Osteoclasts are not the major source of interleukin-6 in mouse parietal bones.
Interleukin-6 (IL-6) is produced by bone cells and has been shown to stimulate the proliferation of osteoclast progenitors. Which cells in bone produce IL-6 is controversial. This article tests the hypothesis that tartrate-resistant acid phosphatase-positive osteoclasts (TRAP + OC) in neonatal mouse parietal bones are the major source of IL-6. Bones were preincubated with indomethacin to decrease the number of TRAP + OC and the amount of IL-6 produced. Incubation with parathyroid hormone or prostaglandin E2 increased the number of TRAP + OC and the amount of IL-6 produced. Calcitonin and 17 beta-estradiol inhibited this increase in TRAP + OC but had no effect on IL-6 production. 1,25-dihydroxy-vitamin D3 also stimulated an increase in TRAP + OC number but did not cause increased IL-6 production. Both the endocranial and ectocranial membranes of these bones produced large amounts of IL-6. TRAP activity in extracts of endocranial membranes was 14-fold that of the ectocranial membrane and, histochemically, some TRAP + cells could be detected here. However, the ectocranial membranes produced more IL-6 than the endocranial membranes. We conclude that TRAP + OC are not a major source of IL-6 in this system.
Holt
I
I
Charles Salt Research Centre, Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, UK.
Davie
M W
MW
Marshall
M J
MJ
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002116:Calcitonin / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D006825:Hybridomas; D007213:Indomethacin / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D008808:Mice, Inbred CBA; D009924:Organ Culture Techniques; D010010:Osteoclasts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D010120:Oxytocics / Q000494:pharmacology; D010281:Parathyroid Hormone / Q000494:pharmacology; D010294:Parietal Bone / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase
D016861:Cyclooxygenase Inhibitors; D015850:Interleukin-6; D007527:Isoenzymes; D010120:Oxytocics; D010281:Parathyroid Hormone; D004958:Estradiol; D002116:Calcitonin; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase; D002117:Calcitriol; D015232:Dinoprostone; D002118:Calcium; D007213:Indomethacin