The oxygen consumption, fatty acid and glycerol uptake of the liver in fed and fasted sheep during cold exposure.

Abstract

The effect of a short period (3—4 hr) of exposure to cold on the liver's circulation and metabolism has been studied in sheep fed 6 hr or 21 hr before experiment.In the cold the animals had a significantly increased heart rate, cardiac output, hepatic portal blood flow, mean arterial blood pressure and pulse pressure. Total peripheral resistance fell in the fasted animals when they were exposed to cold, but not the more recently fed animals. Exposure to cold significantly increased the total body oxygen consumption and oxygen consumption of the liver, but not that of the portal‐drained viscera (gut, spleen, pancreas, omental adipose tissue). Recent feeding significantly increased the net rate of release of volatile fatty acids from the portal‐drained viscera, and significantly increased their net rate of uptake by the liver. In the recently fed animals, exposure to cold further increased the visceral release, portal plasma concentration, and hepatic uptake of volatile fatty acids. Exposure to cold, and fasting, both significantly increased the circulating (arterial) plasma level of free fatty acids and glycerol, and increased their net rate of uptake by the liver, significantly in cold exposure but not in fasting.The results show that the liver makes a small contribution to the total increase in oxygen consumption in the cold. The liver also has an increased uptake of fatty acids and glycerol during cold exposure.