Erythrocytosis in thiamine deficient rats.

A thiamine (T) deficient state in rats was produced by feeding the rats a T deficient diet (TDD). At the stage of 13 days (TDD13 group), the number of red blood cells (RBC) and white blood cells (WBC), hematocrit (Ht) and hemoglobin (Hb) values decreased. On the other hand, after 30 days on the TDD (TDD30 group), the number of RBC was 819 x 10(4)/mm3 as against 631 x 10(4)/mm3 in the normal control group (NC group). Ht and Hb values also increased in the TDD30 group. These changes observed in the TDD30 group were significantly different from findings in the equal weight control group (EWC group) or in the pair fed control group (PFC group). The number of reticulocytes increased, the levels of 2,3-diphosphoglycerate (2,3-DPG) of RBC decreased and plasma erythropoietin levels increased in the TDD30 group. T levels of blood in the TDD13 group were 62 (39-79) ng/ml as against 275 (196-412) ng/ml in the NC group. T levels of blood in the TDD30 group were 102 (17-365) ng/ml, and widely varied. Decrease in 2,3-DPG produces an increase in O2 affinity to Hb, and hypoxia is induced in the peripheral tissues. Furthermore these conditions stimulate erythropoietin production and finally the number of RBC increases. T deficiency produces anemia at an early stage and absolute erythrocytosis occurs at the late stage of T deficiency. The increased osmotic resistance of RBC in hypotonic solution was also observed in the TDD30 group. This increase in osmotic resistance correlated with the decrease in cholesterol and phospholipid levels in the membrane of RBC.