Measurement of Thrombocytopoiesis in W/W v Mice with Evidence for an Abnormality of Sulfate Metabolism 1

Abstract

Abstract

Mice of the W/W^v genotype have an hereditary macrocytic anemia resulting from a diminished proliferative capacity of hemopoietic precursor cells. Platelet production was studied because W/W^v mice maintain a normal number of circulating platelets that are of normal size in spite of a diminished number of megakaryocytes. Using [⁷⁵Se]selenomethionine and calculating the percentage of the injected dose incorporated by platelets, the platelet production rate of W/W^v mice was found to be equivalent to the production rate of their +/+ littermates. Using Na₂ ³⁵SO₄ however, the platelet production rate, as measured by the same isotope incorporation method, was nearly twice the rate of the normal littermates. The increase in ³⁵S incorporation appeared to be explained by a greater availability of isotope in the W/W^v as evidenced by the higher plasma levels of ³⁵S that were concurrently found. This suggests that the W/W^v mouse has an aberrant metabolism of inorganic sulfate probably unrelated to platelet production. These results also demonstrate how failure to take plasma radioactivity levels into account can lead to conflicting and probably erroneous conclusions in animals with an inherent or induced metabolic abnormality.