Hamster ear model for sebaceous glands.

The ventral side of the earlobes of Syrian hamsters richly endowed with sebaceous glands. These glands are large and are similar to human sebaceous follicles since they have an infundibulum, a sebaceous duct, multiple lobules, and a pilary unit which enters from below into the gland. In this study we have measured gland size by planimetry,and cellular activity by autoradiography using tritiated thymidine and tritated histidine. Males have much larger glands in sagittal sections than do females(0.1750 mm2 vs 0.0727 mm2, p less than 0.001) and a higher labeling index (19.85% vs 14.3%, p less than 0.01). Injection of testosterone propionate increases the gland size in female hamsters to 0.2362 mm2 (p less than 0.001). The labeling index also increases. The turnover of the total gland population is 12 to 14 days. Androgen sensitivity, gland size, and turnover time make the sebaceous glands on the ventral surface of the hamster earlobe a suitable model for study.