The growth of cultured rabbit articular chondrocytes is stimulated by pituitary growth factors but not by purified human growth hormone or ovine prolactin.
Recent reports describing a direct stimulation by GH of bone and cartilage growth led us to compare the in vitro mitogenic effects of highly purified human GH and PRL and two pituitary-derived growth factors in rabbit articular chondrocytes. These preparations were tested for their ability to promote [3H]thymidine incorporation into growth-arrested monolayer chondrocyte cultures and were also assayed in cell growth experiments. The factors tested included 22,000-dalton and 20,000-dalton human GH ovine PRL, glycosylated ovine PRL, bovine pituitary fibroblast growth factor (bpFGF), and a partially purified pituitary growth factor distinct from bpFGF. We found that no significant mitogenic effect was produced by either of the human GH or PRL preparations. Both of the pituitary-derived growth factors were potent mitogens, with bpFGF active at a final medium concentration of 10 pg/ml. These studies support the large body of evidence that GH has no significant direct in vitro effect on chondrocyte growth. The very potent effects of the pituitary-derived growth factors raise the possibility that their presence in GH preparations may be responsible for the in vitro mitogenic effects attributed to these preparations.
K L
KL
Jones
J F
JF
Villela
U J
UJ
Lewis
D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D013006:Growth Hormone / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D010902:Pituitary Gland / Q000032:analysis*; D011388:Prolactin / Q000031:analogs & derivatives / Q000494:pharmacology*; D011817:Rabbits; D012756:Sheep
D006133:Growth Substances; C043928:prolactin, glycosylated; D005346:Fibroblast Growth Factors; D011388:Prolactin; D013006:Growth Hormone; D004247:DNA