Effect of exercise training on adipocyte-size-dependent expression of leptin and adiponectin.
OBJECTIVE
Our aim was to evaluate the effect of exercise training (TR) on adipocyte-size-dependent expression of leptin and adiponectin.


METHODS
Male Wistar rats were divided into 2 groups, sedentary control (CR) and TR group, and both monitored for 9weeks. Adipocytes isolated from epididymal, retroperitoneal, and inguinal fat depots were independently separated into 3 fractions of different cell size, and the relationships between adipocyte size and either leptin or adiponectin mRNA were determined by real-time RT-PCR analysis.


RESULTS
In epididymal and inguinal adipose tissue, positive relationships between adipocyte size and both leptin and adiponectin mRNA expression were found. Comparison of TR and CR rats showed no significant effect of TR on the slopes of the linear regression lines of correlation between leptin mRNA and adipocyte size in either adipose tissue, whereas the slopes of the regression line of correlation between adipocyte size and adiponectin mRNA were greater in TR group. Leptin levels per milliliter of plasma were significantly lower in TR than CR rats, whereas leptin levels adjusted to the 3 fat depots did not differ. TR did not affect adiponectin levels in plasma, whereas adiponectin levels adjusted to the 3 fat depots were significantly greater in TR than CR group.


CONCLUSIONS
TR-induced reduction in leptin mRNA expression was closely associated with smaller adipocyte size. However, TR amplified the adipocyte-size-dependent expression of adiponectin mRNA, suggesting that TR-induced alterations in adiponectin mRNA may also be mediated by factor(s) other than adipocyte size.
Health Promotion Science Group, Department of Human Health Science, Graduate School of Human Health Science, Tokyo Metropolitan University, Hachioji 192-0397, Japan.
Satoko
S
Miyazaki
Tetsuya
T
Izawa
Jun-etsu
JE
Ogasawara
Takuya
T
Sakurai
Sachiko
S
Nomura
Takako
T
Kizaki
Hideki
H
Ohno
Takao
T
Komabayashi
D017667:Adipocytes / Q000378:metabolism*; D052242:Adiponectin / Q000097:blood / Q000378:metabolism*; D000818:Animals; D048429:Cell Size; D005786:Gene Expression Regulation; D020738:Leptin / Q000097:blood / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012420:Running
D052242:Adiponectin; D020738:Leptin; D012333:RNA, Messenger