The Effect of Single Intraperitoneal Injections of Certain Carcinogenic and Non-carcinogenic Hydrocarbons on the Growth of the Rat *

During the course of a study of the effect of the oral administration of certain polycydic hydrocarbons on the growth of the rat,7 a paper by Haddow, Scott, and Scott2 appeared which reported that growth retardation had been produced in the rat by a single intraperitoneal injection of certain carcinogenic hydrocarbons. These authors further observed that similar injections of non-carcinogenic compounds caused no retardation of growth. Experiments were initiated with the view of attempting to produce growth retardation in the manner reported by Haddow, Scott, and Scott, in order to study the effect of the oral administration of sulfur-containing amino acids on the inhibited growth rate. Moreover, it was desired to examine carefully the striking claim2 that differences could be obtained in the growth effects produced by the intraperitoneal injection of carcinogenic as contrasted to noncarcinogenic substances. It is the purpose of this communication to present data on the effect of single intraperitoneal injections of certain carcinogenic and non-carcinogenic hydrocarbons on the growth of the rat. The reported existence of definite differences between the influence of carcinogenic as contrasted to non-carcinogenic hydrocarbons on the growth rate of the rat has been demonstrated not to exist provided an appropriate quantity of each of the various hydrocarbons is employed. These data, considered together with those obtained in a study of the growth-inhibitory effect of certain carcinogenic and non-carcinogenic hydrocarbons,7 suggest that growth inhibition is related to the toxicity of an administered substance; this toXIcity may