Effect of dietary fatty acid composition on food intake, triglycerides, and hypothalamic peptides

Abstract

While a high-fat diet when compared to low-fat diet is known to produce overeating and health complications, less is known about the effects produced by fat-rich diets differing in their specific composition of fat. This study examined the effects of a high-fat diet containing relatively high levels of saturated compared to unsaturated fatty acids (HiSat) to a high-fat diet with higher levels of unsaturated fatty acids (USat). A HiSat compared to USat meal caused rats to consume more calories in a subsequent chow test meal. The HiSat meal also increased circulating levels of triglycerides (TG) and expression of the orexigenic peptides, galanin (GAL) in the hypothalamic paraventricular nucleus (PVN) and orexin (OX) in the perifornical lateral hypothalamus (PFLH). A similar increase in TG levels and PVN GAL and PFLH OX was also seen in rats given chronic access to the HiSat compared to USat diet, while neuropeptide Y (NPY) and agouti-related protein (AgRP) in the arcuate nucleus showed decreased expression. The importance of TG in producing these changes was supported by the finding that the TG-lowering medication gemfibrozil as compared to vehicle, when peripherally administered before consumption of a HiSat meal, significantly decreased the expression of OX, while increasing the expression of NPY and AgRP. These findings substantiate the importance of the fat composition in a diet, indicating that those rich in saturated compared to unsaturated fatty acids may promote overeating by increasing circulating lipids and specific hypothalamic peptides, GAL and OX, known to preferentially stimulate the consumption of a fat-rich diet.

The regulative effect of galanin family members on link of energy metabolism and reproduction

“…Fourthly, the changes in energy intake, especially as fed with high-fat diet, may influence galanin levels in serum and hypothalamus of animals and humans [12,39,103,100,130]. The galanin levels were positive correlated body mass index [9].…”

“…Firstly, administration of galanin or its agonist, galanin (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), into paraventricular nucleus (PVN) and central nucleus of the amygdala of animals promoted food intake and weight gain when food was plentiful [29,44,92,100,107,151,183].…”

“…These suggest that the effect of alarin on energy metabolism is unlikely to activate the known galanin receptors and seems to be mediated by unknown specific alarin receptors [154]. Recent study displayed that alarin (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), eliminated the first five amino acids from alarin, antagonizes alarin-specific effects on food intake, indicating alarin (6-25) may be an antagonist to alarin-specific receptor [51]. To date, the research about the physiologic and pharmacologic characters of alarin receptor is still insufficient.…”

Deleterious effects of lard-enriched diet on tissues fatty acids composition and hypothalamic insulin actions

“…Previous studies have shown rats treated with high fat diets showed increased body fat content and decreased food intake (42,44). It has also been shown the consumption of diets rich in saturated fat reduced the expression of the orexigenic peptides neuropeptide Y (45) and agouti-related protein (46) in the arcuate nucleus of hypothalamus, and increased the secretion of the anorexigenic cholecystokinin (47).…”

Targeting the orexinergic system: Mainly but not only for sleep-wakefulness therapies

“…Regulation of appetite and stress response [24][25][26] Respiratory effects [27][28][29] Addiction 11,25,26,[30][31][32][33][34][35][36][37][38] Behavioral changes associated with cocaine administration 39 Analgesia 11,40 Food intake regulation 23,41 Central regulation of feeding (of blind cavefish) 42 Regulation of glucose metabolism 43,44 Energy balance regulation 45,46 Insulin secretion regulation 44 Variability in diet-induced obesity sensitivity 47 Proliferation and viability of 3T3-L1 preadipocytes 48 Body temperature regulation 46,49 Neuroendocrine function 6,49,50 Pituitary hormone secretion 51 Cardiovascular activities 49,[52][53][54] Post-ischemic attenuation of inflammatory responses (neuroprotection) 55 Prevention of cerebral ischemic neuronal damage (neuroprotection) 43 Reproduction [56][57]…”