[Metabolism of paraffinic and naphthalenic hydrocarbons in higher animals. I. Retention of paraffins (normal, cyclo and branched) in rats].

Apparent retention of aliphatic hydrocarbons in the Rat is studied. Animals weighing 150 g are put into metabolism cages and given a 15 mg dose of one of the paraffins studied in solution in the peanut oil of the ration. There is no urinary excretion, and fecal elimination is low (5-10%), as long as the carbon chain stays below 24 atoms. Real retention is measured on animals recieving a single dose of 15 mg in the same conditions. Branched paraffins give only very low residual amounts 15 days after ingestion, while n-paraffins and cyclo-paraffins remain unchanged in the carcass, as long as the number of carbon atoms is not greater than 20; the proportion of the latter paraffins is about 8% of the dose ingested (5 days as 21 days after intake). Beyond C 20, real retention decreases rapidly to zero.