Effect of Testosterone Propionate and Methyl Testosterone on Growth and Skeletal Maturation in Rats

Publisher Website
Google Scholar
Abstract
Female albino rats were treated from age 28 to 70 days with testosterone propionate subcutaneously (0.25, 1.0, 2.5 and 6.0 mg/kg/day) and methyl testosterone by mouth (15, 30, 75 and 150 mg/kg/day). Evaluation of the effects on growth was based on body weight, stem length and tail length measured at sacrifice, and on length of tibia, radius, metatarsal III and metacarpal III measured on prepared bones. Skeletal maturation was assessed on the basis of the state of closure of 42 selected epiphysial plates, as observed on cleared and Alizarin Red S stained skeletons. The body weight of treated animals was increased significantly with both testosterone propionate and methyl testosterone. The effects on the length of individual bones were very small and not consistently significant statistically. Yet a common trend was noted, inasmuch as, with the lower doses of the 2 hormones, the selected bones were slightly longer, whereas this effect was abolished with larger doses and reversed with the largest doses. Skeletal maturation was significantly advanced with the 2 larger doses of each hormone and was not affected by the 2 lower doses. The effect on the ultimate length of bones, which depends upon the balance of the anabolic/androgenic action of the 2 hormones, could be evaluated in the metacarpal and metatarsal bones, which have already stopped growing at the time of sacrifice. Our data (increase of ultimate length with low doses and decrease with large doses) suggest that in the rat this anabolic/androgenic balance is dosedependent.