Journal of Nutrition. 2001;131:2150-2156.)
© 2001 The American Society for Nutritional Sciences
Articles
Garlic Supplementation Increases Testicular Testosterone and Decreases Plasma Corticosterone in Rats Fed a High Protein Diet
Yuriko Oi1, Mika Imafuku, Chiaki Shishido, Yutaka Kominato*, Syoji Nishimura* and Kazuo Iwai
Laboratory of Nutrition Chemistry, Faculty of Home Economics, Kobe Women’s University, Suma-ku, Kobe 654-8585, Japan and * Riken Chemical Industry Limited Company, Fushimi-ku, Kyoto 612-8404, Japan
1To whom correspondence should be addressed. E-mail: oi@suma.kobe-wu.ac.jp .
The effects of garlic supplementation on protein metabolism were investigated by measuring testis testosterone and plasma corticosterone in rats fed diets with different protein levels. In Experiment 1, rats were fed experimental diets with different protein levels (40, 25 or 10 g/100 g casein) with or without 0.8 g/100 g garlic powder. After 28 d of feeding, testosterone contents in the testis were significantly higher and plasma corticosterone concentrations were significantly lower in rats fed 40 and 25% casein diets with garlic powder than in those fed the same diets without garlic powder. Urinary excretion of 17-ketosteroid (an index of testosterone), nitrogen balance and hepatic arginase activity were significantly higher in rats fed the 40% casein diet with garlic powder than in the 40% casein controls. In Experiment 2, the effect of diallyldisulfide (a major volatile sulfur-containing compound in garlic) on the secretion of luteinizing hormone (LH) from the pituitary gland, which regulates testosterone production in the testis, was investigated in anesthetized rats. Plasma LH concentration increased dose dependently after administration of diallyldisulfide (P < 0.01, r = 0.558). These results suggest that dietary supplementation with 0.8 g/100 g garlic alters hormones associated with protein anabolism by increasing testicular testosterone and decreasing plasma corticosterone in rats fed a high protein diet.
e ancora:
Garlic and its oils have also been the focus of considerable research, too. Effects that would interest athletes include increasedTestosterone , decreased cortisol, and improved nitrogen balance in rats, (43) reduced blood glucose in men, (59) improved feed efficiency and weight gain in hamsters (32) and enhanced total antioxidant activity in humans and animals (32, 59). Again we the see the (dietary oil-associated) improved endocrine response. And although it depends on one's initial levels, blood lipid improvements may also occur (60), along with purported pro-circulatory effects and reduced blood clotting (14), all of which have led to worldwide use ofgarlic to combat heart disease.(1) These latter effects should be of interest to any health conscious person
© 2001 The American Society for Nutritional Sciences
Articles
Garlic Supplementation Increases Testicular Testosterone and Decreases Plasma Corticosterone in Rats Fed a High Protein Diet
Yuriko Oi1, Mika Imafuku, Chiaki Shishido, Yutaka Kominato*, Syoji Nishimura* and Kazuo Iwai
Laboratory of Nutrition Chemistry, Faculty of Home Economics, Kobe Women’s University, Suma-ku, Kobe 654-8585, Japan and * Riken Chemical Industry Limited Company, Fushimi-ku, Kyoto 612-8404, Japan
1To whom correspondence should be addressed. E-mail: oi@suma.kobe-wu.ac.jp .
The effects of garlic supplementation on protein metabolism were investigated by measuring testis testosterone and plasma corticosterone in rats fed diets with different protein levels. In Experiment 1, rats were fed experimental diets with different protein levels (40, 25 or 10 g/100 g casein) with or without 0.8 g/100 g garlic powder. After 28 d of feeding, testosterone contents in the testis were significantly higher and plasma corticosterone concentrations were significantly lower in rats fed 40 and 25% casein diets with garlic powder than in those fed the same diets without garlic powder. Urinary excretion of 17-ketosteroid (an index of testosterone), nitrogen balance and hepatic arginase activity were significantly higher in rats fed the 40% casein diet with garlic powder than in the 40% casein controls. In Experiment 2, the effect of diallyldisulfide (a major volatile sulfur-containing compound in garlic) on the secretion of luteinizing hormone (LH) from the pituitary gland, which regulates testosterone production in the testis, was investigated in anesthetized rats. Plasma LH concentration increased dose dependently after administration of diallyldisulfide (P < 0.01, r = 0.558). These results suggest that dietary supplementation with 0.8 g/100 g garlic alters hormones associated with protein anabolism by increasing testicular testosterone and decreasing plasma corticosterone in rats fed a high protein diet.
e ancora:
Garlic and its oils have also been the focus of considerable research, too. Effects that would interest athletes include increasedTestosterone , decreased cortisol, and improved nitrogen balance in rats, (43) reduced blood glucose in men, (59) improved feed efficiency and weight gain in hamsters (32) and enhanced total antioxidant activity in humans and animals (32, 59). Again we the see the (dietary oil-associated) improved endocrine response. And although it depends on one's initial levels, blood lipid improvements may also occur (60), along with purported pro-circulatory effects and reduced blood clotting (14), all of which have led to worldwide use ofgarlic to combat heart disease.(1) These latter effects should be of interest to any health conscious person
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