A Pituitary Growth-Promoting Factor for Articular Chondrocytes in Monolayer Culture

Abstract

A heat-labile anterior pituitary factor exerts a strong mitogenic action on articular chondrocytes in secondary monolayer culture. At the same time secretion of macromolecular radiosulfate into the medium by the stimulated cells is markedly reduced. This factor was found in NIH bovine and ovine TSH as well as LH but not in more purified (Condliffe-Bates, Pierce) preparations of TSH. The response, measured by the DNA content of the cell pellet, was dose-dependent; the lowest effective concentration was 1 μg NIH TSH/ml culture medium. The effect was fairly selective for chondrocytes, rabbit and human, and was displayed to much lesser degree by skin fibroblasts and 4 other cell types studied. FSH had a smaller effect while GH, prolactin, ACTH and a preparation having high EPS activity were relatively ineffective. Of 19 other hormone preparations examined, only crude HCG gave a comparable mitogenic response. Insulin, 0.1 U/ml, had a consistent but small effect. Estradiol-17β and diethylstilbesterol (10 μg/ml) were cytotoxic, as were cyclic AMP and its dibutyryl ester (1.4 × 10–3M). (Endocrinology90: 262, 1972)