Actions of isotretinoin and etretinate on the pilosebaceous unit.

Isotretinoin administered subcutaneously to male hamsters results in marked involution of the sebaceous glands of the flank organ without discernible effort on the other androgen-dependent structures, pigmented hair follicles, and dermal melanocytes. Treatment of androgen-stimulated female hamsters with isotretinoin prevented the androgen-induced growth of the sebaceous glands but not the formation of large pigmented hairs and dermal pigment cells. Etretinate, in comparable dosage, did not show the inhibitor effect on sebaceous gland growth. The hamster flank organ seems a promising system for assessment of the sebaceous gland inhibitory activity of retinoids and may be predictive for therapeutic activity in acne.