Summary
A series of hydrocarbons was applied to mouse skin, and the hyperplastic responses, as well as the changes in skin sterols were measured. Most of the compounds increased the weights of the epidermis without any significant change in the dermis.
Methylcholanthrene (MC) in acetone caused a hyperplasia and a marked increase in cholesterol with a simultaneous decrease in Δ7-cholestenol. Related carcinogens produced similar effects. MC in mineral oil lowered the concentration of Δ7-cholestenol without any appreciable hyperplasia or increase in cholesterol.
Straight-chain saturated hydrocarbons caused hyperplasias which reached a maximum with tetradecane. These compounds failed to alter the amount of Δ7-cholestenol present, but substantial increases in cholesterol paralleled the increases in epidermal weight. Effects due to the mono-unsaturated hydrocarbons were quite similar to those due to the saturated hydrocarbons, with similar effects on the skin sterols.
While benzene had no effect on skin, several of its alkylated derivatives caused marked hyperplasias with parallel increases in cholesterol. But the amount of Δ7-cholestenol in the epidermis remained unchanged, except after the application of cyclohexylbenzene, which caused it to decrease.
Hyperplasia involving an increase in epidermal weight of over 200 per cent was accompanied by an increase in unesterified Δ7-cholestenol and in some cases by an increase in unesterified cholesterol.
Mineral oil fractions produced effects similar to those due to pure aliphatic or aromatic compounds of similar structure. The so-called naphthene-rich fraction lowered Δ7-cholestenol, without causing hyperplasia.
The evidence available suggests that the Δ7-cholestenol of normal mouse epidermis is located in the sebaceous glands.
Published with the approval of the Director of the Wisconsin Agricultural Experiment Station. Supported in part by Grant C-2177, National Institutes of Health, U.S. Public Health Service.
Most of these results are contained in a thesis entitled “Contrasting Effects of Certain Organic Compounds on Skin Sterols and on the Epidermis” by S. C. Brooks, University of Wisconsin, June, 1955, in which the experimental procedures and the variations in results are recorded in considerable detail.
