ABSTRACT
OBJECTIVE: We investigated the effect of intermittent food restriction (IFR) cycles on hypothalamic expression of lipogenic proteins and induction of overeating. METHODS: Female Wistar rats were distributed in three groups: free access to feed (control, C), 2 d feed restriction at 50% of C intake followed by 3 d (restricted 3, R3) or 5 d (restricted 5, R5) ad libitum feeding. After 6 wk, the rats were submitted to euthanasia and collected the hypothalamus and blood. The deposits of retroperitoneal, mesenteric, and gonadal fat were weighed. The expression of the mRNA for sterol regulatory element binding protein (SREBP) 1c and 2 and acetyl-CoA carboxylase in the hypothalamus were determined by real-time polymerase chain reaction, and glucose and triacylglycerol were evaluated by a commercial kit. Body mass and food intake were measured daily. RESULTS: IFR promoted increased expression of SREBP-2 in both treated groups and, in R5, increased expression of SREBP-1c. The serum triacylglycerol, mesenteric deposit, and total fat content were higher in R3. Neither of the treatment intervals altered the expression of the mRNA of acetyl-CoA carboxylase enzyme but induced hyperglycemia and higher food intake immediately after food restriction. CONCLUSION: IFR affected the expression of SREBP-1c in R5 and SREBP-2 in the hypothalamus and caused overeating immediately after fasting in both groups. We suggest that hypothalamic and peripheral alterations, coupled with compulsive eating behavior in the ad libitum period, indicate risks for diabetes mellitus and recovery of body mass after interruption of IFR.
Subject(s)
Caloric Restriction/adverse effects , Eating/genetics , Fasting/adverse effects , Hyperphagia/metabolism , Sterol Regulatory Element Binding Proteins/metabolism , Acetyl-CoA Carboxylase/metabolism , Animals , Female , Hyperphagia/etiology , Hypothalamus/metabolism , RNA, Messenger/metabolism , Rats , Rats, WistarABSTRACT
La práctica de restricción alimentaria intermitente (RAI) bien como sus variaciones, es utilizada por individuos con intensión de pérdida de masa corporal. Existen evidencias científicas favorables a esta práctica; no obstante, son insuficientes los estudios que muestren las consecuencias a largo plazo y sus repercusiones en el control de la homeostasis energética en el sistema nervioso central (SNC). Considerando su creciente utilización, tanto como su recomendación y además de la controversia existente en la bibliografía, la presente revisión tiene como objetivo mostrar los efectos de la RAI sobre la regulación central de la homeostasis energética registrados en la literatura.
The practice of intermittent food restriction (IFR) along its variations, is used by individuals with an intentional loss of body mass. There is scientific evidence favorable to this practice; however, studies showing the long term consequences and their impact on the control of energy homeostasis at the level of the central nervous system (CNS) are insufficient. Considering the increase in its use, as well as in its recommendation and the great controversy existing in the bibliography, the present review aims to show the effects of RAI on the central regulation of energy homeostasis reported in the literature.