In vitro response of ATPase activities in tissue subcellular particle preparations to a series of mono-unsaturated C18 fatty acids.
The positions of the double bond and the cis/trans configurations of six mono-unsaturated C18 fatty acids (FA) showed selectivity for inhibition and stimulation of ATPase activities of tissue homogenate fractions. The 13,000 g and 100,000 g sediments (fractions B and C respectively) of tissues homogenates were used as sources of Na+-K+ ATPase and of oligomycin-sensitive (OS) and -insensitive (OIS) Mg2+ ATPase activities. Tissue source included bovine brain and rat brain, kidney, heart and liver. Cis mono-unsaturated C18 FA caused an apparent uncoupling of mitochondrial coupling factor F1 (Mg2+ ATPase). This was indicated by the loss of oligomycin and 1,1,1-trichloro-2,2 bis (p-chlorophenyl) ethane (DDT) sensitivity in the presence of 50 microM FA (12-C18:1). Thus, a precipitous decrease in OS-Mg2+ AtPase activity of mitochondria was accompanied by an equally steep increase in OIS-Mg2+ ATPase activity. This was especially apparent in the heart tissue preparation. The uncoupling action of the FA was not observed with the trans mono-unsaturated C18 FA, Na+-K+ ATPase activity from a bovine brain nerve ending particle (B) fraction was also sensitive to 12-C18:1 FA. However, inhibitory response of Na+-K+ ATPase activity were different for OS-Mg2+ ATPase activity. The latter (OS) was not sensitive to the trans 12-C18:1, while the former (Na+-K+) was sensitive to both cis and trans forms of 12-C18:1 and inhibition appeared to be dependent on the position of the double bond.
D000251:Adenosine Triphosphatases / Q000032:analysis*; D000818:Animals; D001921:Brain / Q000201:enzymology; D002417:Cattle; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D066298:In Vitro Techniques; D007668:Kidney / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D009840:Oligomycins / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship; D014475:Uncoupling Agents / Q000494:pharmacology
D005231:Fatty Acids, Unsaturated; D009840:Oligomycins; D014475:Uncoupling Agents; D000251:Adenosine Triphosphatases