Morphogenesis and metabolism: studies with the cartesian diver ultramicromanometer II. Effect of dinitro- o -cresol on the anaerobic glycolysis of the regions of the amphibian gastrula

Abstract

In the preceding paper of this series a considerable difference in anaerobic glycolytic rate was demonstrated to exist between the dorsal lip of the blastopore in the amphibian gastrula and the ventral ectoderm. It was therefore of some interest to see whether this difference could be diminished or even abolished by any artificial treatment. In recent years there has been a wide extension of our knowledge of chemical substances which inhibit and stimulate the respiration and glycolysis of isolated tissues, but for respiration, which can be acceleraated by the addition of many oxidizable and reducible dyes to acts as accessory hydrogen transporters in the cell, the progress has gone further than for glycolysis. However, the initial discovery of Heymans and Bouckaert (1928) that nitrophenol derivatives have a profound effect on animal metabolism has led to much study of these substances. Our experiments originated from the fact reported by Dodds and Grevile (1934) that dinitro- o -cresol stimulates both aerobic glycolysis and respiration in mammalian tissues. Methods The general technique employed was exactly the same in all particulars as that of the preceding paper, with the exception that the Holtreter-bicarbonate solution used contained 4, 6-dinitro- o -cresol in a concentration of 1 x 10 -5 m, which was shown by Bodine and Boell (1938) to be near the maximally effective concentration in the case of grasshopper embryos. Gastrulae of Rama Temporaria were obtained and prepared for the experiments following the previously described technique. The isolated pieces were in the nitrocresol solution for approximately 40 min. before the manometric reading began; this was the time taken to remove the initial ammonia samples and the excess Holtfreter-bicarbonate solution, and to prepare the divers anaeobically in the filling chamber.