The role of gonadotropins, androgens, and insulin in the regulation of circulating leptin levels is obscure. In order to clarify the relationships of these parameters we studied serum leptin levels in 19 healthy control subjects and in 35 hyperandrogenic and hyperinsulinemic patients with polycystic ovary syndrome (PCOS). Serum leptin concentrations did not differ significantly between PCOS pat...

Introduction: Leptin is a critical metabolic signal linking nutrition and reproductive functions. Leptin receptors are expressed in germ cells, Sertoli and Leydig cells. Oxidative stress increases sperm DNA damages. Nitric oxide is a free radical, produced by most cells via Nitric Oxide (NO) synthase and plays stimulatory and inhibitory roles on cells. Physiological concentrations of NO are ess...

Leptin, a protein hormone secreted by fat cells, is best known for its role as an adiposity signal; however, leptin has diverse physiological roles ranging from regulation of feeding behavior and body weight, to effects on reproduction and immune function. Although leptin has been extensively studied in mammals, the identification and function of leptin in birds remains controversial, and studi...

Background: Obesity and insulin resistance refer to a clustering of various medical conditions, with a number of pathological components that contribute to the development of diabetes and cardiovascular disease. Some studies have shown that free testosterone levels are low in obese men and are inversely correlated with the degree of obesity. In addition, leptin levels increases with obesity tha...

OBJECTIVE Exercise training may cause changes in thyroid function. This thyroid response may be due to exercise-induced modulation of energy metabolism but also of the adipocytes endocrine function. In particular, the role of leptin and of circulating soluble leptin receptor (sOB-R) was unexplored. The aim of this study was to assess the relationships between thyroid function, whole body energy...

Regulation of the gene expressions of leptin, insulin receptors and lipogenic enzymes was investigated after refeeding a fat-free diet or a 10 g/100 g corn oil diet to food-deprived rats. Plasma glucose and insulin concentrations began to increase 30 min after the feeding and further increased up until 8 h. In these rats, the expression of leptin mRNA in adipose tissue began to increase signifi...

OBJECTIVE The aim was to study the role of leptin in the development of dementia. METHODS Follow-up of the ALEXANDROS cohorts, with baseline measurements in 2000. From 1,136 available subjects free of dementia at baseline, 667 subjects had frozen baseline blood samples for measuring leptin and soluble leptin receptor (sOB-R). The free leptin index (FLI) was calculated as the ratio of leptin t...

Obesity is associated with leptin resistance as evidenced by hyperleptinemia. Resistance arises from impaired leptin transport across the blood-brain barrier (BBB), defects in leptin receptor signaling, and blockades in downstream neuronal circuitries. The mediator of this resistance is unknown. Here, we show that milk, for which fats are 98% triglycerides, immediately inhibited leptin transpor...