Magnitude of ouabain-sensitive respiration in the liver of growing, lactating and starved sheep.

Oxygen consumption and ouabain-sensitive respiration was measured for liver biopsies from lactating and non-lactating ewes and for hepatocytes isolated from mature, dry ewes. O2 consumption, ouabain-sensitive respiration and 86Rb+ uptake were also measured for hepatocytes isolated from lambs, fed adult sheep and adult sheep starved for 5 d. Ouabain-sensitive respiration in the liver of ewes at peak lactation accounted for 45% of the total liver O2 consumption. This percentage was 24-37% higher (P less than 0.05) than measurements made during late lactation and during the non-lactating period. Total O2 consumption and ouabain-sensitive respiration rates of lamb hepatocytes were greater (P less than 0.05) than similar measurements for hepatocytes isolated from adult sheep. Ouabain-sensitive 86Rb+ uptake by hepatocytes from fed sheep was up to six times greater (P less than 0.05) than that by cells from starved sheep. The magnitude of ouabain-sensitive respiration of hepatocytes from starved sheep was 62% lower (P less than 0.05) than that for hepatocytes from fed sheep.