Although many hormones exert tissue-specific effects through specific receptor interactions, the mineralocorticoid receptor in the renal collecting tubules
binds cortisol and aldosterone with equally high nanomolar affinity in vitro.
Severn DCTs merge to form a connecting tubule, which in turn, joins other collecting tubules
to conduct tubule fluid to a cortical collecting duct.
In the late distal tubule, the cell type responsible for [K.sup.+] transport is the late distal tubule cell, and in the cortical collecting tubule
, the cell type is the principal cell.
The tubular system has four components: (a) proximal tubule (PT), (b) loop of Henle, (c) distal tubule (DT), and (d) collecting tubule
. These components are divided further into subsegments each with specific cellular structures and functions.
Aldosterone mainly acts on the distal tubules and collecting tubules
The mechanism of ACE-I associated hyperkalaemia is mainly due to aldosterone deficiency with resultant decreased effect of aldosterone on collecting tubules
leading to reduced excretion of potassium and decreased sodium reabsorption [2, 3].
(11) One explanation has been found in immunocytochemical analyses of renal biopsies which have shown complete absence of H-ATPase pumps in the intercalated cell of the collecting tubules
which is largely responsible for proton secretion.
The ureteric bud divides and branches forming the renal pelvis, infundibulae, calyces, and collecting tubules
, which will provide a conduit for urine drainage in the mature kidney.
The cortical tubules mainly consisted of proximal and distal convoluted tubules together with collecting tubules
. Proximal convoluted tubules were lined by simple cuboidal epithelium with prominent brush border and distal convoluted tubules were lined by simple cuboidal epithelium with relatively larger lumen.
The frequency is reported as 0.2% to 0.3%.3-5 Risk factors were age, dilated collecting tubules
, horseshoe kidney, and retrorenal colon.