Effects of Fasting and Hypophysectomy on FFA Uptake and Ketone Body Production by the Isolated, Perfused Rat Liver Free

The effect of fasting overnight and hypophysectomy on free fatty acid (FFA) uptake and ketone body production by isolated, perfused rat livers was investigated. FFA uptake was directly related to FFA concentration over a wide range of concentrations (0.31 to 2.41 mM) in both fed and fasted rats. Whereas ketone body production increased with FFA uptake, it was greater at any given FFA concentration in livers from overnight fasted than in livers from fed donors. The relationship between FFA concentration and FFA uptake was unaltered by hypophysectomy. At low FFA concentrations livers from fed hypophysectomized rats demonstrated an increased rate of ketone bodyproduction as compared to those from fed normal rats. Livers from hypophysectomized rats fasted overnight produced ketone bodies at an increased rate as compared to livers from fed hypophysectomized rats, but the difference was significant only at high FFA concentrations.