Table 3 Physiological role of hormones
Men | Women | Both sexes | Obesity/type 2 diabetes | |
|---|---|---|---|---|
Estradiol | Estradiol in men is essential for modulating libido, erectile function, and spermatogenesis [140] A study conducted in healthy men suggests that estradiol protects from NAFLD [141] | Endogenous estrogens are master regulators of lipid metabolism and inhibit inflammation, vascular cell growth, and plaque progression in premenopausal women [142] The loss of estrogens which occurs postmenopausally is associated with a modest increase in LDL cholesterol with either no change or a small decrease in HDL cholesterol. Estrogen administration decreases LDL cholesterol and Lp(a) levels while increasing triglycerides and HDL cholesterol levels, but these effects are dependent on the dose and route of administration [143] | Estrogens improve inflammation related to metabolic dysfunction (“metaflammation”). Further to a direct downregulation of inflammatory pathways, this effect is also mediated by metabolic amelioration [144] | Obesity is associated with hyperestrogenism which, in turn, increases the risk of breast cancer in men [145] |
Progesterone | Progesterone has important effects in regulating male fertility by affecting the energetic homeostasis of sperm [146] | Progesterone has a major role in the ovarian and menstrual cycle; moreover it exerts an immuno regulatory function; regulates the contraction of human intestinal smooth muscle cells and the motility of various human cell types [147] Progesterone is an independent predictor of insulin resistance in girls [148] | Progesterone has been potentially implicated as a therapeutic adjunct in many clinical conditions such as traumatic brain injury, Alzheimer’s disease, and diabetic neuropathy [147] | Increasing levels of progesterone have been associated with the development of systemic insulin resistance [149] Little is known regarding the role, if any, of serum progesterone in NAFLD |
Androgens | The synthesis of testosterone is key to male fertility. A negative feedback finely regulates the secretion of hormones at the levels of hypothalamic-pituitary–gonadal axis. Congenital or acquired disturbances of this axis will lead to hypogonadism and thus impair male fertility [150]. Testosterone has no significant correlation with NAFLD in a study from China [141]. However, it is an independent predictor of insulin resistance in boys [148] | Androgens have important biological roles in young women, influencing bone and muscle mass, vascular health, cognition, mood, well-being, and libido [151] However, testosterone deficiency in young women may pass underdiagnosed because of generally nonspecific symptoms and inaccuracy of testosterone measurement [152]. The primary indication for the prescription of testosterone for women is loss of libido [153] | Sarcopenia, namely the decline in muscle mass and strength which occurs with ageing, has been associated with a deficiency in both 17β-estradiol and testosterone, two sex hormones which act on satellite cells. These remain quiescent throughout life and are activated in response to stressful events, enabling them to guide repair and regeneration of the skeletal muscle [154] | Obese men tend to be hypogonadic as a result of the functional suppression of the hypothalamic–pituitary–testicular axis [155]. However, weight loss obtained with either a low-calorie diet or bariatric surgery is associated with the normalization of sex hormone levels exhibiting a significant increase in bound and unbound testosterone and gonadotropin levels and a decrease in estradiol [156]. A study from Japan reported that testosterone levels were inversely associated with diabetes among men but not among women [157] |