Factors affecting the permeability of isolated fat-cells from the rat to [42K] potassium and [36Cl] chloride ions.
1. The effluxes of (42)K(+) and (36)Cl(-) from isolated fat-cells from the rat were studied under a variety of conditions known to affect the metabolism of the cells. 2. (42)K(+) efflux from isolated fat cells was increased in a Na(+)-free-high-K(+) medium and decreased in a K(+)-free medium. The existence of K(+) exchange diffusion across the fat-cell membrane is suggested. 3. (36)Cl(-) efflux from isolated fat-cells was decreased when the Cl(-) component of the wash medium was replaced by acetate. The basal (36)Cl(-) efflux is suggested to be partly by Cl(-) exchange diffusion and partly in company with a univalent cation. 4. A variety of lipolytic stimuli, adrenaline, adrenocorticotrophic hormone, N-6,O-2'-dibutyryladenosine cyclic 3':5'-monophosphate and theophylline, increased (42)K(+) efflux from isolated fat-cells. The adrenaline stimulation was biphasic; an initial, rapid and transient increase in (42)K(+) loss from the fat-cells was followed by a slower, more prolonged, increase in (42)K(+) efflux. The initial phase was inhibited by phentolamine but not by propranolol. 5. Insulin increased (42)K(+) efflux only after preincubation with the cells.
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D002463:Cell Membrane Permeability; D002712:Chlorides / Q000378:metabolism*; D002713:Chlorine; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011194:Potassium Isotopes; D011433:Propranolol / Q000494:pharmacology; D011868:Radioisotopes; D051381:Rats; D013268:Stimulation, Chemical; D013806:Theophylline / Q000494:pharmacology
D002712:Chlorides; D007328:Insulin; D011194:Potassium Isotopes; D011868:Radioisotopes; D002713:Chlorine; D000324:Adrenocorticotropic Hormone; D011433:Propranolol; D013806:Theophylline; D011188:Potassium; D004837:Epinephrine; D010646:Phentolamine