Growth Inhibitor in Liver Tissue

Abstract

Liver has been known for a long time to contain substances which inhibit growth and migration of cells from explants. Walton 1 observed that extracts of liver had an inhibiting effect on tissue cultures, in contrast to all other tissue extracts tried. Lynch 2 and Lewis 3 noticed that no cells migrate from cultures of chick embryo liver after the sixteenth day, and it has been suggested that the inhibitor in liver may be responsible for this effect. Despite the great amount of work that has been done on extracts and substances which increase growth of tissues in vitro or make possible their prolonged cultivation, relatively little attention has been paid to inhibitors. The following is a report of investigations made in this laboratory on the inhibiting power of liver extract.

We have used, in general, first explants of embryonic and sarcomatous tissues, grown by the usual coverslip or Carrel flask techniques in solid plasma media. In order to get a quantitative measure of inhibition, we have compared the average radial growth in a test solution at a given time with that in a control medium consisting of plasma and Tyrode's solution, using tissues explanted at the same time from the same embryonic organ. Of course, Parker 4 has shown that the growth rates of fibroblasts from different parts of the same organ may vary; we have found, however, that by using series of 5 or more explants a growth index can be obtained which does not vary more than 10 or 15% from series to series, or from day to day in the same series.