Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats

<p>Abstract</p> <p>Background</p> <p>Phytoestrogens derived from soy foods (or isoflavones) have received prevalent usage due to their 'health benefits' of decreasing: a) age-related diseases, b) hormone-dependent cancers and c) postmenopausal symptoms. Howeve...

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Main Authors: Bu Lihong, Lund Trent D, Porter James P, Lephart Edwin D, Setchell Kenneth DR, Ramoz Gina, Crowley William R
Format: Article
Language:English
Published: BMC 2004-12-01
Series:Nutrition & Metabolism
Online Access:http://www.nutritionandmetabolism.com/content/1/1/16
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author Bu Lihong
Lund Trent D
Porter James P
Lephart Edwin D
Setchell Kenneth DR
Ramoz Gina
Crowley William R
author_facet Bu Lihong
Lund Trent D
Porter James P
Lephart Edwin D
Setchell Kenneth DR
Ramoz Gina
Crowley William R
author_sort Bu Lihong
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Phytoestrogens derived from soy foods (or isoflavones) have received prevalent usage due to their 'health benefits' of decreasing: a) age-related diseases, b) hormone-dependent cancers and c) postmenopausal symptoms. However, little is known about the influence of dietary phytoestrogens on regulatory behaviors, such as food and water intake, metabolic hormones and neuroendocrine parameters. This study examined important hormonal and metabolic health issues by testing the hypotheses that dietary soy-derived isoflavones influence: 1) body weight and adipose deposition, 2) food and water intake, 3) metabolic hormones (i.e., leptin, insulin, T3 and glucose levels), 4) brain neuropeptide Y (NPY) levels, 5) heat production [in brown adipose tissue (BAT) quantifying uncoupling protein (UCP-1) mRNA levels] and 6) core body temperature.</p> <p>Methods</p> <p>This was accomplished by conducting longitudinal studies where male Long-Evans rats were exposed (from conception to time of testing or tissue collection) to a diet rich in isoflavones (at 600 micrograms/gram of diet or 600 ppm) vs. a diet low in isoflavones (at approximately 10–15 micrograms/gram of diet or 10–15 ppm). Body, white adipose tissue and food intake were measured in grams and water intake in milliliters. The hormones (leptin, insulin, T3, glucose and NPY) were quantified by radioimmunoassays (RIA). BAT UCP-1 mRNA levels were quantified by PCR and polyacrylamide gel electrophoresis while core body temperatures were recorded by radio telemetry. The data were tested by analysis of variance (ANOVA) (or where appropriate by repeated measures).</p> <p>Results</p> <p>Body and adipose tissue weights were decreased in Phyto-600 vs. Phyto-free fed rats. Food and water intake was greater in Phyto-600 animals, that displayed higher hypothalamic (NPY) concentrations, but lower plasma leptin and insulin levels, vs. Phyto-free fed males. Higher thyroid levels (and a tendency for higher glucose levels) and increased uncoupling protein (UCP-1) mRNA levels in brown adipose tissue (BAT) were seen in Phyto-600 fed males. However, decreased core body temperature was recorded in these same animals compared to Phyto-free fed animals.</p> <p>Conclusions</p> <p>This study demonstrates that consumption of a soy-based (isoflavone-rich) diet, significantly alters several parameters involved in maintaining body homeostatic balance, energy expenditure, feeding behavior, hormonal, metabolic and neuroendocrine function in male rats.</p>
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spelling doaj.art-048d0d8fa1344df89f822808652ffc5d2022-12-22T02:14:28ZengBMCNutrition & Metabolism1743-70752004-12-01111610.1186/1743-7075-1-16Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male ratsBu LihongLund Trent DPorter James PLephart Edwin DSetchell Kenneth DRRamoz GinaCrowley William R<p>Abstract</p> <p>Background</p> <p>Phytoestrogens derived from soy foods (or isoflavones) have received prevalent usage due to their 'health benefits' of decreasing: a) age-related diseases, b) hormone-dependent cancers and c) postmenopausal symptoms. However, little is known about the influence of dietary phytoestrogens on regulatory behaviors, such as food and water intake, metabolic hormones and neuroendocrine parameters. This study examined important hormonal and metabolic health issues by testing the hypotheses that dietary soy-derived isoflavones influence: 1) body weight and adipose deposition, 2) food and water intake, 3) metabolic hormones (i.e., leptin, insulin, T3 and glucose levels), 4) brain neuropeptide Y (NPY) levels, 5) heat production [in brown adipose tissue (BAT) quantifying uncoupling protein (UCP-1) mRNA levels] and 6) core body temperature.</p> <p>Methods</p> <p>This was accomplished by conducting longitudinal studies where male Long-Evans rats were exposed (from conception to time of testing or tissue collection) to a diet rich in isoflavones (at 600 micrograms/gram of diet or 600 ppm) vs. a diet low in isoflavones (at approximately 10–15 micrograms/gram of diet or 10–15 ppm). Body, white adipose tissue and food intake were measured in grams and water intake in milliliters. The hormones (leptin, insulin, T3, glucose and NPY) were quantified by radioimmunoassays (RIA). BAT UCP-1 mRNA levels were quantified by PCR and polyacrylamide gel electrophoresis while core body temperatures were recorded by radio telemetry. The data were tested by analysis of variance (ANOVA) (or where appropriate by repeated measures).</p> <p>Results</p> <p>Body and adipose tissue weights were decreased in Phyto-600 vs. Phyto-free fed rats. Food and water intake was greater in Phyto-600 animals, that displayed higher hypothalamic (NPY) concentrations, but lower plasma leptin and insulin levels, vs. Phyto-free fed males. Higher thyroid levels (and a tendency for higher glucose levels) and increased uncoupling protein (UCP-1) mRNA levels in brown adipose tissue (BAT) were seen in Phyto-600 fed males. However, decreased core body temperature was recorded in these same animals compared to Phyto-free fed animals.</p> <p>Conclusions</p> <p>This study demonstrates that consumption of a soy-based (isoflavone-rich) diet, significantly alters several parameters involved in maintaining body homeostatic balance, energy expenditure, feeding behavior, hormonal, metabolic and neuroendocrine function in male rats.</p>http://www.nutritionandmetabolism.com/content/1/1/16
spellingShingle Bu Lihong
Lund Trent D
Porter James P
Lephart Edwin D
Setchell Kenneth DR
Ramoz Gina
Crowley William R
Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
Nutrition & Metabolism
title Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
title_full Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
title_fullStr Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
title_full_unstemmed Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
title_short Dietary isoflavones alter regulatory behaviors, metabolic hormones and neuroendocrine function in Long-Evans male rats
title_sort dietary isoflavones alter regulatory behaviors metabolic hormones and neuroendocrine function in long evans male rats
url http://www.nutritionandmetabolism.com/content/1/1/16
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