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Calorie Restricted High Protein Diets Downregulate Lipogenesis and Lower Intrahepatic Triglyceride Concentrations in Male Rats

View Article: PubMed Central - PubMed

ABSTRACT

The purpose of this investigation was to assess the influence of calorie restriction (CR) alone, higher-protein/lower-carbohydrate intake alone, and combined CR higher-protein/lower-carbohydrate intake on glucose homeostasis, hepatic de novo lipogenesis (DNL), and intrahepatic triglycerides. Twelve-week old male Sprague Dawley rats consumed ad libitum (AL) or CR (40% restriction), adequate (10%), or high (32%) protein (PRO) milk-based diets for 16 weeks. Metabolic profiles were assessed in serum, and intrahepatic triglyceride concentrations and molecular markers of de novo lipogenesis were determined in liver. Independent of calorie intake, 32% PRO tended to result in lower homeostatic model assessment of insulin resistance (HOMA-IR) values compared to 10% PRO, while insulin and homeostatic model assessment of β-cell function (HOMA-β) values were lower in CR than AL, regardless of protein intake. Intrahepatic triglyceride concentrations were 27.4 ± 4.5 and 11.7 ± 4.5 µmol·g−1 lower (p < 0.05) in CR and 32% PRO compared to AL and 10% PRO, respectively. Gene expression of fatty acid synthase (FASN), stearoyl-CoA destaurase-1 (SCD1) and pyruvate dehydrogenase kinase, isozyme 4 (PDK4) were 45% ± 1%, 23% ± 1%, and 57% ± 1% lower (p < 0.05), respectively, in CR than AL, regardless of protein intake. Total protein of FASN and SCD were 50% ± 1% and 26% ± 1% lower (p < 0.05) in 32% PRO compared to 10% PRO, independent of calorie intake. Results from this investigation provide evidence that the metabolic health benefits associated with CR—specifically reduction in intrahepatic triglyceride content—may be enhanced by consuming a higher-protein/lower-carbohydrate diet.

No MeSH data available.


Correlation of intrahepatic triglycerides (IHTG) to whole-body fat (A); IHTG to serum insulin (B); IHTG to FASN gene expression (C); and IHTG to PDK4 gene expression (D). All correlations significant; p < 0.05.
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nutrients-08-00571-f004: Correlation of intrahepatic triglycerides (IHTG) to whole-body fat (A); IHTG to serum insulin (B); IHTG to FASN gene expression (C); and IHTG to PDK4 gene expression (D). All correlations significant; p < 0.05.

Mentions: Whole-body fat mass was positively associated with intrahepatic triglyceride concentrations (r = 0.754, r2 = 0.451; p < 0.01; Figure 4A). Intrahepatic triglycerides were positively associated with circulating insulin concentrations (r = 0.634, r2 = 0.253; p < 0.01; Figure 4B) and FASN gene expression (r = 0.458, r2 = 0.171; p < 0.01; Figure 4C). Additionally, a positive correlation was observed with PDK4 and intrahepatic triglycerides (r = 0.634, r2 = 0.262; p < 0.01; Figure 4D).


Calorie Restricted High Protein Diets Downregulate Lipogenesis and Lower Intrahepatic Triglyceride Concentrations in Male Rats
Correlation of intrahepatic triglycerides (IHTG) to whole-body fat (A); IHTG to serum insulin (B); IHTG to FASN gene expression (C); and IHTG to PDK4 gene expression (D). All correlations significant; p < 0.05.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037556&req=5

nutrients-08-00571-f004: Correlation of intrahepatic triglycerides (IHTG) to whole-body fat (A); IHTG to serum insulin (B); IHTG to FASN gene expression (C); and IHTG to PDK4 gene expression (D). All correlations significant; p < 0.05.
Mentions: Whole-body fat mass was positively associated with intrahepatic triglyceride concentrations (r = 0.754, r2 = 0.451; p < 0.01; Figure 4A). Intrahepatic triglycerides were positively associated with circulating insulin concentrations (r = 0.634, r2 = 0.253; p < 0.01; Figure 4B) and FASN gene expression (r = 0.458, r2 = 0.171; p < 0.01; Figure 4C). Additionally, a positive correlation was observed with PDK4 and intrahepatic triglycerides (r = 0.634, r2 = 0.262; p < 0.01; Figure 4D).

View Article: PubMed Central - PubMed

ABSTRACT

The purpose of this investigation was to assess the influence of calorie restriction (CR) alone, higher-protein/lower-carbohydrate intake alone, and combined CR higher-protein/lower-carbohydrate intake on glucose homeostasis, hepatic de novo lipogenesis (DNL), and intrahepatic triglycerides. Twelve-week old male Sprague Dawley rats consumed ad libitum (AL) or CR (40% restriction), adequate (10%), or high (32%) protein (PRO) milk-based diets for 16 weeks. Metabolic profiles were assessed in serum, and intrahepatic triglyceride concentrations and molecular markers of de novo lipogenesis were determined in liver. Independent of calorie intake, 32% PRO tended to result in lower homeostatic model assessment of insulin resistance (HOMA-IR) values compared to 10% PRO, while insulin and homeostatic model assessment of &beta;-cell function (HOMA-&beta;) values were lower in CR than AL, regardless of protein intake. Intrahepatic triglyceride concentrations were 27.4 &plusmn; 4.5 and 11.7 &plusmn; 4.5 &micro;mol&middot;g&minus;1 lower (p &lt; 0.05) in CR and 32% PRO compared to AL and 10% PRO, respectively. Gene expression of fatty acid synthase (FASN), stearoyl-CoA destaurase-1 (SCD1) and pyruvate dehydrogenase kinase, isozyme 4 (PDK4) were 45% &plusmn; 1%, 23% &plusmn; 1%, and 57% &plusmn; 1% lower (p &lt; 0.05), respectively, in CR than AL, regardless of protein intake. Total protein of FASN and SCD were 50% &plusmn; 1% and 26% &plusmn; 1% lower (p &lt; 0.05) in 32% PRO compared to 10% PRO, independent of calorie intake. Results from this investigation provide evidence that the metabolic health benefits associated with CR&mdash;specifically reduction in intrahepatic triglyceride content&mdash;may be enhanced by consuming a higher-protein/lower-carbohydrate diet.

No MeSH data available.