Morphometric evaluation of sebaceous gland volume in intact, castrated, and testosterone-treated rats

Starting a 19 weeks of age six male rats, castrated at 16 weeks, were injected intramuscularly three times per week with 0.25 mg testosterone propionate (dissolved in sesame oil) per 100 grams body weight. Four castrated control rats received sesame oil only. Samples of dorsal skin were taken under light ether anesthesia at the time of orchidectomy and at weekly intervals during treatment. Histologic sections were cut perpendicular to the skin surface, stained with hematoxylin and eosin, and analyzed morphometrically for their volume content of sebaceous glands, A square grid of 42 sampling points was superimposed on each microscopic field at a maganification of 300X and an average of about 1000 points were counted over the entire thickness of the skin in each section. The average thickness of the skin was also determined for each sample. Three weeks after castration the mm-3 of sebaceous glands per cm-2 of skin was reduced from 1.76 to 0.96, a difference that is statistically significant at p is less than 0.005. One week after starting testosterone injections, the volume of sebaceous glands was more than double that in the control animals: 3.0 vs 1.2(p is less than 0.02). Even greater differences were found at 2 to 4 weeks of treatment.