BIOLOGICAL BARRIERS AND MEDICINE

Career support provides the essential element needed for the detailed development of thematic areas of inquiry. Dr Goresky outlines how care er support provided for him the substratum for the investigation and d efinition of tracer exchange processes in the liver. Classical interst itial substances (labeled albumin, inulin, sucrose, and sodium) and la beled water were found to undergo flow Limited distribution in the Liv er. An excluded volume phenomenon created systematic variation in acce ssible interstitial space (that is, Disse space) values, smaller for l arger molecular weight substances. Labeled rubidium entered liver cell s in a concentrative fashion (return from cells was very small, early in time). Labeled glucose liver cell entry was found to exhibit the ch aracteristics of a carrier-mediated membrane transport process. Labele d galactose showed saturation of intracellular sequestration, as well as of the cell entry process, the former at much lower galactoseconcen trations. Straight-chain labeled monohydric alcohols were found to ent er Liver cells in a flow-limited fashion. Labeled ethanol consumption, when related to underlying steady ethanol values, exhibited Michaelis -Menten kinetics. A substantial extra intracellular enzymic space of d istribution was found for the C-3- and C-4- straight-chain alcohols, p redicted by the kinetics. Development of the tracer approach allowed t he differentiation and characterization of the processes by which subs tances penetrate the cell membrane barrier and those resulting in intr acellular sequestration.