Species differences in the expression of caseinolytic proteinases and plasminogen activators by bone marrow cells

Intact viable bone marrow cells from hamsters (Mesocricetus aruatus), rat (Rattus norvegicus), guinea pig (Cavia porcella) and rabbit (Oryctolagus cuniculus) were analyzed for caseinolytic proteinases and plasminogen activator activity. Species specific quantitative and qualitative differences in caseinolytic activity were detected. Quantitative and qualitative differences in plasminogen activator expression were observed. Cellular fractionation experiments revealed a heterogenous distribution of plasminogen activator activity among subpopulations of cells. The plasminogen activator activity associated with bone marrow cells behaved as ectoenzymes. These results indicated that different species may regulate bone marrow cell proteinase activity in a species-specific manner, compatible with their unique regulatory requirements.