The relationship of total red cell volume to total body water in octogenarian males.

By Smmcio PIOMELLI, DAviD G. NATHAN, JAMES F. CUMMINS, AND FRANK H. GARDNER With the technical assistance of Alvera L. Liniauro I HE MAINTENANCE of red cell volume in man depends upon constant production of erythrocytes to replace effete cells destroyed following their 120 day sojourn in the circulation. The bone marrow performs this function in a singularly constant manner in man, renewing the red cell population at a rate of approximately 0.8 per cent per day. The physiologic stimuli which control erythropoiesis have been studied in detail,1’2 and the results of such studies have led to the conclusion that the oxygen demands of the tissues strongly influence red cell production. Recent evidence indicates that the kidneys may act as “oxyreceptors” and elaborate crythropoietin to stimulate stem cell differentiation to enythroblasts,4 in response to a demand for increased circulating oxygen carrying capacity. Erythroid marrow recognition of tissue oxygen requirements is manifested by the close relationship of the total ned cell volume to the “lean body mass” ( as estimated by measurement of total body water ) in normal young adults.57 Such studies have established predictable and reproducible normal values for total red cell volume as it relates to body water in young individuals. Previous examinations of the relationship of total ned cell volume to body weight in elderly people 1#{176} have led to confficting opinions. Some of the data indicate a reduction of tctal red cell volume9 whereas other studies imply that no significant reduction occurs.8”#{176} Interest in the physiologic control of erythropoiesis has prompted our investigation of the relationship of total red cell volume to body water and to body weight in healthy octogenarian males. This study has been performed in an attempt to establish predictable normal values for red cell volume in the elderly and to define the range of variation of red cell volume in apparently healthy octogenarians.