Circulating levels of insulin-like growth factor-I and -II, and IGF-binding protein-3 in inflammation and after parathyroid hormone infusion.
In order to assess if the anabolic action of PTH is related to changes in circulating levels of insulin-like growth factor-I and -II (IGF-I and -II), and IGF binding protein 3 (IGFBP-3), 24 h of PTH infusion was performed in healthy women and in patients with rheumatoid arthritis (RA), a state where both bone metabolism and PTH secretion is influenced by the inflammatory activity. The patients with RA had lower basal levels of both IGF-I and -II than the healthy controls (P < 0.05). In neither group did the IGFs change after 24 h of PTH administration, while IGFBP-3 was significantly increased in the healthy controls (4600 +/- 1200 to 5750 +/- 2200 micrograms/l, P < 0.05). IGFBP-3 was not affected by PTH infusion in patients with RA when the disease had high activity, but when inflammation had subsided they responded with a similar increase in IGFBP-3 as the control group and basal IGF-I and -II levels were normalised. Since IGFBP-3 can enhance the anabolic action of IGF-I, increased IGFBP-3 levels after PTH infusion may reflect a mechanism by which PTH is anabolic for bone. Inflammation may inhibit bone formation via decreased serum levels of IGFs and blocked IGFBP-3 response to PTH.
Johansson
A G
AG
Department of Internal Medicine, University Hospital, Uppsala, Sweden.
Baylink
D J
DJ
af Ekenstam
E
E
Lindh
E
E
Mohan
S
S
Ljunghall
S
S
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000097:blood; D002352:Carrier Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D007260:Infusion Pumps; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D010281:Parathyroid Hormone; D010446:Peptide Fragments; C035747:parathyroid hormone (1-38); D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D002118:Calcium