AJP - Renal Physiology, Vol 253, Issue 1 8-14, Copyright © 1987 by American Physiological Society
Response of collecting tubule cells to aldosterone and potassium loading
M. Kashgarian, T. Ardito, D. J. Hirsch and J. P. Hayslett
To investigate the sites of action of aldosterone (Aldo) and chronic
potassium loading (high K) and to determine whether dietary K can modulate
collecting duct structure independent of Aldo, a morphometric study of the
structure of the initial collecting tubule (ICT), the cortical collecting
tubule (CCT), the medullary collecting duct in the outer stripe (MCDOS) and
the inner stripe (MCDIS), and the papillary collecting duct (PCD) was
carried out in a rat model in which plasma levels of Aldo were clamped at
basal or physiologically elevated levels and high K could be induced
without concomitant hyperaldosteronism. Elevated levels of Aldo increased
cell area (Ac) and basolateral membrane surface (BLM) from control values
in the ICT, CCT, and MCDOS but not in the MCDIS or PCD. High K with normal
physiological levels of Aldo increased BLM in the ICT and CCT without a
concomitant change in AC. No response was seen in MCDOS, MCDIS, or PCD. It
is concluded that Aldo can modulate principal cell structure in the
collecting duct system in segments extending from the ICT through the MCDOS
in the rat and that high K independent of Aldo can influence collecting
duct structure only in the ICT and CCT.
