Effects of Age on Testicular Function

Tsitouras, Panayiotis D.

doi:10.1016/s0889-8529(18)30458-4

Cited by 32 publications

(19 citation statements)

References 54 publications

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“…Despite the pronounced discrepancies among the results and interpretations of hormone studies on endocrine testicular function in old age (Nieschlag et al, 1983;Tsitouras, 1987;Vermeulen, 1988), a correlation Figure 34 showing the characteristic " t r i a d formed by the plasma membranes of two adjacent Sertoli cells (small arrow), subplasmalemmal smooth endoplasmic reticulum cisternae (large arrows), and actin filaments (arrowhead). x 16,500. between the hormonal pattern and histological testicular pattern has been reported in aging men (Paniagua et al, 198713).…”

Section: Development Of Testicular Atrophymentioning

confidence: 99%

Ultrastructure of the aging human testis

Paniagua

Nistal²,

Sáez³

et al. 1991

J. Elec. Microsc. Tech.

124

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The ultrastructure of the progressive testicular involution with advancing age in men is reviewed. There is no definite age at which testicular involution begins, and the onset and severity of testicular lesions are subjected to pronounced individual variations. Hormone studies also indicate great individual variations, and subtle changes in both the testis and the pituitary develop progressively with age. Testicular size, sperm quality, and numbers of all germ cell types, Sertoli cells, and Leydig cells decrease with age. The volume occupied by the seminiferous tubules decreases, whereas that occupied by the testicular interstitium remains constant. The most frequent histological pattern of the aging testis is a mosaic of different seminiferous tubule lesions, varying from tubules with complete, although reduced, spermatogenesis, to completely sclerosed tubules. The tubules with complete spermatogenesis may show numerous morphological abnormalities in the germ cells, including multinucleation. Abnormal germ cells degenerate causing Sertoli cell vacuolation. These vacuoles correspond to dilations of the extracellular spaces resulting from the premature exfoliation of germ cells. Degenerating cells that are phagocytosed by the Sertoli cells give rise to an accumulation of lipid droplets in the Sertoli cell cytoplasm. The loss of germ cells begins with the spermatids, but progressively affects the earlier germ cell types, and tubules with maturation arrest at the level of the spermatocytes or spermatogonia are observed. The Sertoli cells show morphological abnormalities such as dedifferentiation, mitochondrial metaplasia, and multinucleation. Germ cell loss is associated with thickening of the tunica propria. When all seminiferous epithelial cells have disappeared, only an intensely collagenized tunica propria with myoid cells remains (sclerosed tubules). The Leydig cells progressively dedifferentiate with a decrease in the quantity of both smooth endoplasmic reticulum and mitochondria, together with an accumulation of lipid droplets, crystalline inclusions, and residual bodies, and formation of multinucleate cells. The development of tubular involution with age is similar to that observed after experimental ischemia, suggesting that vascular lesions may play an important role in age-related testicular atrophy.

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Section: Development Of Testicular Atrophymentioning

confidence: 99%

Ultrastructure of the aging human testis

Paniagua

Nistal²,

Sáez³

et al. 1991

J. Elec. Microsc. Tech.

124

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“…The relationships between sex steroid levels and their consequences in aging are likely to be complex. C ONCENTRATIONS OF SEX steroids in serum decline progressively with age in men, apparently as a result of complex alterations in reproductive physiology (1)(2)(3)(4), secondary causes of gonadal dysfunction and lifestyle factors (5,6), and changes in the levels of binding proteins (7). The relative importance of these changes remains controversial, but these modifications in sex steroid levels have been postulated to underlie, at least in part, other biological processes that occur concomitantly with male aging (e.g.…”

mentioning

confidence: 99%

Testosterone and Estradiol among Older Men

Orwoll

Lambert

Marshall

et al. 2006

The Journal of Clinical Endocrinology & Metabolism

289

176

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“…An associated S. 5 I modest elevation in FSH and LH levels occurs. However, levels of total and free testosterone in healthy older men do not usually fall below the range considered normal in young men (Davidson et al, 1982;Tsitouras, 1987).…”

Section: Hormone Cycles and Changes With Agingmentioning

confidence: 87%

Hormones and Epilepsy Through the Lifetime

Morrell

1992

Epilepsia

106

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Hormones influence brain function from gestation throughout life and may affect the seizure threshold by altering neuronal excitability. Estrogen enhances and progesterone diminishes neuronal excitability experimentally, whereas testosterone and corticosteroids have less consistent effects. Hormonal effects in the C N S also depend on the region of brain in which the hormone acts. Sites of action for most steroid hormones include the hypothalamus and limbic cortex, providing a mechanism for modulating behavior and endocrine function. Seizure patterns may change at certain life stages, perhaps as a result of alterations in hormones. At puberty, epilepsy and benign rolandic epilepsy often remit, while juvenile myoclonic and photosensitive epilepsy may arise. Other types of epilepsy do not respond predictably to events in the reproductive life or to advancing age. In some women, fluctuations in hormones over the menstrual cycle appear to increase seizure vulnerability, probably reflecting changes in relative amounts of estrogen and progesterone. Seizure patterns can be altered, for better or worse, during pregnancy. Whether this reflects the effects of hormones or changes in levels of antiepileptic drugs is not resolved. More information is needed about changes in established epilepsy at menopause and in the elderly. Better understanding of endocrine e 5 m on seizures over a lifetime should lead to more effective epilepsy therapies.

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Effects of Age on Testicular Function

Cited by 32 publications

References 54 publications

Ultrastructure of the aging human testis

Ultrastructure of the aging human testis

Testosterone and Estradiol among Older Men

Hormones and Epilepsy Through the Lifetime

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