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ANDROGENS AND BONE

Prof. Richard Eastell,

Professor of Bone Metabolism and Research Dean,

Sheffield Medical School, Sheffield, UK.

There has been a change in our ideas about androgens and bone in the last few years. It was thought that the increase in testosterone in boys at puberty was essential to the pubertal growth spurt and to the fusion of the epiphysis. However, it has become clear that the closure of the growth plate is mediated by oestrogen. This observation was made based on genetic disorders - a man with absent oestrogen receptor, and men with absence of the aromatase enzyme were found to have open growth plates and be tall. It is now apparent that the key role of androgens during growth is to promote growth at the periosteum and hence result in larger bones in men than women.

The decline in free testosterone was also felt to be important in the age related loss of bone in men. Again, it appears that the bone loss relates more closely to the decline in oestradiol than in testosterone. The action of testosterone appears to be a small anabolic effect on bone, whereas oestradiol has an antiresorptive effect. When testosterone is given to a hypogonadal man, the most striking effect is the decrease in bone resorption, and this is most likely mediated by the conversion of androgens to oestrogens by aromatase.

Professor Richard Eastell, MD, FRCP (UK, Edinburgh, Ireland), FRCPath,FMedSci
Research Dean for the School of Medicine and Biomedical Science
Director of Research and Development for the Sheffield Teaching Hospitals Trust
Director of the Division of Clinical Sciences (North)
University of Sheffield Clinical Sciences Centre
Northern General Hospital, Herries Road, Sheffield South Yorkshire S5 7AU UK
E-mail r.eastell@sheffield.ac.uk

Recent Publications:

1.         Leder BZ, LeBlanc KM, Schoenfeld DA, Eastell R, Finkelstein JS. Differential effects of androgens and estrogens on bone turnover in normal men. J Clin Endocrinol.Metab 2003;88:204-10.

            2.             Clowes JA, Peel N, Eastell R. Glucocorticoid-induced osteoporosis. Curr.Opin.Rheumatol. 2001;13:326-32.

            3.             Rogers A, Hannon RA, Eastell R. Biochemical markers as predictors of rates of bone loss after menopause. J Bone Miner.Res. 2000;15:1398-404.

            4.             Delmas PD, Eastell R, Garnero P, Seibel MJ, Stepan J. The use of biochemical markers of bone turnover in osteoporosis. Committee of Scientific Advisors of the International Osteoporosis Foundation. Osteoporos.Int 2000;11 Suppl 6:S2-17.

            5.             Eastell R,.Peel N. Rate of Loss Recalculated. J Bone Miner.Res. 1999;14:1991.

            6.             Fatayerji D,.Eastell R. Age-related changes in bone turnover in men. J.Bone Miner.Res. 1999;14:1203-10.