AJP - Renal Physiology, Vol 238, Issue 3 159-F165, Copyright © 1980 by American Physiological Society
Renal handling of phenol red. IV. Tubular localization in rabbit and rat kidney in vivo
M. I. Sheikh and J. V. Moller
In the rabbit kidney accumulation of phenol red in cortex tissue is
directly related to phenol red excretion. In histological preparations of
rabbit cortex the major part of phenol red is localized to the pars recta
of proximal tubules at low plasma concentrations of dye. The extra uptake
of dye by the pars recta is abolished by administration of a high dose of
probenecid and also by high plasma dye concentrations, when dye secretion
is low relative to tubular reabsorption. Tissue accumulation of phenol red
in the rat exhibits features similar to those in the rabbit. However, extra
dye uptake in the pars recta is maintained after administration of
probenecid, and disappears after intravenous injection of phenol red during
ureteral occlusion to impede access of dye from tubule fluid to the luminal
membrane. It is concluded that in the rabbit phenol red uptake by the pars
recta probably is due to tubular secretion across the peritubular membrane,
whereas in the rat extra uptake of dye by this segment is consistent with
uptake at the luminal cell membrane.
