Beryllium Effects on Aryl Hydrocarbon Hydroxylase in Rat Lung

Abstract

This study was undertaken to determine whether beryllium would interfere with pulmonary mixed function oxidases. Rats were injected intratracheally with 150 μmols/kg of a neutralized solution of beryllium sulfate (BeSO₄). The activity of pulmonary aryl hydrocarbon hydroxylase (AHH) was measured one, two, and seven days, and two and four weeks after beryllium injection. The specific activity of AHH seemed to be lowered by beryllium; however, if the data were calculated as total AHH activity per lung, changes were much smaller and detectable only within the first two days after beryllium exposure. Beryllium did not prevent the induction of pulmonary AHH by methylcholanthrene. RNA synthesis in rat lung exposed to beryllium was higher than in controls, probably because of the acute chemical pneumonitis produced by beryllium. The results do not support the hypothesis that beryllium could act as a pulmonary cocarcinogen by interfering with the metabolism of carcinogenic polycyclic hydrocarbons in the lung.