Action of X-rays on Glutathione Content and Oxygen Consumption of Normal and Regenerating Planarians. ∗

Abstract

Studies upon regeneration 1 have been carried out to test the hypothesis that persistent embryonic cells are responsible for the formation of new tissues during regeneration, and that the power or capacity for regeneration is to be correlated with the number of such cells present. It has been shown that in different species of planaria, cells of an embryonic type, called “formative cells,” undergo rapid proliferation after cutting the planarian, migrate to injured areas, and differentiate into the new tissues characteristic of the regenerating part. Species of planarians that exhibit the greatest capacities for regeneration possess the greatest numbers of these formative cells. Hickman 2 destroyed the capacity for regeneration by the use of X-rays and radium, and histological studies of such irradiated worms showed a selective destruction of these formative cells.

Other investigators showed that the rate of metabolism and of oxygen consumption in particular, increase immediately after cutting and remain at a high level throughout regeneration. The important rôle of glutathione in the establishment of the metabolic level and in the utilization of oxygen indicated that important correlations might be found between the processes of regenerative development and the quantitative distribution of this compound. Numerous workers have found glutathione in greater concentrations in the tissues of embryos and in adult tissues capable of continued cell division than in adult tissues in general. Recently Hammett 3 has shown glutathione to be a stimulus to cell division.

Using a modification of methods of Joyet-Lavergne 4 and Hammett 3 the glutathione content was determined in two species of Turbellarians, Planaria agilis, and Procotyla fluviatilis (Dendrocoelum lacteum). The former species possesses a high capacity for regeneration and shows a high concentration of glutathione; the latter, which exhibits a low capacity for regeneration, shows a lower content.