Item

Abstract

The transtubular net flux of glucose in the proximal tubule of rat kidney has been described as an active component (6, 7) which could be blocked by adding 1 x 10^–4M phlorizin to the perfusion solution and a diffusion component (7). The calculated apparent transport parameters were:
V_{max D − gl.} equal to 6 × 10⁻¹⁰ mol × cm⁻² × cm⁻¹.
K_{T D − gl.} equal to 0.6 × 10⁻³ M.
P_{D − gl.} equal to 1.7 × 10⁻⁵cm × sec⁻¹.
These microperfusion experiments were performed under the condition of zero net flux of water and electrolytes (sodium concentration 110 mEq). Under the condition of normal net flux of water and electrolytes (sodium concentration 145 mEq), the above-mentioned apparent transport parameters were in good agreement with those calculated from the measured intraluminal glucose concentration in the second part of the proximal tubule under free flow conditions.