Volume regulation initiated by Na+-nutrient cotransport in isolated mammalian villus enterocytes

tion initiated by N&nutrient cotransport in isolated mamma-lian uillus enterocytes. Am. J. Physiol. 260 (Gastrointest. Liver Physiol. 23): G26-G33, 1991.-We assessed ion transport dur-ing regulatory volume decrease (RVD) in jejunal villus entero-cytes, isolated in suspension from guinea pig jejunum and swollen by exposure to L-alanine (L-Ala) or D-glucose (D-Glc) in the presence of Na’. Cell volume was measured electroni-cally. Relative volume of cells (rel vol: cell vol/isotonic vol) within 1 min of L-Ala (20 mM) addition increased (1.10 k 0.03, P < 0.005), but by 5 min there was no difference between cells in L-Ala or 20 mM D-Ala (0.95 t 0.02). Cell shrinkage after maximal swelling was greater with L-Ala than with D-Ala (14 & 4 vs. 2 t l%, P < 0.01). Initial swelling generated by L-Ala required extracellular Na ’ (P < 0.02). Volume increased 30 s after D-Glc (20 mM), and cells were larger than cells treate