Arterial and Mixed-Venous Differentials of Free Fatty Acid : Free Fatty Acid Production in Pulmonary Circulation

抄録

Arterial and mixed-venous differentials in con-centration and individual fatty acids of free fatty acid across the human lung were investigated. The effects of intravenous injection of heparin and the addition of linoleate to the diet prior to catheter study were observed. And for the better evaluation of individual fatty acid differentials, the effect of heparin on the lipolysis in systemic circulation was studied in addition. There are positive arterial and mixed-venous differentials (higher in arterial plasma) in free fatty acid concentration and these differentials are augmented noticeably during lipolysis facilitated by a heparin injection. Unsaturated fatty acids of free fatty acid fraction showed a marked increase in their percentage in systemic circulation and a shift toward positive differentials in pulmonary circulation, while saturated fatty acids showed a decrease in systemic circulation and a shift toward negative differentials (higher in mixed-venous plasma) in pulmonary circulation during the early stage of the lipolysis facilitated by heparin. Addition of linoleate to the diet produced an apparent positive differential of linoleic acid of the free fatty acid fraction of plasma lipids. These results seem to suggest strongly that active triglyceride degradation is elaborated in pulmonary circulation as well as in systemic circulation, and seem to give an evidence to the postulations based on animal experiments that the human lung might play an important role in lipid metabolism.