Action of phlorizin on luminal and antiluminal membranes of proximal cells of kidney.
In accord with results of others, we have observed that the infusion of phlorizin at low rates (2.16-117 microgram-kg-1-min-1) progressively increases fractional excretion of glucose from 0.47 to 0.85. Further increasing the rate of infusion to 2.19 mg-kg-1-min-1 increases fractional excretion to 1.0. The relationship appears to describe a single function having characteristics of an adsorption isotherm. The metabolism of the kidney, expressed as rate of total CO2 production from all substrates, is modestly and variably reduced by infusion of phlorizin at both high and low rates. The metabolism of glucose, expressed as rate of CO2 production, is variably but not consistently altered by infusion of phlorizin. The oxidation of [14C]lactate derived from [14C]glucose is negligible and introduces no significant error into measurement of 14CO2 from [14C]glucose. The percent of total CO2 derived from glucose does not differe significantly in control periods from the mean of all periods following phlorizin. Accordingly interaction of phlorizin with peritubular membranes at high rates of infusion, in the sense of blocking penetration of glucose, does not occur. Our methods do not rule out nor do they prove adsorption of phlorizin to these membranes.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D004285:Dogs; D005947:Glucose / Q000378:metabolism; D007263:Infusions, Parenteral; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D010695:Phlorhizin / Q000008:administration & dosage / Q000494:pharmacology*
D010695:Phlorhizin; D005947:Glucose