromol x kg(-1) x min(-1)); (2) increased plasma glucose and insulin; (3) doubling of splanchnic extraction of galactose; and (4) decreased contribution of galactose to glucose Ra (11% +/- 4%). We conclude that coingestion of glucose with galactose increases the splanchnic extraction, but decreases the conversion of galactose to glucose.