The activity of the Na+-K+-pump is intricately linked to the maintenance of vascular tone. Here we demonstrate that insulin-like growth factor I (IGF-I) increases Na+-K+-pump activity in the vascular smooth muscle cell (VSMC) clone A7r5 in a time- and dose-dependent manner. This stimulatory effect of IGF-I was prevented by the tyrosine kinase inhibitor genistein (5 μM) and by the specific phosp...

ACTIVE REABSORPTION of Na across the thick ascending limb of Henle (TALH) plays an essential role in the urine concentrating mechanism, as it generates and maintains the axial osmolality gradient in the outer medulla. Na enters the TALH cell mostly through apical Na -K -2Cl (NKCC2) cotransporters, to a lesser extent through Na /H (NHE3) exchangers, and it is extruded at the basolateral membrane...

The sublingual salt gland is the primary site of salt excretion in sea snakes; however, little is known about the mechanisms mediating ion excretion. Na(+)/K(+)-ATPase (NKA) and Na(+)/K(+)/2Cl(-) cotransporter (NKCC) are two proteins known to regulate membrane potential and drive salt secretion in most vertebrate secretory cells. We hypothesized that NKA and NKCC would localize to the basolater...

Dietary potassium loading results in rapid kaliuresis, natriuresis, and diuresis associated with reduced phosphorylation (p) of the distal tubule Na(+)-Cl(-) cotransporter (NCC). Decreased NCC-p inhibits NCC-mediated Na(+) reabsorption and shifts Na(+) downstream for reabsorption by epithelial Na(+) channels (ENaC), which can drive K(+) secretion. Whether the signal is initiated by ingesting po...

The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 μM) had no effect on the transepithelial secretion of Na(+), K(+), Cl(-), and water. In contrast, 10 μM VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules we...