BACKGROUND Low concentrations of leptin secondary to low body fat or other modulators are thought to be a key signal whereby an energy deficit suppresses the reproductive axis in exercising women resulting in functional hypothalamic amenorrhea (FHA). The purpose of this study was to first examine leptin concentrations in exercising women with and without FHA to address whether there is a thresh...

Obesity in children is accompanied by increased circulating leptin concentrations. Girls have higher leptin concentrations than boys. The aim of our study was to compare serum leptin levels before and after a five-week weight reduction program and to study the relationship of leptin levels, serum total cholesterol, and androgens (testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulp...

Leptin, a hormone produced by adipocytes, has been shown to affect a number of central functions, such as regulation of the hypothalamo-pituitary-adrenal axis, feeding, and body weight regulation. Because hypothalamic monoamines are intricately involved in the regulation of these functions, we hypothesized that leptin may produce its effects by altering the activity of these neurotransmitters. ...

INTRODUCTION: Leptin the product of the obese gene (ob) is synthesized by adipose tissue and contributes to the regulation of energy homeostasis and food intake. Recently, immunoreactive leptin was reported to be present in human milk. The aim of this study was to determine any possible link between breast milk leptin concentrations and adiposity in exclusively breast-fed infants. METHODS: 130 ...

The present study has examined the short- and long-term effects of growth hormone (GH) treatment on the leptin system and energy expenditure. Thirty male individuals with abdominal obesity were randomised to GH or placebo treatment in a 9-month, double-blind study. The dose of GH was 9.5 microg/kg, administered subcutaneously every evening. Serum leptin concentrations were measured by a human l...

Leptin administration has been shown to increase renal, adrenal, and lumbar sympathetic nerve activity. However, this generalized sympathoexcitatory activity is not always followed by an increase in arterial pressure. The present study tested the hypothesis that leptin induces a release of nitric oxide (NO) that opposes the pressor effect of sympathoexcitation. The effect of intravenous adminis...

OBJECTIVE Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction. Although the role of leptin in the control of reproduction is unclear, it may be involved in the control of ovulation. The aim of this cross-sectional study was to determine the relationship between circulating leptin concentrations, and anthropometric, metabolic and endocrine variables as well as to examine a p...

This study was done to elucidate the relationship between postprandial leptin and obesity, and the possible influence of the circadian rhythm on the dynamic leptin response to an oral fat load (OFLT). In experiment 1, we measured the leptin and insulin responses to an oral fat load in 16 non-diabetic obese subjects and in 16 healthy controls, matched for age and gender. In experiment 2, we meas...

Animal research suggests that leptin may have an important role in the regulation of energy balance. The role of leptin in the progressive involuntary weight loss associated with cancer in humans is of considerable interest. However, such studies are limited. In this study, we compared circulating leptin concentrations in gastrointestinal cancer patients and weight loss (n = 27) with those of h...

Evidence for regulation of circulating leptin by insulin is conflicting. Diabetes was induced in rats with streptozotocin (STZ; 40 mg ⋅ kg-1 ⋅ day-1× 2 days) to examine the effect of insulin-deficient diabetes and insulin treatment on circulating leptin. After 12 wk, plasma leptin concentrations in untreated rats were all <0.4 ng/ml versus 4.9 ± 0.9 ng/ml in control animals ( P < 0.005). In rat...