Some aspects of phosphorus metabolism in bone marrow

Abstract

A study has been made of the P content of bone marrow in rabbits and rats, with special reference to acid-soluble, adenosinetriphosphate, and nucleic acid P. During in vitro incubation, enzymes present in the bone marrow caused a decrease in difficulty hydrolysable P esters and an accumulation of inorganic P; an increase in total acid-soluble P, particularly marked in rat bone marrow, and a fall in nucleic acid P, chiefly at the expense of ribonucleic acid. Adenosinetriphosphate was relatively stable under aerobic conditions, but broke down more rapidly in absence of oxygen. The ammonia formed exceeded by many times the content of preformed adenosinetriphosphate amino N, especially in rat bone marrow. Alterations in food composition leading to undernourishment or vit. deficiency in rats markedly lowered the content of nucleic acid P in the bone marrow. The behavior of the P compounds in the bone marrow was investigated at various stages of systemic poisoning with mustard gas and mustard sulfoxide, and also in rats and rabbits which received single doses of X-rays over the whole body. A pronounced fall in nucleic acid P occurred; changes in the desoxyribonucleic/ribonucleic acid ratio suggested that desoxyribonucleic acid was more strongly affected than ribonucleic acid: a lowered content of adenosinetriphosphate and total acid-soluble P was also observed. In surviving animals, paralleling general recovery, there was a gradual return to normal in these P fractions of the bone marrow. The significance of nucleic acid P assay as an indicator of the metabolic potential of the bone marrow is discussed.