Regulation of adiponutrin expression by feeding conditions in rats is altered in the obese state.
OBJECTIVE
To characterize the effect of feeding conditions on the expression behavior of adiponutrin, a non-secreted adipose-specific protein proposed to be involved in energy homeostasis maintenance, and its relation with leptin expression in different rat adipose tissue depots under normal and obese conditions.


METHODS
Two rat models were used, Wistar (lean and overweight) and Zucker (lean and obese), submitted to fasting/refeeding. Adiponutrin and leptin expression was determined in different white adipose tissue depots (epididymal, inguinal, mesenteric, and retroperitoneal) and in interscapular brown adipose tissue by reverse transcription-polymerase chain reaction.


RESULTS
We have found site-specific differences in adiponutrin expression in different adipose depots, being the expression pattern close to that of leptin in white adipose tissue. The depot-specific adiponutrin expression is similar in lean and obese animals, except in the inguinal depot, where adiponutrin is overexpressed in obese Zucker. Independently of the degree of expression in the tissue, adiponutrin is an acute sensor of feeding conditions compared with other diet-regulated adipokines, as is leptin. In lean rats, 14-hour fasting greatly decreases adiponutrin mRNA levels in all of the depots studied, whereas 3-hour refeeding allows the recovery of the levels found in control animals. In both overweight Wistar and obese Zucker rats, the decreased mRNA expression observed after fasting in lean rats is not as evident; moreover, in the obese Zucker, there is no recovery after refeeding.


CONCLUSIONS
Adiponutrin expression is highly regulated by feeding conditions in the different adipose tissue depots, but this regulation is impaired in obese rats.
Caimari
Antoni
A
Laboratori de Biologia Molecular, Nutrició i Biotecnologia, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Oliver
Paula
P
Palou
Andreu
A
D052436:Adipose Tissue, White / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D005247:Feeding Behavior / Q000502:physiology*; D005786:Gene Expression Regulation; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009765:Obesity / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011924:Rats, Zucker; D013851:Thinness / Q000235:genetics / Q000378:metabolism
D007328:Insulin; D020738:Leptin; D008565:Membrane Proteins; C436316:adiponutrin