Studies on kidney tubulogenesis VI. Survival and nucleic acid metabolism of differentiating mouse metanephrogenic mesenchyme in vitro

Abstract

Abstract Results obtained from analysis of the early development of embryonic cells under tissue culture conditions apparently reflect both true developmental events and artificial changes consequent upon the isolation and transplantation of the tissues. The magnitude and mechanisms of such changes were examined in a model system, the differentiating metanephrogenic mesenchyme of mouse embryos, which we have used for several analytical studies in developmental biology. The results indicate that isolating and transplanting this tissue to organ culture conditions causes a marked decrease in nucleic acid metabolism, as measured in incorporation experiments. This lag period extends through the first 20 to 30 hours of in vitro cultivation, after which normal metabolism is restored. The change does not seem to be related to cell loss, since viability counts reveal only a small percentage of cells to be dying during this period. Adding Zn ++ ions to the culture medium had a favorable effect on the incorporation of nucleic acid precursors during the lag period, suggesting that the enzyme treatment employed during isolation might have removed bivalent cations from this tissue.