The influence of certain carcinogenic and other hydrocarbons on body growth in the rat

Abstract

Selected groups of Lister rats, 55 dys. old in most expts., were checked for normal growth rate, then injected intraperit. with 1-3 doses of the hydrocarbon in 0.5 to 1.0% soln. Immediate, prolonged and constant depression of the growth rate was obtained with dosages of 0.3-90 mg. 12:5:6-dibenzanthracene, 10 mg. benzpyrene and l:2:5:6-dibenzacridine. 30 mg. chrysene had less effect than 0.3 mg. dibenzanthracene. No recovery of growth rate was evident during the period of expt., 26-100 dys. Phenobarbitone had no effect on growth rate, do-decahydro-1:2-benzanthracene and fluoranthene in doses of 30 mg. produced temporary depression followed by complete recovery, as did the toxic substances lead nitrate (4 mg.) and colchicine (0.21 mg.). X-rays of 0.4 A[degree] in a dose of 450 r through a 0.01 mm. aluminum screen produced temporary inhibition only. Apart from the growth effect, the carcinogenic compounds depressed ovulation and spermatogenesis and increased susceptibility to infection. Their effect on growth is not a direct toxic effect, and may possibly outlast their presence in the body. No evidence of the presence of 1:2:5:6-dibenzanthracene could be found in 37 and 105 dys. after doses of 3 and 10 mg. respectively, though growth was still depressed. Controls in all cases came from the same litters as the injected rats.