Dynamic responses to leptin secretagogues in lean, obese, and massively obese men and women.
OBJECTIVE
Basal plasma leptin levels are higher in women than in men and also higher in obese than in lean subjects, but the dynamic leptin secretion has not been well studied. We tested whether the leptin secretory response to glucocorticoid or insulin differs by gender and adiposity status.


METHODS
Seventy-nine nondiabetic adults, comprising lean [body mass index (BMI; kg/m(2)) < or =25; n = 27], obese (BMI 30-40; n = 28), and massively obese (BMI >40; n = 24) subjects, participated in two separate studies. In study 1, the subjects received oral dexamethasone (4 mg), with blood sampling before and 8 and 16 h after ingestion. In study 2, the subjects underwent a two-step hyperinsulinemic (1.0 mU.kg(-1)/min for 3 h, then 2.0 mU.kg(-1)/min for 3 h), euglycemic (approximately 100 mg/dl) clamp. Blood samples were obtained at baseline and every 20 min during the clamp.


RESULTS
Basal and stimulated leptin levels were higher in women than in men, and higher in the obese groups than in lean subjects. The percentage increase above baseline leptin was similar among men and women within each group, but was approximately 30% lower in massively obese compared to lean subjects.


CONCLUSIONS
Leptin secretory responses to glucocorticoid or insulin stimulation are preserved across a broad adiposity range, with higher absolute responses in women than in men.
Dagogo-Jack
Samuel
S
Department of Medicine and General Clinical Research Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA. sdj@utmem.edu
Askari
Hasan
H
Tykodi
Gunjan
G
Liu
Jianmei
J
Umamaheswaran
Indira
I
D000328:Adult; D002097:C-Reactive Protein / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D015309:Glucose Clamp Technique; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D020738:Leptin / Q000097:blood / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000097:blood*; D009767:Obesity, Morbid / Q000097:blood; D012636:Secretory Rate / Q000187:drug effects; D012737:Sex Factors
D005938:Glucocorticoids; D007004:Hypoglycemic Agents; D007328:Insulin; D020738:Leptin; D003907:Dexamethasone; D002097:C-Reactive Protein; D006854:Hydrocortisone