Secondary Hypogonadism in Older Men: Its Relation to Impotence^*

Abstract

The relation of the reproductive endocrine system to impotence in older men was examined by measuring the concentrations of testosterone (T), bioavailable testosterone (BT), LH, and PRL and body mass index (BMI) in 57 young controls (YC), 50 healthy potent older controls attending a health fair (HF), and 267 impotent patients (SD). The SD and HF had markedly reduced mean T and BT values compared to YC. When adjusted for age and BMI there was no difference in BT between potent and impotent older men. The percent BT was much higher in YC than in the older groups. While the percent BT rose significantly with increased T in YC, it was inversely related to T in the older subjects, suggesting that increased sex hormone-binding globulin binding was a primary event leading to a low BT. Forty-eight percent of HF and 39% of SD were hypogonadal, as defined by a mean BT of 2.5 SD or more below the mean of YC (less than or equal to 2.3 nmol/L). Ninety percent of these had LH values in the normal range, suggesting hypothalamic-pituitary dysfunction. Thirty-four SD and six each of YC and older control volunteers (OC) underwent GnRH testing. Older subjects showed impaired responsiveness to GnRH compared to YC. A low basal LH level correlated very highly with hyporesponsiveness to GnRH. Thus, secondary hypogonadism and impotence are two common, independently distributed conditions of older men.

Impact of Aging on Steroid Hormone Biosynthesis and Secretion

“…Although some follow-up studies failed to detect age-related decline in plasma testosterone levels in older men [99][100][101][102][103][104], subsequent population-based cross-sectional and longitudinal studies have confirmed progressive loss of testosterone with aging in healthy men [96,[105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121][122]. Mirroring this decline in plasma testosterone concentration is an age associated increase in sex-hormonebinding globulin (SHBG) level [117], a major plasma carrier of testosterone, resulting in even more dramatic decreases in unbound free testosterone [110,[123][124][125], and weakly bound bioavailable testosterone [126,127]. [In healthy male adults, circulating testosterone exists in three forms: testosterone strongly bound to SHBG, testosterone weakly bound to albumin and free testosterone].…”

Insuficiência androgênica de origem hipotálamo-hipofisária em dois homens com disfunção sexual

“…Já a resposta ao Clomifeno é normal e o seu uso em baixas doses por longo prazo leva à normalização androgênica (5). O conjunto destes achados laboratoriais indica uma possível deficiência na liberação de LHRH (3-5), cuja causa poderia ser qualquer uma das que levam a uma redução dos níveis de testosterona, tais como stress (6,7), abuso de álcool (8), doenças sistêmicas crônicas ou agudas (9), idade avançada e outras (8,10,11).…”

Gonadal function in men with chronic illness

“…There appear to be age related changes in the Leydig cells and elevated LH levels have been found in association with elevated FSH (Nieschlag et al, 1982;Gray et al, 1991) and reduced sperm production . Others have found unchanged LH levels (Zumoff et al, 1982;Korenman et al, 1990) or reduction in LH pulse amplitude (Veldhuis et al, 1992) consistent with hypogonadotropic hypogonadism. Further evidence for declining pituitary function is a reduced and delayed response to gonadotrophin releasing hormone (GnRH) .…”