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5 results on '"Phyllis S. Y. Tam"'

1. Unsaturated Fatty Acids in Fish Oil Play a Role in Adequate Fat Distribution to Plasma, Liver and White Adipose Tissue

Author

Kanako Ito, Masaki Wakutsu, Yoko Fujiwara, Keizo Kasono, Etsuko Muraki, Mariko Sonoda, Shinji Ikemoto, Nobuyo Tsunoda, Sachiko Shiba, and Phyllis S. Y. Tam

Subjects
chemistry.chemical_classification, Triglyceride, unsaturated fatty acid, Health, Toxicology and Mutagenesis, Fatty acid, Lipid metabolism, White adipose tissue, Biology, Toxicology, Fish oil, fish oil, 魚油, chemistry.chemical_compound, Oleic acid, オレイン酸, chemistry, Biochemistry, oleic acid, パルミトオレイン酸, 不飽和脂肪酸, Palmitoleic acid, lipids (amino acids, peptides, and proteins), Food science, Unsaturated fatty acid, palmitoleic acid
Abstract

The components bringing the effects of fish oil on glucose and lipid metabolism are unclear. We used hydrogenated fish oil, which has saturated fatty acids with the same carbon chain lengths as the unsaturated fatty acids in fish oil, to clarify the functions of these unsaturated fatty acids on the improvements in lipid and glucose metabolism in mice. Mice divided into 3 groups were fed different diets: fish oil diet (FO), hydrogenated fish oil diet (HFO), and soybean oil diet (SBO) as a control. Body weight gain and white adipose tissue weight in the HFO and FO groups were significantly decreased compared with those in the SBO group. However, in the HFO group, the triglyceride (TG) levels in plasma were significantly decreased, while the lipids levels in the liver were remarkably increased compared with those in the FO group. Regarding the fatty acid composition in the liver and white adipose tissue in the HFO group, in parallel with the up-regulation of stearoyl-CoA desaturase 1 mRNA, relative amounts of C16 : 1 and C18 : 1 were significantly increased. By contrast, blood glucose levels in the oral glucose tolerance test had not deteriorated in the HFO group. Our results indicate that unsaturated fatty acids in the FO diet decrease lipid levels in the liver and maintain the balance of lipid levels in plasma, liver and white adipose tissue; in addition, in the HFO group, C16 : 1 and C18 : 1 synthesized in the liver and white adipose tissue may improve glucose tolerance and lipid metabolism.

Published
2011

2. The Metabolism and Distribution of Docosapentaenoic Acid (n-6) in the Liver and Testis of Growing Rats

Author

Yoko Fujiwara, Phyllis S. Y. Tam, Yan Cui, Akiyo Matsumoto, and Rumi Sawada

Subjects
Male, medicine.medical_specialty, Linoleic acid, delta-6 desaturase, Biology, Applied Microbiology and Biotechnology, Biochemistry, Linoleoyl-CoA Desaturase, Gene Expression Regulation, Enzymologic, Analytical Chemistry, chemistry.chemical_compound, Internal medicine, Testis, medicine, arachidonic acid, Weaning, Animals, retroconversion, RNA, Messenger, docosapentaenoic acid, Molecular Biology, chemistry.chemical_classification, Organic Chemistry, Fatty acid, Docosapentaenoic Acid n-6, General Medicine, Metabolism, Organ Size, docosahexaenoic acid, Animal Feed, Rats, Endocrinology, Milk, chemistry, Liver, Docosahexaenoic acid, Fatty Acids, Unsaturated, Arachidonic acid, Female, Docosapentaenoic acid, Biotechnology
Abstract

To investigate the metabolism and distribution of docosapentaenoic acid (22:5n-6, DPA) in the liver and testis of growing rats, 22:5n-6 was administered to their dams. Newborn rats with a low hepatic arachidonic acid (20:4n-6, AA) level were generated by administrating a diet rich in docosahexaenoic acid (22:6n-3, DHA) but n-6 fatty acid (FA) free to pregnant dams. After parturition, 22:5n-6 or linoleic acid (18:2n-6, LA) was administered with a high level of 22:6n-3 to the dams until weaning. At weaning, the hepatic 20:4n-6 level was significantly highest in the DPA-DHA but not LA-DHA diet-fed animals. The hepatic delta-6 desaturase (D6D) mRNA abundance was significantly lower in both the LA-DHA and DPA-DHA diet-fed animals, connoted with the 20:4n-6 content recovered by 22:5n-6 that did not involve D6D and supporting the occurrence of retroconversion in the liver of the growing rats. The low D6D level in the 3-week-old testis was not in proportion to the elevated 22:5n-6 level, implying that early testicular 22:5n-6 accumulation might require supply from the circulation system.

