Effects of calcitonin and parathyroid hormone on the metabolism of chondrocytes in culture

Abstract

Rabbit articular chondrocytes in suspension culture synthesize Type II colagen [3 α 1(II)] in the absence of extracellular Ca 2+ and Type Icollagen [2 α 1−(I)· α 2] in the complete medium. As a result of pre-treatment in monolayer culture with calcitonin or parathyroid hormone in the complete medium, an influx of Ca 2+ into the cells occurs. These cells produce mainly Type I collagen when transferred to suspension cultures in the medium devoid of CaCl 2. If added directly to the suspension culture medium containing no CaCl 2, calcitonin stimulates an active efflux of Ca 2+ from the cells into the medium and leads the cells to synthesize Type I collagen. Under similar conditions, parathyroid hormone does not change the collagen-phenotype.