Independent modulation by food supply of two distinct sodium-activated D-glucose transport systems in the guinea pig jejunal brush-border membrane

Proc Natl Acad Sci U S A. 1988 Sep;85(17):6370-3. doi: 10.1073/pnas.85.17.6370.


D-glucose transport across the intestinal brush-border membrane involves two transport systems designated here as systems 1 and 2. Kinetic properties for both D-glucose and methyl alpha-D-glucopyranoside transport were measured at 35 degrees C by using brush-border membrane vesicles prepared from either control, fasted (48 hr), or semistarved (10 days) animals. The results show the following: (i) The sugar influx rate by simple diffusion was identical under either altered condition. (ii) Semistarvation stimulated D-glucose uptake by system 2 (both its Vmax and Km increased), whereas system 1 was untouched. (iii) Fasting increased the capacity of system 1 without affecting either Km of system 1 or Vmax and Km of system 2. The effect of fasting on Vmax of system 1 cannot be attributed to indirect effects from changes in ionic permeability because the kinetic difference between control and fasted animals persisted when the membrane potential was short-circuited with equilibrated K+ and valinomycin. This work provides further evidence for the existence of two distinct sodium-activated D-glucose transport systems in the intestinal brush-border membrane, which adapt independently to either semistarvation or fasting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diet*
  • Eating
  • Female
  • Glucose / metabolism
  • Guinea Pigs
  • Jejunum / metabolism*
  • Kinetics
  • Microvilli / drug effects
  • Microvilli / metabolism*
  • Monosaccharide Transport Proteins / metabolism*
  • Sodium / pharmacology*
  • Starvation


  • Monosaccharide Transport Proteins
  • Sodium
  • Glucose