Bioavailability of starch and postprandial changes in splanchnic glucose metabolism in pigs

Changes in splanchnic metabolism in pigs were assessed after meals containi ng slowly or rapidly digested starch. The pigs were fed a mixed meal contai ning a "slow" native (n = 5) or a "rapid" pregelatinized (n = 5) cornstarch naturally enriched with [C-13]glucose. Absorption of [C-13]glucose was mon itored by the arteriovenous difference technique, and infusion of D-[6,6-H- 2(2)]glucose in the jugular vein was used to calculate the systemic appeara nce of [C-13]glucose. Arteriovenous balance data obtained during st 12-h st udy period showed that the fraction of ingested glucose equivalent appearin g as glucose in the portal vein was 49.7 +/- 7.2% for the slow starch and 4 8.2 +/- 7.5% for the rapid starch (P = 0.86). These values, corrected for t he gut extraction of circulating [C-13]glucose, became 66.4 +/- 5.6 and 65. 3 +/- 5.6%, respectively (P = 0.35). Isotope dilution data indicated that s ystemic appearance of exogenous [C-13]glucose represented 62.9 +/-. 7.6 and 67.4 +/- 3.0% of the oral load for slow and rapid starch, respectively (P = 0.68). Arterial glucose utilization by the gut increased from 7.3 +/- 0.9 mu mol.kg(-1).min(-1) before the meal to 8.5 +/- 1.6 mu mol.kg(-1).min(-1) during absorption, independently of the nature of the starch. Thus splanch nic glucose metabolism was unaffected by the nature of starch ingested.