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The impact of high fat diets on physiological changes in euthyroid and thyroid altered rats.

Welch-White V, Dawkins N, Graham T, Pace R - Lipids Health Dis (2013)

Bottom Line: HbA1C values and urinary glucose values were within normal range for all animals.Liver morphology showed increased hepatic stellate (ito) and vacuole cells in thyroid altered animals.These findings suggest that altered thyroid status negatively impacts growth and weight gain, and simultaneously affected lipid metabolism, resulting in abnormal liver morphology.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Food and Nutritional Sciences, Tuskegee University, 204 Campbell Hall, Tuskegee, AL 36088, USA.

ABSTRACT
The association of adverse health with high fat intake has long been recognized. However, the lack of research focusing on the interrelationship of thyroid and liver function, and the pathogenesis of a high fat diet leaves these topics poorly understood. The objective of this study was to evaluate and compare the physiological changes in euthyroid and thyroid altered animal model fed saturated and unsaturated high fat diets. To achieve this objective adult male Sprague Dawley rats (n = 100) were fed one of five diets; a control or one of four test diets containing 25% saturated or unsaturated, and 37% saturated or unsaturated fats for a period of eight weeks. Each experimental group consisted of ten euthyroid and ten thyroid altered animals. An altered thyroid state was chemically induced with the addition of 0.05% propylthiouracil (PTU) in the drinking water. Euthyroid animals fed high fat diets increased in body weights and body lengths, compared to thyroid altered animals (P < 0.05). Alanine aminotransferase (ALT) and asparte aminotransferase (AST) levels increased across all experimental groups. HbA1C values and urinary glucose values were within normal range for all animals. Liver morphology showed increased hepatic stellate (ito) and vacuole cells in thyroid altered animals. These findings suggest that altered thyroid status negatively impacts growth and weight gain, and simultaneously affected lipid metabolism, resulting in abnormal liver morphology.

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Experimental groups and test diets. Five of the experimental groups were comprised of normal or euthyroid rats, and the remaining five experimental groups contained thyroid altered animals. Each diet of the five diets were fed to a normal (euthyroid) group as well as a thyroid altered group. Saturated fat diets contain lard as the fat source, while unsaturated diets contain soy oil.
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Figure 3: Experimental groups and test diets. Five of the experimental groups were comprised of normal or euthyroid rats, and the remaining five experimental groups contained thyroid altered animals. Each diet of the five diets were fed to a normal (euthyroid) group as well as a thyroid altered group. Saturated fat diets contain lard as the fat source, while unsaturated diets contain soy oil.

Mentions: One hundred, 30 – 35 day old male Sprague Dawley rats, with a mean weight of 100 g were obtained from Harlan Sprague Dawley Laboratories, Inc. (Indianapolis, IN). The animals were housed two per stainless steel cage (60 cm × 60 cm × 15 cm), quarantined for 7 -d (fed rodent lab chow) and acclimatized to the respective diets for 7-d, after arrival at the university’s, College of Veterinary Medicine Comparative Medicine Resource Center. The room temperature was 21 ± 1 C with relative humidity of 50 ± 5% and a light/dark cycle of 12 hours (light 8:00 – 20:00). Ten animals were weighed and randomly assigned to one of ten experimental groups (n = 100); (Figure 3). Euthyroid and thyroid altered animals were pair fed one of the five diets (control , 25% lard, 25% soy, 37% lard and 37% soy) for 8-weeks and had access to water ad libitum throughout the duration of the study. PTU was administered orally and continuously to five experimental groups (n = 50) in the drinking water at 0.05% (w/v) for 6 weeks. Corn syrup was added to the drinking water to increase palatability in the PTU- treated groups, and as a control in the non-treated groups. PTU inhibits the mechanism of thyroid iodide peroxidase (TPO) resulting in a chemically-altered thyroid state the models [40]. Feed consumption was measured daily and the animals were weighed weekly. Body lengths were measure at the conclusion of the study. The rats were fasted overnight on the final day of the study, prior to euthanasia from overexposure to CO2. All experimental procedures were conducted according to the approved protocols and guidelines of the university’s Animal Care and Use Committee.


