R. S. Lillie

Bio: R. S. Lillie is an academic researcher. The author has contributed to research in topics: Osmotic pressure. The author has an hindex of 1, co-authored 1 publications receiving 38 citations.

Maintenance of concentration gradients and regulation of cell volume

Abstract: It has long been recognized that a high surface-to-volume ratio is important to rapidly metabolizing cells that are dependent on ditrusion for supplies of oxygen and nutrients from the surrounding medium. It is also well known that the cell has a high protein content, a significant proportion of which exists in a soluble state in which it may be expected to exert an oncotic pressure. The interstitial fluid bathing the cells, however, is relatively low in its content of colloids. From studies with isotopically labeled tracers over the past twenty years it is now well established that the cell membrane is permeable to water and to all the solutes that contribute significantly to the osmolality of the extracellular fluids. These solutes are largely the salts of sodium. With these facts in mind, one might expect that the oncotic pressure exerted by the intracellular proteins would cause disastrous swelling by drawing fluid from the extracellular compartment into the cells. Such swelling of cells obviously does not occur in healthy tissues in vim One is therefore justified in inquiring into the nature of the forces that normally counteract this tendency toward swelling of body cells and thereby preserve the normal intracellular fluid volume. The maintenance of normal intracellular volume has been shown to be a process requiring energy. In 1949, Stern el al? observed that the swelling of various tissues in vilro was dependent upon tissue respiration. They tested the effect of aerobic versus anaerobic incubation in an isotonic saline medium on the fluid content of various tissues of the guinea pig. Whereas only small changes in weight occurred during aerobic incubation, anaerobic conditions resulted in a consistent, large weight gain attributable to an increased water content of the tissue. This type of observation has been repeated by a number of other workers using various tissues and various means of inhibiting metabolism. Mudge? Robinson: Deyrup,” and Whittam and DaviesK have all repeatedly confirmed this finding, using anaerobiosis, chilling, dinitrophenol, azide, and other methods of interfering with tissue metabolism. In all instances inhibition of metabolism has been found to be associated with increased water content of the tissue studied. A much older observation that goes back at least to Sabbatani’s work6 at the start of this century is that swelling of tissues in vitro can be prevented by substituting hypertonic solutions for the usual isotonic saline media. Gam6ri and Molnar,? Opie,B Robinson: Aebi,” and others have confirmed this finding. The observations that tissue swelling is dependent upon tissue metabolism * The work described in this paper was supported in part by funds from The John A. Hartford Foundation, Inc., New York, N. Y., from the National Heart Institute (Grant H-2822), Public Health Service, Bethesda, Md., and from the American Heart Association, New York, N. Y.