GONADAL HORMONES, CHONDROGENESIS AND OSSIFICATION IN THE YOUNG FOWL

Abstract

Hormonal control of cartilage growth and differentiation was investigated. Daily administration of 100 [mu]g estradiol benzoate for 7 to 8 days produced a significant narrowing of the proliferation zone in the epiphyseal discs of the femur, tibiotarsus and tarsometartarsus of Rhode Island Red chicks. A diminution in the extension of the hypertrophic cartilage area was also seen and it was suggested that this effect is partly due to enhanced endochondral esteogenesis. There was also a dwarfing effect on the 3 long bones. Testosterone proprionate in a daily dose of 300 [mu]g for 9 days decreased the width of the epiphyseal disc but the differences were not statistically significant. Progesterone in a dose of 500 [mu]g/day for 8 days had no significant influence.