TOTAL CIRCULATING PROTEIN AND HEMOGLOBIN IN THE GROWING RAT

Abstract

The following conclusions are qualified by the relative smallness of the sample from which they are drawn: Unit (ml./100 cm.2) blood and plasma vol. attain their adult values coincident with pubescence. Unit total cell. vol. increases exponentially until the rat reaches maturity. No significant increase in Hb conc. is noted until after puberty. The increase thereafter is almost linear. The adult value is attained coincident with maturity. Unit total circulating Hb gradually increases until the adult value is attained with maturity. The total mean corpuscular Hb conc. (ratio of circulating Hb to circulating erythrocytes) does not change with growth. Plasma protein conc. increases exponentially until the adult value is attained shortly after puberty. The unit total circulating plasma protein is maximal at puberty and normally is relatively constant thereafter. These phenomena observed in the rat are similar to those reported for the human at comparable stages of development. In the interpretation of quantitative changes of plasma protein and Hb reference to total circulating amts., rather than conc. probably affords a better physiologic estimate.