AGE-RELATED DECREASES IN INSULIN-LIKE GROWTH-FACTOR-I AND TRANSFORMING GROWTH-FACTOR-BETA IN FEMORAL CORTICAL BONE FROM BOTH MEN AND WOMEN - IMPLICATIONS FOR BONE LOSS WITH AGING
V. Nicolas et al., AGE-RELATED DECREASES IN INSULIN-LIKE GROWTH-FACTOR-I AND TRANSFORMING GROWTH-FACTOR-BETA IN FEMORAL CORTICAL BONE FROM BOTH MEN AND WOMEN - IMPLICATIONS FOR BONE LOSS WITH AGING, The Journal of clinical endocrinology and metabolism, 78(5), 1994, pp. 1011-1016
We determined the skeletal content of insulin-like growth factor-I (IG
F-I) and transforming growth factor-beta (TGF beta) in human bone as a
function of age, using 66 samples of femoral cortical bone obtained f
rom 46 men and 20 women between the ages of 20-64 yr. We found a linea
r decline in the skeletal content of IGF-I (nanograms per mg protein)
with donor age (r = -0.43; P < 0.001) in the total population. The ske
letal content of TGF beta also decreased with age (i.e. 1/TGF beta us.
age; r = 0.28; P < 0.02) for the total population. We did not observe
any difference in the skeletal growth factor content between male and
female donors. IGF-I content, when analyzed by decade divisions of ag
e, showed a reduction between the 20- to 29-yr-old and the 50- to 59yr
-old subjects (P < 0.02). The loss rate of IGF-I was 1.56 ng/mg protei
n yr, corresponding to a net loss of 60% of skeletal IGF-I between the
ages of 20-60 yr. The loss rate of TGF beta was 0.03 ng/mg protein yr
, corresponding to a net loss of 25% of the skeletal TGF beta between
the ages of 20-60 yr.