In vitro effects of growth hormone and other hormones on chondrocytes and osteoblast-like cells.

The influence of growth hormone (GH), insulin-like growth factor I (IGF-I), parathyroid hormone(1-34) (PTH(1-34)), 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 17 beta-oestradiol on proliferation and on production of cytokines, such as interleukin-1 beta (IL-1 beta), IL-6, IL-8 and transforming growth factor-beta (TGF-beta), was studied in chondrocytes obtained from the growing cartilage of the iliac crest and in the osteoblast-like cell clone SaOS-2. GH and IGF-I were mitogenic for chondrocytes and SaOS-2 cells, as indicated by the dose-related increase in uptake of [3H]thymidine. PTH(1-34) was also mitogenic, while 1,25(OH)2D3 inhibited the proliferation of both chondrocytes and SaOS-2 cells in a dose-dependent manner. 17 beta-oestradiol was stimulatory in SaOS-2 cells, but gave a biphasic pattern in chondrocytes; it was stimulatory at low concentrations (0.1 nmol/l) and inhibitory at supraphysiological doses (10 nmol/l). Using the cDNA polymerase chain reaction, specific mRNAs for IL-1 beta, IL-6, IL-8 and TGF-beta were found in chondrocytes, while SaOS-2 cells had a positive signal only for TGF-beta. Specific enzyme immunoassays revealed detectable levels of IL-1 beta, IL-6 and IL-8 only in chondrocytes. IL-6 was increased by GH and IGF-I, and lowered by 1,25(OH)2D3 and supraphysiological doses of 17 beta-oestradiol, while PTH(1-34) had no effects. IL-8 was not influenced by GH or IGF-I, was slightly but not significantly increased by PTH(1-34) and was reduced by 1,25(OH)2D3 and 17 beta-oestradiol at supraphysiological doses.(ABSTRACT TRUNCATED AT 250 WORDS)