Figure 1.

Relative glucose production as a function of incubation time, by everted sleeves from the proximal region of the intestine of six mice. Sleeves were incubated at 37°C in Ringer’s solution containing 50 mM sucrose (by isosmotic replacement of NaCl), and sequential samples were drawn at 2, 4, 8, 12, 16, and 24 min and assayed for glucose produced by action of brush-border sucrase on the sucrose. Cumulative glucose production up to a given time was divided by production up to 12 min by the same sleeve, to account for individual variation among mice. Points are average values for the six mice, and bars denote standard errors (omitted if the bar is smaller than the size of the data symbol). Note the good fit (R² = 1.00) to a straight line passing close to the origin. Results for mid- and distal intestine give identically good fits (R² = 1.00) to very similar straight lines.