Inverse Changes in Erythroid Cell Volume and Number Regulate the Hematocrit in Newborn Genetically Hypertensive Rats

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 88; no. 21; pp. 9848 - 9852
• Main Authors: Boylan, John W., Van Liew, Judith B., Feig, Peter U.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01-11-1991; National Acad Sciences
• Subjects: Age Factors; Animals; Animals, Newborn; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood; Blood and lymphatic vessels; Cardiology. Vascular system; Erythrocyte Count; Erythrocyte Volume; Erythrocytes; Erythrocytes - cytology; Erythroid cells; Erythropoiesis; Experimental diseases; Hematocrit; Hemoglobins; Hemoglobins - chemistry; Medical sciences; Oxygen; Polycythemia; Rats; Rats, Inbred SHR - blood; Rats, Inbred Strains; Rats, Inbred WKY - blood; Hypertension; Rat; Rodentia; Red blood cell; Cardiovascular disease; Hereditary; Vertebrata; Experimental disease; Regulation(control); Mammalia; Animal; Hematocrite; Cell volume
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.21.9848

Erythrocytosis and microcytosis have been described in strains of genetically hypertensive rats and in essentially hypertensive humans. Published discussion of these phenomena has centered around their relationship to observed alterations in ionic transport and the pathogenesis of hypertension. In presenting data for another strain of spontaneously hypertensive rats in which these findings are exhibited, we note that erythroid cell size decreases concurrently with the increase in cell numbers so that the hematocrit and the mean corpuscular hemoglobin concentration remain constant. Data from the literature support the hypothesis that erythroid cell size is inversely proportional to cell count in a large number of species. Erythrocytosis, as it develops in the neonatal rat, is a consequence of the marked immaturity of this species at birth. Erythrocytosis in the spontaneously hypertensive rat is not due to a difference in the affinity of its hemoglobin for oxygen or to significant tissue anoxia. Microcytosis in the spontaneously hypertensive rat is the consequence of a continuation of the linear volume decrease with age of its erythroid cells seen in the normotensive animals and may be accounted for by the production of smaller cells with concomitant regulation of individual cell volume.