The mechanism of functional vasodilatation in rabbit epigastric adipose tissue.

1. The effect of close-arterial infusions of fat-mobilizing substances has been examined on the release of free fatty acids and blood flow in the epigastric adipose tissue of rabbits.2. All the fat mobilizers in addition to causing the release of free fatty acids also caused an increased blood flow in the fat tissue.3. Both the fat mobilization and the vasodilatation continued for an hour or so after the end of infusion.4. Although no vasodilator substance could be detected in the venous effluent from the activated adipose tissue, a vasodilator could be detected in acid-ether extracts of adipose tissue excised during a period of fat mobilization.5. It is suggested that a vasodilator substance is released or formed in adipose tissue during fat mobilization and that this substance accounts for the vasodilatation accompanying activity in the tissue.