A simple fluorescent method for quantitative determination of aortic protein uptake.

A quantitative system for direct protein tracing and measurement of net protein uptake in the aorta using fluorescein isothiocyanate conjugated bovine serum albumin (FITCBSA) is described. Using Wistar rats, a mean aortic FITCBSA net uptake of 29.7 times 10(-17) g FITCBSA per mum2 aortic endothelial surface area per 24 h was obtained. Intra-aortic localization of the FITCBSA was observed along the endothelium and the collagen-elastin bands. The values obtained using this FITCBSA system are comparable with those of a previously established isotopic technique measuring aortic albumin flux and reconfirm the previous findings of the existence of an albumin permeability gradient in the thoracic aorta.