Marrow adipose tissue: Response to erythropoiesis

Abstract

Abstract A group of rabbits was treated chronically with phenylhydrazine to induce hemolysis and stimulate erythropoiesis. The mean volume of the marrow fat cell of a control group of hematologically normal rabbits was 54.8 pl; the mean volume of the perinephric fat cell was 549.5 pl, a volume ratio, perinephric/marrow of 10: 1. In the experimental animals the mean volume of the marrow fat cell fell to 25.9 pl; the volume of the perinephric fat cell was unchanged and the volume ratio, perinephric/marrow was 18: 1. Fat cell volume studies performed on rabbits subjected to chronic bleeding yielded comparable data. The l‐C 14 palmitate uptake (esterification capacity) calculated on a cell basis was the same for both marrow and perinephric fat cells and was unaffected by phenylhydrazine treatment. The fatty acid composition shows higher content of unsaturated fatty acids in the marrow fat than in the perinephric fat of the control animal. In the experimental animal there appears to be a preferential release of the unsaturated fatty acid. The findings of the study suggest that increased hematopoiesis stimulates lipolysis of marrow fat cells, probably through the local release of a chemical substance. Marrow fat appears to be functionally related to hematopoiesis rather than to systemic fat storage. Marrow fat may be involved in the metabolic support of hematopoiesis.