Hormonal Regulation of Aging

Aging involves a decline of GH, which causes the immune system response to decline and the amount of oxygen and free radicals to increase. The skin suffers from the consequences of the decline in GH, which is reduced nourishment and repair of cells in the different tissues. The overall functions of the skin decrease with aging. The decline is noted in cell replacement, sensory perception, thermal regulation, and chemical clearance. Also, there is a higher threshold for pain, predisposing to skin irritations, ulcerations, and wounds [8].

Additional changes of skin aging include flattening of the dermal–epidermal junction, which decreases the contact surface between the dermis and epidermis. This change may compromise communication and nutrient transfer between skin layers.There is a decrease in epidermal filaggrin, a protein required to bind keratin filaments into macrofibrils, that contributes to skin dryness and flaking. In addition, there is an increased dermal separation that may cause increased blistering or tearing.

The endocrine system regulates body composition, fat deposition, skeletal mass, muscle strength, metabolism, body weight, and physical well-being. Multiple endocrine changes evolve with aging in all species and,not surprisingly, some of the physiologic manifestations of aging are related to the effects of declining hormone levels. The central nervous system (CNS) regulates the pituitary gland, which secretes hormones to target tissues that, in turn, produce substances that feed back on the hypothalamic– pituitary axis. This feedback-control network can be assessed via novel entropy statistics.

In humans, aging is associated with a decrease in the gonadal production of estrogen in females (menopause) and testosterone in males (andropause), the adrenal production of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S) (adrenopause), and a decrease in the activity of the GH/insulin-like growth factor (IGF) axis (somatopause). Replacing hormones that decline with age had been shown to have a broad anti-aging and anti-disease effect on the skin and in the body. As a result, hormone replacement regimens are being developed as a strategy to delay or prevent some of the consequences of aging.