Clinical Hypogonadism and Androgen Replacement Therapy: An Overview

Dana A. Ohl; Susanne A. Quallich


Urol Nurs. 2006;26(4):253-259,269. 

In This Article

Testosterone Deficiency: Hypogonadism

Testosterone deficiency, hypogonadism, may be categorized as primary, secondary, or combined (see Table 3 ). Some conditions responsible for hypo gonadism, such as obesity or the feedback inhibition seen in chronic alcoholism, are re versible. Estimates of the prevalence of hypogonadism in the United States are difficult to compare, as there is disagreement regarding the definition and laboratory values that determine hypogonadism. Esti mates from data in the Massachusetts Male Aging Study (MMAS) estimated 2.4 million men aged 40 to 69 had some degree of hypogonadism (Araujo et al., 2004). Other studies estimate the prevalence of age-related hypogonadism due to all causes at 20% to 30% (Allan & McLahan, 2004).

The presentation of clinical hypogonadism will vary, but there is an acknowledged decline in testosterone levels as men age. At age 75, the mean total testosterone level is roughly two-thirds of the mean for 20 to 30-year-old men, while the free testosterone is only 40% that of the younger men (Vermeulen, 2001). There is an insidious onset and slow progression of the decline of testosterone, with many of the symptoms attributed to existing co-morbidities in an individual. There is also significant individual variability as to onset and speed of decline of testosterone levels. Individuals may complain of hypogonadal symptoms at differing ages and to differing degrees. Complaints such as fatigue or loss of muscle mass may be seen as part of normal aging, meaning that the hypogonadism seen with advancing age is likely to be both under-recognized and under-treated.

It is difficult to discuss hypogonadism in the aging male as a singular entity. With age, the responsiveness of the pituitary gland to hormonal signals declines, and there is a gradual desensitization and decline in number of the Leydig cells (testicular failure). LH secretion becomes erratic, further disrupting the signaling system and leading to a decline in available testosterone. Growth hormone deceases with age, contributing to the decline in lean muscle mass and bone density. Dehydro epiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) also decline with age, and may impact the psychological and well-being aspect of aging.


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