[Micropuncture study of sodium chloride and bicarbonate reabsorption in the proximal tubule of the lamprey, Lampetra fluviatilis, kidney].

Proximal tubules of the kidney have been injected in vivo with isotonic solutions (in mequiv./1: 120 NaCl; 120.4 Na, 114.0 Cl, 6.4 HCO3 and 120 Na, 60 Cl, 60 HCO3) and half time (t 1/2) of fluid absorption was measured by shrinking drops technique. The value of t 1/2 was found to be significantly lower for NaCl solution than for NaCl--NaHCO3 (1:1) one. These data suggest that proximal reabsorption of chloride and bicarbonate is provided by separate specific transport systems.