Pharmacokinetics of Leptin Administration During Fasting
Pharmacokinetics of Leptin Administration During Fasting
The purpose of this study will be to determine the correct dose of leptin, a natural hormone
 secreted by the fat cells, to give to people when they are fasting and also to determine
 whether giving leptin to a person when he or she is fasting will reverse the changes in
 hormone levels that occur with fasting.
Leptin is a newly-identified hormone secreted by fat cells under normal conditions that acts
 in the brain to decrease appetite and increase long term energy usage. Leptin levels usually
 go down when people are not eating for extended periods of time. Changes in metabolism and
 certain hormone levels also occur with fasting. By studying the pharmacokinetics of leptin
 administration, we can evaluate the changes of leptin levels in response to giving different
 doses of leptin as well as acute changes of other hormones in response to leptin levels.
 Investigations such as this one have important implications for the future therapeutic use of
 leptin, including determining the appropriate dose of leptin to use in future studies
 involving leptin administration.

 Comparison: subjects receiving leptin at 3 different doses in the fed state compared to the
 fasting state
Inclusion Criteria:

 -  healthy men with body mass indices (BMI) <25 kg/m2)

 -  overweight otherwise healthy men with BMI > 27 kg/m2

 -  healthy lean women with BMI<25 kg/m2

 -  overweight otherwise healthy women with BMI > 27 kg/m2

 Exclusion Criteria:

 -  history of any illness that may affect the concentrations of the hormones that will be
 studied (such as anemia, infectious diseases, renal or hepatic failure, diabetes
 mellitus, cancer, lymphoma, hypogonadism, malabsorption or malnourishment, hypo or
 hyperthyroidism, hypercortisolism, alcoholism or drug abuse, eating disorders)

 -  on medications known to affect the hormones to be measured in this study (such as
 glucocorticoids, anti-seizure medications or thyroid hormones)

 -  known history of anaphylaxis or anaphylactoid-like reactions or who have a known
 hypersensitivity to E. Coli derived proteins

 -  women who are breast feeding, pregnant, or wanting to become pregnant during the next
 6 months