Cytochemistry of marrow and extramedullary adipocytes in monolayer cultures

The behavior of isolated, disaggregated white adipose cells obtained from marrow and extramedullar sites in the rabbit was compared in monolayer cultures. Both cell types transform within 2 weeks into fibroblast-like cells which can be maintained in subcultures. Both in freshly isolated state and in fibroblast-like state the marrow adipocyte contains esterase activities reacting with naphthol AS acetate and D-chloracetate. These activites are not present in extramedullary cells. In addition, alpha-naphthyl butyrate-reacting esterase, present in both cell types, is fluoride-resistant in marrow adipocytes but labile in extramedullar cells. These differences are consistent with heterogeneity of white adipose tissue and suggest different potentials for marrow and extramedullary adipocytes.