Composition of epiphyseal cartilage

Parathyroidectomy of immature chicks and subsequent administration of parathormone effected, within 24 hours, changes in the composition of the epiphyseal cartilage. These changes can be summarized as follows:

1. Parathyroidectomy increased the levels of collagen constituents and decreased those of calcium, while the levels of hexosamines and of ash remained the same as in controls.
2. Parathormone corrected the effect of parathyroidectomy on the collagen constituents; the levels of calcium and of ash were increased above those of the intact chicks; the levels of hexosamines remained unchanged.