Capillary filtration coefficient: the technique and its application to the small intestine.

In this review, we discuss the physiological basis of the capillary filtration coefficient (Kf,c), and its measurement in the small intestine. First the various techniques by which Kf,c can be measured are discussed and assessed; the second part of the review considers the volumetric method of determining Kf,c in more detail, in an attempt to identify the causes of variability in published values for intestinal Kf,c. Finally, we discuss changes in intestinal Kf,c due to sympathetic nerve stimulation and the administration of drugs and hormones. The majority of estimates of intestinal Kf,c are about 0.38 to 0.60 (innervated) to 0.60 to 0.75 (denervated) cm3 . min-1 . kPa-1 . 100g-1. These values are increased by most vasodilator drugs and hormones, and decreased by sympathetic nerve stimulation and by vasoconstrictor drugs.