Endocrinological aspects of aging in men: is hormone replacement of benefit?

doi:10.1016/S0301-2115(00)00420-6

European Journal of Obstetrics & Gynecology and Reproductive Biology

Volume 92, Issue 1, September 2000, Pages 7-12

https://doi.org/10.1016/S0301-2115(00)00420-6 Get rights and content

Abstract

Age-related decreases of serum testosterone (total, free and bioavailable), DHEA, DHEA-S, growth hormone (GH) and IGF-I are well established in elderly healthy men. Although substantial, the decrease of these hormones is small compared to the estrogen changes observed in postmenopausal women. Elderly men also loose bone and muscle, gain fat and have less sexual appetite. Therefore, the assumption that hormonal therapy is a potential ‘fountain of youth’ appears logical.

At present, however, the effects of replacement of testosterone, DHEA and GH in healthy elderly men have been studied in only a few randomised placebo-controlled trials. These studies were small and of short duration. Although some significant overall effects of either androgen or GH replacement on body composition (less fat and more muscle) were found, the effects of such therapy on muscle strength, on metabolic and sexual function and on skeletal homeostasis have been less consistent. Also, the safety of such therapy should be better documented. Moreover, data obtained in healthy elderly men cannot be transposed to non-healthy elderly men.

In conclusion, more scientific work is needed before general replacement of the ‘falling hormones’ should be regarded as beneficial for elderly men.

Introduction

In this review article, age-related endocrinological changes in elderly men are discussed. Particularly, changes in androgens (both gonadal and adrenal androgens) and in the growth hormone — insulin like growth factor 1 axis are described. Secondly, we focus on possible effects of these endocrine changes on target organs. Finally, we report on the randomized placebo-controlled studies which have evaluated possible beneficial effects of hormone replacement therapy on endocrine target organs in elderly men.

Section snippets

The gonadal axis

The most important gonadal androgen in man is testosterone (T), which is produced predominantly (95%) by the testicular Leydig cells. Testosterone can be aromatized locally in many tissues into oestradiol or can be transformed into 5 alpha-dihydrotestosterone (5 DHT), which is the active hormone in the prostate gland. The gonadotropins (FSH and LH), of which LH is responsible for the stimulation of the T secretion, are released by the anterior pituitary. The pituitary LH secretion is regulated

Age-associated changes in the target organs

Men typically experience an age-related decrease of lean body mass (LBM) [31]. LBM can be defined as the total mass of all organs of the body, after excluding adipose tissue. Therefore, the LBM consists of extracellular fluid, intracellular compartment and bone mass. The greatest part of the decrease in LBM, however, is explained by loss of muscle. An 80-year old man typically has lost about 50% of his maximal muscular mass [32]. Atrophy of an organ may lead to loss of functional capacity: a

Testosterone replacement therapy

Most studies report effects of testosterone replacement therapy administered to a selected group of so-called healthy, relatively hypogonadal (defined as bioavailable T levels lower than the normal range for young men) elderly men. Therefore, the result of these studies cannot be transposed to frail elderly men, who are frankly hypogonadal or have associated systemic illness.

Conclusion

Although hormone replacement in elderly men has some effects on target organs, the overall benefit of this ‘therapy’ is unclear at present. Moreover, long-term studies with more subjects are needed to prove its beneficial effect and to guarantee its safety. Finally, it is also necessary to obtain information about the potential benefit of hormone replacement in the ‘more typical’ elderly men who are likely to suffer from several concomitant diseases and take several medications.

Acknowledgements

Dirk Vanderschueren is senior clinical investigator of the Flemish fund of scientific research.

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Endocrinological aspects of aging in men: is hormone replacement of benefit?

Abstract

Introduction

Section snippets

The gonadal axis

Age-associated changes in the target organs

Testosterone replacement therapy

Conclusion

Acknowledgements

Mol. Cell Endocrinol.

J. Clin. Epidemiol.

Steroids

Ann. Epidemiol.

Baillières Clin. Endocrinol. Metab.

Metabolism

Bone

J. Urol.

J. Urol.

The aging male reproductive system

Endocrinol. Metab. Clin. North Am.

Influence of some biological indexes on sex hormone binding Globulin and androgen levels in aging or obese males

J. Clin. Endocrinol. Metab.

Clinical review 24. Androgens in the aging male

J. Clin. Endocrinol. Metab.

Testosterone and the aging male

J. Androl.

Loss of circadian rhythmicity in blood testosterone levels with aging in normal men

J. Clin. Endocrinol. Metab.

Age, disease, and changing sex hormone levels in middle-aged men: results of the Massachusetts male aging study

J. Clin. Endocrinol. Metab.

Relationship between serum testosterone and sex hormone-binding globulin in adult men with intact or absent gonadal function

Int. J. Androl.

Hormonal changes and sexual function in aging men

J. Clin. Endocrinol. Metab.

Some reflections on the endocrinology of the aging male

Aging male

Reproductive axis suppression in acute illness is related to disease severity

J. Clin. Endocrinol. Metab.

Testosterone replacement in older hypogonadal men: a 12-month randomized controlled trial

J. Clin. Endocrinol. Metab.

Reproductive hormones in aging men. Measurement of sex steroids basal luteinizing hormone, and Leydig cell response to human chorionic gonadotropin

J. Clin. Endocrinol. Metab.

Episodic luteinizing hormone (LH) secretion and the response of LH and follicle stimulating hormone to LH-releasing hormone in aged men. Evidence for coexistent primary testicular insufficiency and impairment in gonadotropin secretion

J. Clin. Endocrinol. Metab.

Leydig cell numbers, daily sperm production and serum gonadotrophin levels in aging men

J. Clin. Endocrinol. Metab.

Testosterone replacement therapy in older adult men. I

J. Androl.

Leydig cell function in normal men: effect of age, lifestyle, residence, diet, and activity

J. Clin. Endocrinol. Metab.