Autoradiographic studies with 35S-sulfate on somatotrophin and estrogen sensitivite growth zones in rat and mouse costal cartilage.

Abstract

AbstractAn autoratliographic study was performed on the regional pattern of incorporation of 35S sulfate in different anatomical regions of costal cartilage in growing mice and rats in uivo and in vitro. Profound regional differences in sulfate incorporation rate have been revealed between the medial or “resting” part of costal cartilage and the “active” growing region of the rib which is located in close association with the osteochondral junction. The regional pattern of sulfation activity showed great similarities in the rib cages of rats and mice. The increased sulfate incorporation activity in the growth region of mouse rib cartilage was also maintained when the rib cage was incubated in vitro with 35S‐sulfate. Hypophysectoniy almost completely abolished, and somatotrophin treatment of hypophysectomized mice with 500 μg GH‐NIH‐S8 for 10 days restored the rate of sulfate uptake to above normal levels in the growth zones of the ribs. A 10 clay treatment with a daily dose of 100 μg estradiol Iienzoate per mouse caused a pronounced fall in the sulfate incorporating activity of the growth region and markedly narrowed the “active” zone of the costal cartilage.