title: Moderate, selective depletion of linoleate and alpha-linolenate in weight-cycled rats.
abstract: In rats, the response of adipose tissue composition to a single weight cycle (24-48 h of fasting followed by refeeding) is characterized by a decrease primarily in linoleate and alpha-linolenate, with little or no change in other fatty acids. We tested the hypothesis that during successive weight cycles caused by repeated fasting and refeeding, the depletion of linoleate and alpha-linolenate from whole body stores would be exacerbated despite their adequate availability during the refeeding period. Four complete weight cycles (24-h fasting followed by 72-h ad libitum refeeding) induced a significant quantitative decrease in total n-3 and n-6 polyunsaturates, particularly linoleate and alpha-linolenate, and a simultaneous increase in the accumulation of palmitate, palmitoleate, and oleate in carcass total lipids and in perirenal and epididymal adipose tissue. A significant positive relationship was observed between the increasing ratio of saturates+monounsaturates to n-3 + n-6 polyunsaturates in adipose tissue and the number of weight cycles (r = +0.96, P < 0.0001). The percentage of linoleate and alpha-linolenate in adipose tissue was inversely related to the number of weight cycles. We conclude that, despite providing adequate n-6 and n-3 polyunsaturates in the diet during the refeeding period, weight cycling in young growing rats causes a moderate, selective depletion of linoleate and alpha-linolenate from tissue stores.
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Chen
authors.forename: C R
authors.initials: CR
authors.lastname: Menard
authors.forename: S C
authors.initials: SC
authors.lastname: Cunnane
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001769:Blood / Q000378:metabolism; D001835:Body Weight; D005215:Fasting; D005227:Fatty Acids / Q000097:blood / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism*; D008099:Liver / Q000033:anatomy & histology / Q000378:metabolism; D008297:Male; D009929:Organ Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D017962:alpha-Linolenic Acid / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D008041:Linoleic Acids; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid