Luminal and plasma glucose concentrations on intestinal fluid absorption and lymph flow.

The effect of luminal (GL) and plasma (GP) glucose concentration on intestinal fluid absorption and lymph flow in the rat was studied. When GL was zero, fluid absorption rate (JV), total lymph flow, and "excess lymph flow" (JLe) during absorption from Krebs-Ringer solution was 155 +/- 16, 30 +/- 4, and 11 +/- 4 microliters X cm-1 X h-1, respectively, and JLe accounted for 7% of JV. JLe was the difference between total lymph flow and basal (nonabsorptive) lymph flow (JLb). In the presence of 28 mM glucose, JV and JLe increased by 37% to 212 +/- 22 and by 318% to 46 +/- 6 microliter X cm-1 X h-1, respectively. There was no further increase of either parameter when GL was 56 or 100 mM. When GL was zero and GP was increased to 43-64 mM during intravenous infusion of hypertonic glucose solution (2.78 M), JV and JLe increased by 32-35 and 313-380%, respectively, compared with that when GP was normal (11-14 mM). When GL was 28 mM and GP was 56 mM, a maximal rate of JV and JLe was obtained, and JLe accounted for 43 +/- 7% of JV. During infusion of hypertonic NaCl solution (1.54 M), JV decreased with little change in JLe. Furthermore, during infusion of either NaCl or glucose solution, the increase of plasma osmolarity resulted in approximately 100% increase of JLb. The results demonstrate that either GL, or GP, or both, increased JV and especially increased JLe.(ABSTRACT TRUNCATED AT 250 WORDS)