Effects of growth hormone treatment on serum levels of insulin-like growth factors (IGFs) and IGF binding proteins 1-4 in postmenopausal women.
OBJECTIVE
Insulin-like growth factor binding proteins (IGFBPs) modulate the actions and bioavailability of insulin-like growth factors (IGFs), however, their regulation in vivo is incompletely understood. In this study we investigated the effects of different doses of growth hormone (GH) on circulating levels of IGFs and IGFBPs.


METHODS
The study was double-blind and placebo-controlled. Patients were treated with either GH in doses of 0.05, 0.10, or 0.20 lU/kg/day of placebo for one week.


METHODS
Forty post-menopausal women aged 52-73 years with low bone mass.


METHODS
Serum IGF-I and IGF-II were measured by RIA while IGFBP-1-3 were measured by Western ligand blot (WLB) and compared with determinations by specific immunoassays. IGFBP-4 was measured by WLB alone.


RESULTS
Both IGF-I (P < 0.001) and IGF-II (P < 0.01) increased significantly during GH treatment. Additionally, IGFBP-1 (P < 0.001) and IGFBP-2 (P < 0.001) decreased significantly while IGFBP-3 (P < 0.001) and IGFBP-4 (P < 0.05) increased all in a dose-dependent manner. Stepwise (backwards) multiple regression analyses showed that the changes in IGF-I and IGF-II, and age correlated with the change in serum IGFBP-1. Both GH-dosage, the increase in IGF-II, and body mass index correlated with the decrease in IGFBP-2. Furthermore, the increase in serum IGF-I, IGF-II, and triiodothyronine correlated with the increase in IGFBP-3. Moreover, GH-dosage correlated with the increase in serum IGFBP-4.


CONCLUSIONS
GH significantly increased serum IGF-I, IGF-II, IGFBP-3, and IGFBP-4 and decreased serum IGFBP-1 and IGFBP-2 in post-menopausal women.
Kassem
M
M
Department of Endocrinology and Metabolism, Aarhus University Hospital, Denmark.
Brixen
K
K
Mosekilde
L
L
Blum
W F
WF
Flyvbjerg
A
A
D000368:Aged; D002117:Calcitriol / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D019382:Human Growth Hormone / Q000627:therapeutic use*; D006801:Humans; D007328:Insulin / Q000097:blood; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000517:prevention & control*; D017698:Postmenopause / Q000097:blood*; D012044:Regression Analysis; D013002:Somatomedins / Q000032:analysis / Q000378:metabolism*; D014284:Triiodothyronine / Q000097:blood
D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D014284:Triiodothyronine; D019382:Human Growth Hormone; D002117:Calcitriol