Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1989 May;256(5 Pt 2):F932-41.
doi: 10.1152/ajprenal.1989.256.5.F932.

Flow dependence of K+ secretion in cortical distal tubules of the rat

Affiliations

Flow dependence of K+ secretion in cortical distal tubules of the rat

G Malnic et al. Am J Physiol. 1989 May.

Abstract

Superficial distal tubules were pump perfused (range 0-35 nl/min), generally with solutions similar in composition to early distal tubule fluid, in control, K+-depleted, acutely K+-loaded, and K+-adapted rats with the use of double-barreled resin-reference microelectrodes to measure K+ and Na+ activities and transepithelial potential differences (PD). When perfusion rate decreased from 35 to 5 nl/min in control animals, [K+] increased from 2 mM to between 10 and 20 mM, remaining at these levels as perfusion rate was decreased further. In low-K+ rats, the change in K+ activity with flow was greatly attenuated. In K+-loaded and K+-adapted rats, [K+] was higher than in controls at all flow rates. Na+ concentrations and lumen-negative PD increased with high flow rates in control rats. Addition of 10(-3) M amiloride blocked the increase in luminal K+ with low flow rates. In the physiological range of late distal flow rates, luminal [K+] remains constant and similar to the concentration attained in the steady state. At higher flow rates, [K+] declines, and K+ balance, PD, and Na+ reabsorption modulate the relationship between K+ secretion and flow rate.

PubMed Disclaimer

Publication types

LinkOut - more resources