Published
2008

3. Regulation of Lipid Metabolism by Palmitoleate and Eicosapentaenoic Acid (EPA) in Mice Fed a High-Fat Diet

Author

Phyllis S. Y. Tam, Nobuyo Tsunoda, Shinji Ikemoto, Keizo Kasono, Etsuko Muraki, Yoko Fujiwara, Mariko Sonoda, Sachiko Shiba, and Masaki Wakutsu

Subjects
Male, medicine.medical_specialty, Administration, Oral, Diet, High-Fat, Applied Microbiology and Biotechnology, Biochemistry, fish oil, Analytical Chemistry, Fatty Acids, Monounsaturated, Mice, Oral administration, Internal medicine, lipid metabolism, medicine, Animals, palmitoleate, Molecular Biology, Chemistry, Organic Chemistry, Body Weight, Lipid metabolism, High fat diet, EPA, General Medicine, Fish oil, Eicosapentaenoic acid, Mice, Inbred C57BL, Endocrinology, high-fat diet, Fat diet, Eicosapentaenoic Acid, lipids (amino acids, peptides, and proteins), Energy Intake, Biotechnology
Abstract

We investigated whether oral administration of palmitoleate ameliorates disorders of lipid metabolism to clarify the effects of one of the components of fish oil. Lipid levels in the liver and plasma were significantly decreased by palmitoleate and by EPA administration. These results suggest that palmitoleate, in addition to EPA, plays a role in the regulation of lipid metabolism by fish oil.

Published
2011

4. The metabolism and distribution of docosapentaenoic acid (n−6) in rats and rat hepatocytes

Author

Phyllis S. Y. Tam, Osamu Igarashi, Toshiaki Yaguchi, Kengo Akimoto, Rumi Umeda-Sawada, and Yoshinobu Kiso

Subjects
Male, medicine.medical_specialty, Docosahexaenoic Acids, Clinical chemistry, Linoleic acid, Biochemistry, chemistry.chemical_compound, Dietary Fats, Unsaturated, Internal medicine, Testis, medicine, Animals, Rats, Wistar, Cells, Cultured, Brain Chemistry, Arachidonic Acid, Fatty Acids, fungi, Organic Chemistry, food and beverages, Docosapentaenoic Acid n-6, Cell Biology, Metabolism, Rats, Endocrinology, Liver, chemistry, Organ Specificity, Docosahexaenoic acid, Fatty Acids, Unsaturated, lipids (amino acids, peptides, and proteins), Arachidonic acid, Docosapentaenoic acid, Lipidology
Abstract

In this study, a new marine oil that contains 45% docosahexaenoic acid (DHA, 22:6n-3) and 13% docosapentaenoic acid (DPA, 22:5n-6) was administered to rats. The metabolism and distribution of DPA in rats was investigated. In experiment 1, the effects of DHA and n-6 fatty acids (linoleic acid, LA; arachidonic acid, AA; and DPA) on AA contents were investigated in vivo. LA group: LA 25%, DHA 30%; LA-DPA group: LA 15%, DPA 10%, DHA 35%; LA-AA-DPA group: LA 10%, AA 5%, DPA 10%, DHA 35% were administered to rats for 4 wk. In the liver, the AA content in the LA-DPA and LA-AA-DPA groups was significantly higher than in the LA group. The decreased AA contents in the LA group might be caused by DHA administration. Although DHA also was administered in the LA-DPA and LA-AA-DPA groups, the AA contents in these two groups did not decrease. These results suggested that DPA retroconverted to AA, blunting the decrease in AA content caused by DHA administration. To conduct a detailed investigation on DPA metabolism and its relation with AA and DHA, rat hepatocytes were cultured with purified DPA and DHA for 24 h. We discovered the retroconversion of DPA to AA occurred only when AA content was decreased by a high DHA administration; it did not occur when AA content was maintained at a normal level.

Published
2000

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