Abstract
As men age, serum testosterone (T) levels decline, whereas serum luteinizing hormone (LH) levels increase somewhat or remain unchanged. Age-related reductions in T levels may be associated with alterations in body composition; energy level; muscle strength; physical, sexual, and cognitive functions; and mood. The predominant contributor to the decline in serum T levels is the decreased ability of the aging testes to make T. As in humans, the Brown Norway rat demonstrates age-related reductions in serum T levels in the setting of unchanged or modestly increased serum LH levels. In this rat model, the ability of aged Leydig cells, the terminally differentiated T-producing cells of the testis, to produce T in response to LH stimulation is significantly diminished. This review begins with a discussion of what is known of the molecular mechanisms by which T synthesis declines with Leydig cell aging. It concludes with a brief history of T replacement therapy, current guidelines, controversies related to T replacement therapy in older men, and proposed future clinical directions.
Original language | English (US) |
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Pages (from-to) | 1111-1118 |
Number of pages | 8 |
Journal | Journal of andrology |
Volume | 33 |
Issue number | 6 |
DOIs | |
State | Published - 2012 |
Externally published | Yes |
Keywords
- Hypogonadism
- Leydig cells
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Reproductive Medicine
- Endocrinology
- Urology