Evidence for increased permeability of rat liver plasma membrane vesicles after CCl/sub 4/ in vivo
Plasma membrane vesicles (PMs) of CCl/sub 4/-dosed rats show nearly total loss of ATP-driven Ca2+ uptake, more than produced by acetaminophen or bromobenzene. The authors postulated that CCl/sub 4/ PMs are more permeable or have less Ca2+ binding capacity and now report studies to test these hypotheses. After passive loading in 1 mM Ca2+, biphasic Ca2+ efflux was much more rapid in CCl/sub 4/ PMs; kefflux = 0.272 and 0.0516 min-1 for control, and 1.78 and 0.171 min-1 for CCl/sub 4/, based on semilog plots of averaged efflux data (N = 6). CCl/sub 4/ PMs lost 81% of zero time Ca2+ (corrected for Ca2+ not releasable by A23187) in 5 min, while controls lost 45%. /sup 86/Rb+ uptake in the presence of valinomycin measured the ability of PMs to maintain a K+ gradient when 100 mM KCl-loaded PMs were stripped of external K+. CCl/sub 4/ PMs took up half as much /sup 86/Rb+, suggesting the K+ gradient was half that maintained by controls (N =3). Ca content of CCl/sub 4/ PMs was decreased: zero time (12.3 +/- 0.8 vs 8.3 +/- 0.8 nmols/mg; p < .01) and post-A23187 (3.3 +/- 0.3 vs 1.6 +/- 0.3 nmols/mg; p<.01) and post-A23187 (3.3 +/- 0.3 nmols/mg; p < .005) Ca2+ content were less in CCl/sub 4/ PMs in passive loading/efflux studies. Total Ca in CCl/sub 4/ PMs, by atomic absorption, was 10.9 +/- 1.2 vs 17.4 +/- 2.0 nmols/mg in controls; p < .025. Inhibition of the Ca2+ pump cannot be ruled out, but it seems clear that membrane structural changes influencing permeability occur after CCl/sub 4/ administration.
- Research Organization:
- Baylor College of Medicine, Houston, TX
- OSTI ID:
- 5316461
- Report Number(s):
- CONF-8604222-; TRN: 86-028579
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
CALCIUM
MEMBRANE TRANSPORT
CARBON TETRACHLORIDE
BIOLOGICAL EFFECTS
CELL MEMBRANES
PERMEABILITY
IN VIVO
LIVER
RATS
RUBIDIUM 86
TRACER TECHNIQUES
VALINOMYCIN
ALKALI METAL ISOTOPES
ALKALINE EARTH METALS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHLORINATED ALIPHATIC HYDROCARBONS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ELEMENTS
GLANDS
HALOGENATED ALIPHATIC HYDROCARBONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANS
RADIOISOTOPES
RODENTS
RUBIDIUM ISOTOPES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550201 - Biochemistry- Tracer Techniques