I came across this interesting article ....
One of the most exciting results of 1990's DHEA research has been the discovery that it may enhance insulin-like growth factor -1 (IGF-1) release. IGF-1 (formerly called "Somatomedin C") is the "hidden anabolic power behind the throne" of growth hormone. Growth hormone stimulates the liver to produce and release IGF-1. It is the IGF-1 that then circulates through the bloodstream and leads to the anabolic (tissue-building) actions growth hormone gets credit for. (19)
The Morales/Yen study previously referred to under ENERGY & WELL-BEING above, also found significant increases in both men and women in IGF-1 status. "DHEA replacement induced an approximately 10% rise in serum IGF-1 levels and an approximately 19% decline in IGFBP-1 [IGF-1 binding protein] levels, resulting in an IGF-1/IGFBP-1 ratio by 50% in both men and women." (19) The authors also remark that the increased IGF-1/IGFBP-1 ratios suggest "an increased bioavailability of IGF-1 to target tissues." (19)
Yen, Morales and Khorram conducted a one year double-blind placebo-controlled crossover experiment with 100 mg DHEA with 16 men and women, age 50-65 years. A significant increase in IGF-1 levels occurred in both men and women after 6 months' DHEA treatment, while IGF-1 levels dropped below baseline levels during placebo. Men gained approximately 20% in IGF-1, while women gained about 30% in serum IGF-1. The relative increase in IGF-1 was greater in those with low DHEA-S levels at baseline. (31)
The Jakubowicz study previously mentioned under INSULIN also found a significant increase in IGF-1 from 100 mg DHEA nightly for 30 days. "Serum IGF-1 increased from 96.7 to 183ng/ml (p<0.001). Serum concentration of IGF-1 did not change in the placebo group." (14)
In the Khorram study previously mentioned under IMMUNE ASPECTS, 50 mg DHEA daily for 20 weeks also led to increased IGF-1. Khorram et al note that "DHEA administration resulted in a 20% increase (p < 0.01) in serum IGF-1m a decreasing trend in IGFBP-1, and a 32% increase in the ratio of IGF-1 /IGFBP-1 (p< 0.01)." (10) The authors also report a 4-fold increase in the DHEA-S/cortisol ratio. (10) As will become evident shortly, this major increase in DHEA-S/cortisol ratio may hold the key to many of DHEA's diverse benefits.
In 1995 E. Bernton and colleagues reported their results from testing U.S. Army Ranger School trainees during their gruelling training, which included a loss of 8-15% of bodyweight over 8 weeks from intentional caloric deprivation and continuous physical work, limitation of sleep to 4 hours per night, and long exposures to extreme environments.
They reported a decrease in mean salivary DHEA/cortisol ratio from 0.076 to 0.041 (p< 0.001), and a mean decrease of serum IGF-1 of 60% during Ranger training, while growth hormone increased 4-fold, "reflecting a dissociation of growth hormone from IGF-1 secretion, attributable in part to negative [food] energy balance and high cortisol levels. In vivo, IGF-1 levels are therefore increased by glucocorticoids [i.e. cortisol] and increased by DHEA. We hypothesize that tissue ratios of DHEA to cortisol may regulate IGF-1 secretion in stressed individuals such as ranger trainees." (25)
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19) Morales, A. et al (1994) "Effects of replacement dose of dehydroepiandrosterone in men and women of advancing age" J Clin Endocrinol Metab 78: 1360-67.
31) Yen, S.S.C. et al (1995) "Replacement of DHEA in aging men and women" Ann NY Acad Sci 774: 128-42.
25) Bernton, E. et al (1995) "Adaptation to chronic stress in military trainees" Ann NY Acad Sci 774: 217-31.
14) Jakubowicz, D. et al (1995) "Effect of dehydroepiandrosterone on cyclic-guanosine monophosphate in age-advanced men" Ann NY Acad Sci 774: 312-15.
One of the most exciting results of 1990's DHEA research has been the discovery that it may enhance insulin-like growth factor -1 (IGF-1) release. IGF-1 (formerly called "Somatomedin C") is the "hidden anabolic power behind the throne" of growth hormone. Growth hormone stimulates the liver to produce and release IGF-1. It is the IGF-1 that then circulates through the bloodstream and leads to the anabolic (tissue-building) actions growth hormone gets credit for. (19)
The Morales/Yen study previously referred to under ENERGY & WELL-BEING above, also found significant increases in both men and women in IGF-1 status. "DHEA replacement induced an approximately 10% rise in serum IGF-1 levels and an approximately 19% decline in IGFBP-1 [IGF-1 binding protein] levels, resulting in an IGF-1/IGFBP-1 ratio by 50% in both men and women." (19) The authors also remark that the increased IGF-1/IGFBP-1 ratios suggest "an increased bioavailability of IGF-1 to target tissues." (19)
Yen, Morales and Khorram conducted a one year double-blind placebo-controlled crossover experiment with 100 mg DHEA with 16 men and women, age 50-65 years. A significant increase in IGF-1 levels occurred in both men and women after 6 months' DHEA treatment, while IGF-1 levels dropped below baseline levels during placebo. Men gained approximately 20% in IGF-1, while women gained about 30% in serum IGF-1. The relative increase in IGF-1 was greater in those with low DHEA-S levels at baseline. (31)
The Jakubowicz study previously mentioned under INSULIN also found a significant increase in IGF-1 from 100 mg DHEA nightly for 30 days. "Serum IGF-1 increased from 96.7 to 183ng/ml (p<0.001). Serum concentration of IGF-1 did not change in the placebo group." (14)
In the Khorram study previously mentioned under IMMUNE ASPECTS, 50 mg DHEA daily for 20 weeks also led to increased IGF-1. Khorram et al note that "DHEA administration resulted in a 20% increase (p < 0.01) in serum IGF-1m a decreasing trend in IGFBP-1, and a 32% increase in the ratio of IGF-1 /IGFBP-1 (p< 0.01)." (10) The authors also report a 4-fold increase in the DHEA-S/cortisol ratio. (10) As will become evident shortly, this major increase in DHEA-S/cortisol ratio may hold the key to many of DHEA's diverse benefits.
In 1995 E. Bernton and colleagues reported their results from testing U.S. Army Ranger School trainees during their gruelling training, which included a loss of 8-15% of bodyweight over 8 weeks from intentional caloric deprivation and continuous physical work, limitation of sleep to 4 hours per night, and long exposures to extreme environments.
They reported a decrease in mean salivary DHEA/cortisol ratio from 0.076 to 0.041 (p< 0.001), and a mean decrease of serum IGF-1 of 60% during Ranger training, while growth hormone increased 4-fold, "reflecting a dissociation of growth hormone from IGF-1 secretion, attributable in part to negative [food] energy balance and high cortisol levels. In vivo, IGF-1 levels are therefore increased by glucocorticoids [i.e. cortisol] and increased by DHEA. We hypothesize that tissue ratios of DHEA to cortisol may regulate IGF-1 secretion in stressed individuals such as ranger trainees." (25)
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19) Morales, A. et al (1994) "Effects of replacement dose of dehydroepiandrosterone in men and women of advancing age" J Clin Endocrinol Metab 78: 1360-67.
31) Yen, S.S.C. et al (1995) "Replacement of DHEA in aging men and women" Ann NY Acad Sci 774: 128-42.
25) Bernton, E. et al (1995) "Adaptation to chronic stress in military trainees" Ann NY Acad Sci 774: 217-31.
14) Jakubowicz, D. et al (1995) "Effect of dehydroepiandrosterone on cyclic-guanosine monophosphate in age-advanced men" Ann NY Acad Sci 774: 312-15.