Substances that Aid or Inhibit the Inducing Effect of Inducers

Substances that Aid or Inhibit the Inducing Effect of Inducers 

Studies of porphyrin production in rats treated with DDC by gastric tube (300 mg/kg) revealed a decrease in liver ATP of 50% within 2 hours, while porphyrins increased continuously between 2 and 6 hours. On the other hand, intravenous administration of high doses of ATP was found to decrease the porphyria [Gajdos and Gajdos-Torok, 4]. Studies on chick embryo liver cells suggested that the decrease in porphyrin formation may not have been due to a lowering of ALA-synthetase activity but rather to an effect on some intermediate steps of heme biosynthesis [128]. When ATP, NADPH, ascorbate, orpiperonyl butoxide was added to the culture medium, porphyrin formation was diminished but ALA-synthetase activity was not appreciably affected. 

The effect of ethanol appears to result in an increase in porphyria according to data in the literature, but no definitive statement can as yet be made. A difference in the results is observed in acute or chronic intoxications, and conflicting statements have appeared as to the involvement of a microsomal oxygenase system. 

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