Cross-sectional study of factors influencing sex hormone-binding globulin concentrations in normally cycling premenopausal women

Serum visfatin concentration and its relationship with sex hormones in obese Saudi women

OBJECTIVE

Visfatin is an adipokine secreted mainly by adipose tissue and has been implicated in obesity. It also mimics the effects of insulin and its expression is hormonally regulated by hormones. Serum visfatin concentrations were evaluated in Saudi women of different body weights to determine its relationships with sex hormones and obesity-induced insulin resistance (IR) in women in Saudi Arabia.

METHODS

In this cross-sectional study, 83 healthy Saudi women of different body weights were recruited between 2014 and 2016, from King Abdulaziz University staff and students. They were divided into three groups according to their body mass indexes (BMIs). Anthropometric measurements were recorded for all of the participants. Blood samples were collected to assess the biochemical variables, including glucose, insulin, lipid profile, visfatin, sex hormone-binding globulin (SHBG), and sex hormones levels.

RESULTS

Obese women exhibited significantly higher blood pressure (BP), glucose, insulin, IR, lipid profile, and visfatin levels than overweight and lean women. However, lean women had significantly higher high-density lipoprotein-cholesterol (HDL)-C, estradiol (E2), luteinizing hormone (LH), and SHBG levels than overweight and obese women. Positive correlations were observed between visfatin levels and waist and hip circumferences, BMI, diastolic BP, systolic BP (SBP) insulin, IR, and LDL-C levels (P < 0.001 - P < 0.05). Negative correlations were observed between visfatin levels and HDL-C, SHBG, LH, and E2 levels (P < 0.001 - P < 0.05).

CONCLUSIONS

The results of this study revealed that E2 and SHBG concentrations were decreased in obese women, while visfatin levels were increased in obese women with high IR levels. This suggests that visfatin levels and sex hormones interact synergistically with obesity with regard to the IR risk in obese women.

Obesity, Leptin and Breast Cancer: Epidemiological Evidence and Proposed Mechanisms

The prevalence of obesity has been steadily increasing over the past few decades in several developed and developing countries, with resultant hazardous health implications. Substantial epidemiological evidence has shown that excessive adiposity strongly influences risk, prognosis, and progression of various malignancies, including breast cancer. Indeed, it is now well recognized that obesity is a complex physiologic state associated with multiple molecular changes capable of modulating the behavior of breast tumor cells as well of the surrounding microenvironment. Particularly, insulin resistance, hyperactivation of insulin-like growth factor pathways, and increased levels of estrogen due to aromatization by the adipose tissue, inflammatory cytokines, and adipokines contribute to breast cancerogenesis. Among adipokines, leptin, whose circulating levels increase proportionally to total adipose tissue mass, has been identified as a key member of the molecular network in obesity. This review summarizes the current knowledge on the epidemiological link existing between obesity and breast cancer and outlines the molecular mechanisms underlying this connection. The multifaceted role of the obesity adipokine leptin in this respect is also discussed.

Sex Hormone Decline and Amyloid β Synthesis, Transport and Clearance in the Brain

Sex hormones (SH) are essential regulators of the central nervous system. The decline in SH levels along with ageing may contribute to compromised neuroprotection and set the grounds for neurodegeneration and cognitive impairments. In Alzheimer's disease, besides other pathological features, there is an imbalance between amyloid β (Aβ) production and clearance, leading to its accumulation in the brain of older subjects. Aβ accumulation is a primary cause for brain inflammation and degeneration, as well as concomitant cognitive decline. There is mounting evidence that SH modulate Aβ production, transport and clearance. Importantly, SH regulate most of the molecules involved in the amyloidogenic pathway, their transport across brain barriers for elimination, and their degradation in the brain interstitial fluid. This review brings together data on the regulation of Aβ production, metabolism, degradation and clearance by SH.