Neural Mechanisms Responsible for the Regulation of Caloric Intake Following Acute High Fat Diet are Developmentally Regulated

Abstract ATP6AP2 expression is increased in the nephron during high fat diet (HFD) and its knockout (ATP6AP2 KO) reduces body weight (WT) in mice. We evaluated the contribution of ATP6AP2 to urinary glucose (UG) and albumin (Ualb) handling during HFD. We hypothesized that nephron ATP6AP2 KO increases UG and Ualb and minimizes HFD-induced obesity. Eight-week old male C57BL/6J mice with inducible nephron specific ATP6AP2 KO and non-induced controls (C) were fed either normal diet (ND, 12% kcal fat) or HFD (45% kcal fat) for 6 months. ATP6AP2 KO mice on ND had 20% (p<0.01) lower WT compared to C. HFD fed mice had 41% (p<0.05) greater WT than ND fed C. In contrast, ATP6AP2 KO abrogated the increase in WT induced by HFD by 40% (p<0.05). Mice on HFD had less caloric intake compared to ND controls (p<0.01). There were no significant differences in metabolic rate between all groups. UG and Ualb was significantly increased in ATP6AP2 KO mice on both ND and HFD. ATP6AP2 KO showed greater levels of proximal tubule apoptosis and histologic evidence of proximal tubule injury. In conclusion, our results demonstrate that nephron specific ATP6AP2 KO is associated with glucosuria and albuminuria, most likely secondary to renal proximal tubule injury and/or dysfunction. Urinary loss of nutrients may have contributed to the reduced WT of knockout mice on ND and lack of WT gain in response to HFD. Future investigation should elucidate the mechanisms by which loss of renal ATP6AP2 causes proximal tubule injury and dysfunction.

Download Full-text

Fish Oil Enriched in EPA, but Not in DHA, Reverses the Metabolic Syndrome and Adipocyte Dysfunction Induced by a High-Fat Diet

Nutrients ◽

10.3390/nu13030754 ◽

2021 ◽

Vol 13 (3) ◽

pp. 754

Author(s):

Roberta Dourado Cavalcante da Cunha de Sá ◽

Jussara de Jesus Simão ◽

Viviane Simões da Silva ◽

Talita Mendes de Farias ◽

Maysa Mariana Cruz ◽

...

Keyword(s):

Adipose Tissue ◽

Glucose Intolerance ◽

High Fat Diet ◽

Caloric Intake ◽

Omega 3 ◽

High Fat ◽

The Metabolic Syndrome ◽

Tnf Α ◽

Adipocyte Hypertrophy ◽

Partial Reversion

This study aimed to investigate the effects of two commercially available fish oils (FOs) containing different proportions of two omega-3 fatty acids (FA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the metabolic and endocrine dysfunctions of white adipose tissue resulting from obesity. Male C57BL/6J mice, 8 weeks old, received a control or high-fat diet (CO and HF groups, with 9% and 59% energy from fat, respectively) for 8 weeks. The next 8 weeks, the HF group was subdivided into HF, HF+FO/E (HF+5:1 EPA:DHA), and HF+FO/D (HF+5:1 DHA:EPA). Supplementation was performed by gavage, three times a week. All groups that received the HF diet had lower food and caloric intake, but a higher fat intake, body weight (BW) gain, glucose intolerance, and a significant increase in inguinal (ING), retroperitoneal (RP), and epididymal (EPI) adipose tissues when compared to the CO group. Additionally, HF and HF+FO/D groups showed insulin resistance, adipocyte hypertrophy, increased lipolysis and secretion of TNF-α, resistin and IL-10 adipokines by ING and RP adipocytes, and adiponectin only by the HF+FO/D group in ING adipocytes. All of these effects were completely reversed in the HF+FO/E group, which also showed partial reversion in BW gain and glucose intolerance. Both the HF+FO/E and HF+FO/D groups showed a reduction in ING and RP adipose depots when compared to the HF group, but only HF+FO/E in the EPI depot. HF+FO/E, but not HF+FO/D, was able to prevent the changes triggered by obesity in TNF-α, Il-10, and resistin secretion in ING and RP depots. These results strongly suggest that different EPA:DHA ratios have different impacts on the adipose tissue metabolism, FO being rich in EPA, but not in DHA, and effective in reversing the changes induced by obesity.

Download Full-text

Dietary fat stimulates endogenous enkephalin and dynorphin in the paraventricular nucleus: role of circulating triglycerides

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00087.2006 ◽

2007 ◽

Vol 292 (2) ◽

pp. E561-E570 ◽

Cited By ~ 49

Author(s):

G.-Q. Chang ◽

O. Karatayev ◽

R. Ahsan ◽

V. Gaysinskaya ◽

Z. Marwil ◽

...

Keyword(s):

Paraventricular Nucleus ◽

Dietary Fat ◽

Opioid Peptides ◽

High Fat Diet ◽

Caloric Intake ◽

High Fat ◽

Caloric Density ◽

Low Fat Diet ◽

Diet Intake

The opioid peptides enkephalin (ENK) and dynorphin (DYN), when injected into the hypothalamus, are known to stimulate feeding behavior and preferentially increase the ingestion of a high-fat diet. Studies of another peptide, galanin (GAL), with similar effects on feeding demonstrate that a high-fat diet, in turn, can stimulate the expression of this peptide in the hypothalamus. The present study tested different diets and variable periods of high- vs. low-fat diet consumption to determine whether the opioid peptides respond in a similar manner as GAL. In six experiments, the effects of dietary fat on ENK and DYN were examined in three hypothalamic areas: the paraventricular nucleus (PVN), perifornical hypothalamus (PFH), and arcuate nucleus (ARC). The results demonstrated that the ingestion of a high-fat diet increases gene expression and peptide levels of both ENK and DYN in the hypothalamus. The strongest and most consistent effect is seen in the PVN. In this nucleus, ENK and DYN are increased by 50–100% after 1 wk, 1 day, 60 min, and even 15 min of high-fat diet consumption. While showing some effect in the PFH, these peptides in the ARC are considerably less responsive, exhibiting no change in response to the briefer periods of diet intake. This effect of dietary fat on PVN opioids can be observed with diets equal in caloric density and palatability and without a change in caloric intake, body weight, fat pad weight, or levels of insulin or leptin. The data reveal a strong and consistent association between these peptides and a rise in circulating levels of triglycerides, supporting a role for these lipids in the fat-induced stimulation of opioid peptides in the PVN, similar to GAL.

Download Full-text