Depot- and sex-specific differences in human leptin mRNA expression: implications for the control of regional fat distribution.
Obese subjects with excess intra-abdominal fat deposition suffer greater adverse metabolic consequences than do similarly overweight subjects with a predominantly subcutaneous distribution of adiposity. Little is known about the factors regulating the regional distribution of body fat. Leptin is a recently characterized protein secreted by adipocytes that appears to provide a long-term hormonal feedback signal regulating fat mass. No systematic evaluation of site-related differences in human adipocyte leptin expression has been reported to date. Levels of leptin mRNA were examined by quantitative reverse transcription-polymerase chain reaction in adipocytes isolated from omental and subcutaneous adipose depots of nonobese and mildly obese individuals undergoing elective surgery. In all individuals studied (n = 24), leptin mRNA levels were higher in subcutaneous than in omental adipocytes (P < 0.0001). In contrast, there were no consistent site-specific differences in the expression of glycerol-3-phosphate dehydrogenase mRNA. The subcutaneous-to-omental ratio of leptin mRNA expression was markedly higher in women (5.5 +/- 1.1-fold) than in men (1.9 +/- 0.2-fold) (P < 0.02). A significant relationship between BMI and leptin mRNA expression was demonstrable in the subcutaneous adipocytes of women (P < 0.006). Thus, leptin mRNA appears to be expressed predominantly by subcutaneous adipocytes, particularly in women. These findings suggest a possible role for leptin in the control of adipose tissue distribution and mass.
Montague
C T
CT
Department of Medicine, University of Cambridge, U.K.
Prins
J B
JB
Sanders
L
L
Digby
J E
JE
O'Rahilly
S
S
D000005:Abdomen; D017667:Adipocytes / Q000378:metabolism*; D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000378:metabolism*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D020738:Leptin; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000235:genetics; D009852:Omentum; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012044:Regression Analysis; D012727:Sex Characteristics; D012867:Skin; D014158:Transcription, Genetic
D020738:Leptin; D012333:RNA, Messenger