The impact of high fat diets on physiological changes in euthyroid and thyroid altered rats.

Welch-White V, Dawkins N, Graham T, Pace R - Lipids Health Dis (2013)

Experimental groups and test diets. Five of the experimental groups were comprised of normal or euthyroid rats, and the remaining five experimental groups contained thyroid altered animals. Each diet of the five diets were fed to a normal (euthyroid) group as well as a thyroid altered group. Saturated fat diets contain lard as the fat source, while unsaturated diets contain soy oil.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733864&req=5

Figure 3: Experimental groups and test diets. Five of the experimental groups were comprised of normal or euthyroid rats, and the remaining five experimental groups contained thyroid altered animals. Each diet of the five diets were fed to a normal (euthyroid) group as well as a thyroid altered group. Saturated fat diets contain lard as the fat source, while unsaturated diets contain soy oil.
Mentions: One hundred, 30 – 35 day old male Sprague Dawley rats, with a mean weight of 100 g were obtained from Harlan Sprague Dawley Laboratories, Inc. (Indianapolis, IN). The animals were housed two per stainless steel cage (60 cm × 60 cm × 15 cm), quarantined for 7 -d (fed rodent lab chow) and acclimatized to the respective diets for 7-d, after arrival at the university’s, College of Veterinary Medicine Comparative Medicine Resource Center. The room temperature was 21 ± 1 C with relative humidity of 50 ± 5% and a light/dark cycle of 12 hours (light 8:00 – 20:00). Ten animals were weighed and randomly assigned to one of ten experimental groups (n = 100); (Figure 3). Euthyroid and thyroid altered animals were pair fed one of the five diets (control , 25% lard, 25% soy, 37% lard and 37% soy) for 8-weeks and had access to water ad libitum throughout the duration of the study. PTU was administered orally and continuously to five experimental groups (n = 50) in the drinking water at 0.05% (w/v) for 6 weeks. Corn syrup was added to the drinking water to increase palatability in the PTU- treated groups, and as a control in the non-treated groups. PTU inhibits the mechanism of thyroid iodide peroxidase (TPO) resulting in a chemically-altered thyroid state the models [40]. Feed consumption was measured daily and the animals were weighed weekly. Body lengths were measure at the conclusion of the study. The rats were fasted overnight on the final day of the study, prior to euthanasia from overexposure to CO2. All experimental procedures were conducted according to the approved protocols and guidelines of the university’s Animal Care and Use Committee.

Bottom Line: HbA1C values and urinary glucose values were within normal range for all animals.Liver morphology showed increased hepatic stellate (ito) and vacuole cells in thyroid altered animals.These findings suggest that altered thyroid status negatively impacts growth and weight gain, and simultaneously affected lipid metabolism, resulting in abnormal liver morphology.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Food and Nutritional Sciences, Tuskegee University, 204 Campbell Hall, Tuskegee, AL 36088, USA.

ABSTRACT
The association of adverse health with high fat intake has long been recognized. However, the lack of research focusing on the interrelationship of thyroid and liver function, and the pathogenesis of a high fat diet leaves these topics poorly understood. The objective of this study was to evaluate and compare the physiological changes in euthyroid and thyroid altered animal model fed saturated and unsaturated high fat diets. To achieve this objective adult male Sprague Dawley rats (n = 100) were fed one of five diets; a control or one of four test diets containing 25% saturated or unsaturated, and 37% saturated or unsaturated fats for a period of eight weeks. Each experimental group consisted of ten euthyroid and ten thyroid altered animals. An altered thyroid state was chemically induced with the addition of 0.05% propylthiouracil (PTU) in the drinking water. Euthyroid animals fed high fat diets increased in body weights and body lengths, compared to thyroid altered animals (P < 0.05). Alanine aminotransferase (ALT) and asparte aminotransferase (AST) levels increased across all experimental groups. HbA1C values and urinary glucose values were within normal range for all animals. Liver morphology showed increased hepatic stellate (ito) and vacuole cells in thyroid altered animals. These findings suggest that altered thyroid status negatively impacts growth and weight gain, and simultaneously affected lipid metabolism, resulting in abnormal liver morphology.

Show MeSH
Related in: MedlinePlus