Paradoxically slow preadipocyte replication and differentiation in corpulent rats.
We have investigated the in vitro rate of replication and differentiation of preadipocytes derived from lean (+/+) and obese (cp/cp) male JCR:LA-corpulent (cp) rats in an attempt to identify mechanisms that regulate adipose tissue growth. Cp/cp rats were twofold heavier than age-matched lean rats by 9-10 mo. Cp/cp-derived preadipocytes demonstrated an inherently slower rate of replication than +/+ preadipocytes (population doubling time: cp/cp 52.3 +/- 9.6 h vs. +/+ 19.7 +/- 1.6 h), although the preadipocyte pool in the cp/cp was significantly greater. Cp/cp preadipocytes were resistant to hormonally induced differentiation (19.9 +/- 9.4% of cells accumulated lipid) but differentiated when cocultured with mature adipocytes to the same extent as preadipocytes derived from Sprague-Dawley (SD) rats (cp/cp 48.4 +/- 15.2% vs. SD 52.2 +/- 11.9%). In contrast, SD preadipocytes did not differentiate in response to mature adipocytes from +/+ rats (13.8 +/- 5.2%). Our observations suggest that preadipocyte replication and maturation may not be controlled in a coordinated manner.
Shillabeer
G
G
Department of Medicine, University of Calgary, Alberta, Canada.
Forden
J M
JM
Russell
J C
JC
Lau
D C
DC
D000273:Adipose Tissue / Q000166:cytology / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D001835:Body Weight; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D007700:Kinetics; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D009929:Organ Size; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013045:Species Specificity