The effect of high-fat diet on plasma ghrelin and leptin levels in rats

Abstract

Ghrelin and leptin regulate appetite and energy homeostasis in humans and rodents. The effects of different nutritional factors on ghrelin and leptin secretion are not well documented in rats. Therefore, the aim of our study was to investigate the effect of a high-fat diet on plasma ghrelin and leptin levels and on adiposity. Twenty male Wistar rats, body weight 220-260 g, were used in the study. Rats were randomized either on a standard chow diet (n=10) or on a high-fat diet (a mixture of nuts) for ad libitum 11-week period. Body weight was measured once per week. At the end of the nutritional period, rats were sacrificed. Blood was collected for determination of lipids and glucose, as well as plasma ghrelin and leptin levels by ELISA method. The weight of different organs was determined. Rats fed on a high-fat diet showed significant increase in total body weight compared to control group. The long-term intake of high-fat diet caused hyperleptinemia and hypoghrelinemia. There was a significant positive correlation between plasma leptin levels and epididymal fat mass, liver and heart. In contrast, ghrelin levels showed inverse correlation with epididymal fat mass and liver weight. In conclusion, long-term intake of high-fat diet induced changes in plasma ghrelin and leptin in male rats, as well as in epididymal fat mass, liver and heart weights.

Voluntary exercise contributed to an amelioration of abnormal feeding behavior, locomotor activity and ghrelin production concomitantly with a weight reduction in high fat diet-induced obese rats

“…In the HFD-induced obesity state, the ghrelin production was markedly suppressed, which was in agreement with previous reports in human subjects [12,13] and animal models of obesity [33]. The induction of periodic voluntary exercise ameliorated the disrupted ghrelin production to nearly the control levels, with a concomitant decrease in body weight and fat, in line with the results of a human study [15], but conflicting with the results in other reports [16,17].…”

Effect of hyperlipidemia on 11β-hydroxysteroid-dehydrogenase, glucocorticoid receptor, and leptin expression in insulin-sensitive tissues of cats

“…This is in accordance with results from rats, in which high-fat diets led to significantly elevated serum leptin concentrations and significant changes in body mass [38,45]. Feeding a high-fat diet to cats induced a moderate but not significant elevation in leptin levels [26].…”

The modulatory role of high fat feeding on gastrointestinal signals in obesity

“…Centrally, GHSR levels are decreased in the hypothalamus, and NPY/AgRP neuronal signaling is diminished [134]. This compensation is also seen peripherally, as most studies demonstrate a decrease in circulating ghrelin levels of HF fed obese animals [135][136][137][138][139]202], although this is not always the case [221]. For example, in Long-Evans rats fed a HF diet, plasma ghrelin was decreased almost 25% compared to rats fed a control diet with a strong negative correlation between fat intake and ghrelin levels, although there was a similar correlation between fat pad weight and ghrelin levels [135].…”

“…HF feeding reduces levels of active circulating GLP-1 in rodents [121,122]. For example, after 4 weeks of HF feeding, Wistar rats had lower fasting active plasma GLP-1 [121], while 8 weeks of HF feeding in mice led to a 50% reduction in baseline plasma GLP-1(7-36), and a 28.5% reduction in GLP-1 levels 10 min after a glucose [134][135][136][137][138][139][140][141][142] Due to limited data in humans consuming a HF diet, studies with obese humans have also been included. Symbols represent an increase (↑), decrease (↓) or no change (↔) to specified parameter during HF feeding.…”