Role of Leptin in the Neuroendocrine and Immune Response to Fasting
Role of Leptin in the Neuroendocrine and Immune Response to Fasting
The purpose of this study will be to determine whether giving leptin (r-metHuLeptin) to a
 person when he or she is fasting will reverse changes in metabolism, and hormone levels, and
 immune function associated with fasting, which decreases leptin levels.
Leptin is a hormone secreted by fat cells under normal conditions and acts in the brain to
 decrease appetite and increase energy use. Leptin levels usually go down with fasting. This
 study will evaluate the secretion of an investigational agent called leptin in lean and
 overweight individuals while fasting and investigate the potential role of leptin as a
 regulator of immune function and mediator of the neuroendocrine response to food deprivation
 in humans. Data derived from these studies will provide insights into the mechanisms
 underlying altered hormone levels and immune function in malnutrition and obesity and thus
 may provide the basis for future therapeutic interventions for obesity.

 Comparison: fed state vs. fasting state vs. fasting + leptin state
Inclusion Criteria:

 -  Healthy lean women (with body mass indices [BMI] < 25 kg/m2)

 -  Overweight otherwise healthy men (with BMI > 27 kg/m2)

 -  Overweight otherwise healthy women (with BMI > 27 kg/m2).

 Exclusion Criteria:

 -  A history of any illness that may affect the concentrations of the hormones to be
 studied, e.g. infectious diseases, renal or hepatic failure, type 1 or type 2 diabetes
 mellitus, cancer or lymphoma, hypogonadism, malabsorption or malnourishment, hypo- or
 hyperthyroidism, hypercortisolism, alcoholism or drug abuse, anemia, or eating
 disorder

 -  On medications known to affect the hormones to be measured (glucocorticoids,
 anti-seizure medications, and thyroid hormones)

 -  A known history of anaphylaxis or anaphylactoid-like reactions, or a known
 hypersensitivity to E. coli derived proteins