Potassium transport in cortical collecting tubules from mineralocorticoid-treated rat

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · Am. J. Physiol.; (United States)

OSTI ID:6244481

Schafer, J A; Troutman, S L

Unidirectional fluxes of /sup 86/Rb/sup +/ were used to examine the stimulation of K/sup +/ secretion produced by arginine vasopressin (ADH) in isolated perfused cortical collecting tubules from rats treated with desoxycorticosterone. ADH at 100 ..mu..U/ml in the bathing solution increased the bath-to-lumen flux (J/sub b..-->..1/; pmol /center dot/ min/sup -1/ /center dot/ mm/sup -1/) from 16.9 /plus minus/ 2.3 to 43.2 /plus minus/ 4.6. The lumen-to-bath flux (J/sub 1..-->..b/) fell from 3.2 /plus minus/ 0.7 to 1.3 /plus minus/ 0.4 with ADH due to hyperpolarization of the transepithelial voltage from -12.6 /plus minus/ 1.3 to /minus/39.3 /plus minus/ 2.0 mV, but the calculated Rb/sup +/ permeability was unaltered at 0.20-0.26 ..mu..m/s. Although 2 mM lumen Ba/sup 2 +/ inhibited J/sub b..-->..1/ by 55 /plus minus/ 6%, the flux ratio (J/sub b..-->..1//J/sub 1..-->..b/) of 28 /plus minus/ 8 was larger than predicted for passive exchange. In the absence of ADH 2 mM Ba/sup 2 +/ reduced J/sub b..-->..1/ to the level predicted for passive movement, but addition of ADH with Ba/sup 2 +/ still present increased J/sub 1..-->..1/ by an amount identical to that observed without Ba/sup 2 +/, although the absolute J/sub b..-->..1/ was less. Simultaneous addition of 2 mM luminal and 4 mM bath Ba/sup 2 +/ also inhibited J/sub 1..-->..b/ for /sup 22/Na/sup +/ but not to passive levels. These results indicate either that the concentrations of Ba/sup 2 +/ used were insufficient to block K/sup +/ conductances completely or that K/sup +//Rb/sup +/ secretion can occur through a Ba/sup 2 +/-insensitive pathway.

• Research Organization: Univ. of Alabama, Birmingham (USA)
• OSTI ID: 6244481
• Journal Information: Am. J. Physiol.; (United States), Vol. 253:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CATIONS
SECRETION
RUBIDIUM 86
UPTAKE
TUBULES
PHYSIOLOGY
BIOELECTRICITY
INULIN
POTASSIUM CHLORIDES
SODIUM COMPOUNDS
TRITIUM COMPOUNDS
VASOPRESSIN
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
ELECTRICITY
HALIDES
HALOGEN COMPOUNDS
HORMONES
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KIDNEYS
LABELLED COMPOUNDS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
POLYSACCHARIDES
POTASSIUM COMPOUNDS
RADIOISOTOPES
RUBIDIUM ISOTOPES
SACCHARIDES
550201* - Biochemistry- Tracer Techniques