A. Gürlek and O. Gedik
3. Anderson F.H., Francis R.M., Peaston R.T., Wastell H.J.
Androgen supplementation in eugonadal men with
osteoporosis: effect of six months treatment on mark-
ers of bone formation and resorption.
trations were positively correlated with forearm and
hip BMD but not with spinal BMD. In contrast to
our observations, Drinka et al. (18) failed to demon-
strate a relation between testosterone levels and
BMD at both axial and appendicular sites. Despite
the correlation between BMD and testosterone, we
could not show any association between testos-
terone and bone turnover markers. The only nega-
tive correlation existed between serum free testos-
terone and urinary calcium/creatinine ratio. We
found a negative correlation between age and
DHEAS, but DHEAS had no correlation with BMD
and bone turnover markers. This finding is in ac-
cordance with the observations of Greendale et al.
(15), who were able to demonstrate a positive as-
sociation of DHEAS and BMD in women but not in
men. The role of DHEAS in the maintenance of
male bone mass has received limited investigation.
However, in two studies (19, 20) no association was
found between DHEAS and BMD in men.
J. Bone Miner. Res. 1997, 12: 472-478.
4. Smith E.P., Boyd J., Frank G.R., Takahashi H.,
Cohen R.M., Specker B., Williams T.C., Lubahn
D.B., Korach K.S.
Estrogen resistance caused by a mutation in the es-
trogen-receptor gene in a man.
N. Engl. J. Med. 1994, 331: 1056-1061.
5. Carani C., Qin K., Simoni M., Faustini-Fustini M.,
Serpente S., Boyd J., Korach K.S., Simpson E.R.
Effect of testosterone and oestradiol in a man with
aromatase deficiency.
N. Engl. J. Med. 1997, 337: 91-95.
6. Morishima A., Grumbach M.M., Simpson E.R., Fisher
C., Qin K.
Aromatase deficiency in male and female siblings
caused by a novel mutation and the physiological
role of estrogen.
J. Clin. Endocrinol. Metab. 1995, 80: 3689-3698.
Limitations of the study
7. Gillberg P., Johansson A.G., Ljunghall S.
Decreased oestradiol levels and free androgen in-
dex and elevated sex hormone-binding globulin lev-
els in male idiopathic osteoporosis.
There are two main limitations of this study. Firstly,
the number of subjects is limited (no.=14), and we
would have had lower p values in Spearman rank
correlation tests if we had enrolled more subjects.
Secondly, as in other reported studies, a single de-
termination of sex steroids was made. This intro-
duces a null bias, because sex steroids are not stat-
ic in men and women. For example, testosterone
is converted to estrogen in both men and women.
Thus, it is difficult to judge which hormones are in-
fluencing the skeletal system directly and which are
upstream sources of substrate to form the bone ac-
tive hormones. In conclusion, our data suggest that
serum estradiol and testosterone levels are associ-
ated with BMD in elderly men, possibly indicating
their contribution to skeletal maintenance in old
age. However, further studies with larger number
of subjects are required to assess the interaction of
endogenous sex steroids, GH and IGF-I with bone
metabolism in aging men.
Calcif. Tissue Int. 1999, 64: 209-213.
8. Jones J.I., Clemmons D.R.
Insulin-like growth factors and their binding proteins:
biological actions.
Endocr. Rev. 1995, 16: 3-32.
9. Kurland E.S., Rosen C.J., Cosman F., McMahon D.,
Chan F., Shane E., Lindsay R., Dempster D., Bilezikian
J.P.
Insulin-like growth factor-I in men with idiopathic os-
teoporosis.
J. Clin. Endocrinol. Metab. 1997, 82: 2799-2805.
10. Ljunghall S., Johansson A.G., Burman P., Kampe O.,
Lindh E., Karlsson F.A.
Low plasma levels of insulin-like growth factor I (IGF-
I) in male patients with idiopathic osteoporosis.
J. Intern. Med. 1992, 232: 59-64.
11. Delmas P.D.
Biochemical markers of bone turnover: methodology
and clinical use in osteoporosis.
Am. J. Med. 1991, 91 (Suppl. 5B): 59S-63S.
12. Canalis E., McCarthy T., Centrella M.
Growth factors and the regulation of bone remodeling.
J. Clin. Invest. 1988, 81: 277-281.
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