Sebaceous gland suppression as a short-term test of the cutaneous carcinogenic activity of mineral oils

Forty-seven mineral oils were tested for their ability to induce sebaceous gland suppression in female C3H/HeN or CF1 mice. Six groups of five mice were treated with zero, one, two, three, four or six epidermal applications of one or more of three volumes (0.2, 0.1 or 0.05 ml) of the test substance. The sebaceous gland suppression indices were calculated from the total numbers of sebaceous glands and hair follicles in nine sections of treated skin from each mouse. Suppression curves were drawn by plotting the mean suppression indices against the number of applications of each oil sample. The suppression curves were compared with the cutaneous carcinogenic potentials of these mineral oils, assessed by long-term skin bioassays. All the carcinogenic oil samples induced suppression of sebaceous glands. The non-carcinogenic samples had no significant suppressant activity. There was a correlation between cutaneous carcinogenic activity and suppressant potential for all tested samples. Results of the suppression tests considered, together with the kinematic viscosities of the test substances, enabled accurate prediction of their cutaneous carcinogenic potential.