TY - JOUR
T1 - The effect of ovariectomy and ovarian steroid treatment on growth hormone and insulin-like growth factor-I in the rat femur
AU - Suliman, Isam A.
AU - K. El-Bakri, Nahid
AU - Adem, Abdu
AU - Mustafa, Amged
AU - Urban Lindgren, J.
N1 - Funding Information:
The authors would like to thank Dr. Mohamed Abdelhadi and Dr. Adli Khalil for their assistance in the surgical procedures. This study was supported by grants from the Karolinska Institute, Stockholm, Sweden.
PY - 2001
Y1 - 2001
N2 - Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are known to play an important role in bone metabolism. The regulation of plasma levels of GH and IGF-I by ovarian steroids is well known, however, their effect on local GH and IGF-I is still unclear. In this study, we investigated the effect of ovariectomy and ovarian steroid treatment on the femur GH and IGF-I levels as well as on bone density in the rat. Nine month-old rats were ovariectomized (OVX) or sham-operated (SHAM) and 9 weeks after the surgery they were treated with daily s.c. injections of either 17β-estradiol (OVX + E), progesterone (OVX + P), or vehicle (OVX + V) for another 10 weeks. GH and IGF-I levels in the femur extracts were measured by specific radioimmunoassay (RIA). Ovariectomy decreased GH and had no effect on IGF-I levels. Estradiol treatment increased femur GH and IGF-I levels compared to SHAM rats. Progesterone restored GH and increased IGF-I levels. Ovariectomy decreased, estrogen restored and progesterone partially restored femur bone density. Our results demonstrate that ovariectomy and ovarian steroids modulate the levels of GH and IGF-I in the bone of aged OVX rats. However, these effects appear to be limited to supraphysiological concentrations of estradiol and progesterone.
AB - Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are known to play an important role in bone metabolism. The regulation of plasma levels of GH and IGF-I by ovarian steroids is well known, however, their effect on local GH and IGF-I is still unclear. In this study, we investigated the effect of ovariectomy and ovarian steroid treatment on the femur GH and IGF-I levels as well as on bone density in the rat. Nine month-old rats were ovariectomized (OVX) or sham-operated (SHAM) and 9 weeks after the surgery they were treated with daily s.c. injections of either 17β-estradiol (OVX + E), progesterone (OVX + P), or vehicle (OVX + V) for another 10 weeks. GH and IGF-I levels in the femur extracts were measured by specific radioimmunoassay (RIA). Ovariectomy decreased GH and had no effect on IGF-I levels. Estradiol treatment increased femur GH and IGF-I levels compared to SHAM rats. Progesterone restored GH and increased IGF-I levels. Ovariectomy decreased, estrogen restored and progesterone partially restored femur bone density. Our results demonstrate that ovariectomy and ovarian steroids modulate the levels of GH and IGF-I in the bone of aged OVX rats. However, these effects appear to be limited to supraphysiological concentrations of estradiol and progesterone.
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U2 - 10.1016/S0736-0266(01)00058-4
DO - 10.1016/S0736-0266(01)00058-4
M3 - Article
C2 - 11780998
AN - SCOPUS:0035217502
SN - 0736-0266
VL - 19
SP - 1008
EP - 1012
JO - Journal of Orthopaedic Research
JF - Journal of Orthopaedic Research
IS - 6
ER -