Autoregulation of blood flow in human adipose tissue.

Abstract

AbstractThe presence of autoregulation of blood flow was investigated in subcutaneous adipose tissue of the distal part of the forearm by means of the local xenon‐133 washout technique. 89 studies were performed on 4 healthy subjects. Blood pressure changes were obtained by passive displacement of the investigated area to various test levels above and below the reference level, the jugular notch. Above heart level, where venous pressure was constant, elevation of the arm to a level corresponding to an arterial blood pressure reduction of 20 mm Hg did not alter adipose tissue blood flow. At higher elevation autoregulation was not seen as blood flow fell in proportion to the reduction in perfusion pressure. Below the heart, where arterial and venous pressures in the forearm increase in parallel, blood flow in subcutaneous tissue remained constant. This indicates adjustments in arteriolar resistance to oppose the distending force of the increased transmural pressure. In this orthostatic pressure range blood flow was maintained until a level corresponding to an increase in pressure of about 15 mm Hg beyond which blood flow was reduced to about 60 per cent.