Dietary (n-3) polyunsaturated fatty acids up-regulate plasma leptin in insulin-resistant rats.
The study was designed to evaluate the chronic regulation of plasma leptin by dietary (n-3) polyunsaturated fatty acids (PUFA) in insulin-resistant, sucrose-fed rats. Male Sprague-Dawley rats were randomly assigned to consume for 3 or 6 wk a diet containing 57.5% (g/100 g) sucrose and 14% lipids as either fish oil (SF) or control oils (SC). After 3 and 6 wk of consuming the SF diet, plasma leptin was 70% (P < 0.001) and 75% (P < 0.05) greater, respectively, than in rats fed the SC diet. The same result was found when plasma leptin was adjusted by total fat mass, as measured by dual-energy X-ray absorptiometry. Despite high leptin levels, food intake of rats fed the SF diet was greater than in SC-fed rats without any difference in body weight or total fat mass. After 3 wk, accumulated leptin in epididymal and retroperitoneal adipose tissue was higher in the SF-fed rats than in the SC-fed rats. However, after 6 wk, tissue leptin in the SF-fed rats did not differ from that of the SC-fed rats. The SF diet increased adipose tissue glucose transporter-4 protein quantity and prevented the sucrose-induced elevations in plasma triglycerides and free fatty acids. When all SC- and SF-fed rats (both diets and feeding durations) were considered, plasma leptin levels were positively correlated with body weight (r = 0.5, P < 0.0001) and with total fat mass (r = 0.5, P < 0.0005). These results suggest that plasma leptin at a given time could be inappropriately high for a given fat mass in insulin-sensitive rats fed (n-3) PUFA.
Peyron-Caso
Elodie
E
Department of Diabetes-INSERM U341, Hôtel-Dieu Hospital, 75181 Paris Cedex 04, France.
Taverna
Mariano
M
Guerre-Millo
Michèle
M
Véronèse
Annie
A
Pacher
Nathalie
N
Slama
Gérard
G
Rizkalla
Salwa W
SW
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D019422:Dietary Sucrose / Q000494:pharmacology; D002149:Energy Intake; D004822:Epididymis; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D020738:Leptin / Q000097:blood*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013395:Sucrose / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D004042:Dietary Fats, Unsaturated; D019422:Dietary Sucrose; D005230:Fatty Acids, Nonesterified; D015525:Fatty Acids, Omega-3; D007328:Insulin; D020738:Leptin; D014280:Triglycerides; D013395:Sucrose