THE PRODUCTION OF SEBUM IN YOUNG RATS: EFFECTS OF AGE, SEX, HYPOPHYSECTOMY AND TREATMENT WITH SOMATOTROPHIC HORMONE AND SEX HORMONES

Abstract

SUMMARY The secretion rate of sebum in rats aged 3–14 weeks was determined by measuring the amount of acetone-extractable skin surface lipids produced during 2 days. The results were expressed as mg. sebum/100 g. body weight/2 days. The secretion rate of male rats was found to increase with age (from 16 mg./100 g. at 3 weeks to 35 mg./100 g. at 14 weeks), while that of female rats (16 mg./100 g.) remained unchanged. Hypophysectomy of 3-week-old female rats resulted in lowering of the secretion rate to 13 mg./100 g. at 10 weeks. No change in the secretion rate of the hypophysectomized animals occurred during either growth hormone or oestradiol treatment, but testosterone in doses of 1 mg. and 0·2 mg./day increased sebum production (to 37 mg./100 g. and 24 mg./100 g., respectively). The increase obtained with testosterone (0·2 mg./day) was smaller (20 mg./100 g.), when oestradiol (3 μg./day) was given simultaneously.