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Testosterone and Growth Hormone: Age Differences
IronMan November 2002, page 101
"Testosterone injections are known to increase growth hormone levels in young boys and older men, but the effects in younger men, over age 20, aren’t clear. A new study compares two doses of testosterone and its effects on growth hormone response in older (60-82) and younger (20-40) men. For three weeks the men were injected with either saline solution or doses (100 milligrams or 200 milligrams) of testosterone enanthate, a long acting testosterone preparation.
The study found that giving the older men testosterone led to increases in all measures of growth hormone release, along with an elevation in insulinlike growth factor 1 (IGF-1) levels. The testosterone, however, had no effect on GH in the younger men. IGF-1 did rise by 20 percent in the younger men and 40 percent in the older, but that was related to an increase in estrogen levels produced by aromatization, or enzymatic conversion, of the testosterone into estrogen.
The suggested mechanism for how testosterone increases GH levels in older men involves a blunting of somatostatin a substance known to block growth hormone release. Why that didn’t occur in the younger men remains a mystery. That’s good news for older men, since they’re often relatively deficient in both growth hormone and testosterone, leading to detrimental changes in body composition and brain function."
IronMan November 2002, page 101
"Testosterone injections are known to increase growth hormone levels in young boys and older men, but the effects in younger men, over age 20, aren’t clear. A new study compares two doses of testosterone and its effects on growth hormone response in older (60-82) and younger (20-40) men. For three weeks the men were injected with either saline solution or doses (100 milligrams or 200 milligrams) of testosterone enanthate, a long acting testosterone preparation.
The study found that giving the older men testosterone led to increases in all measures of growth hormone release, along with an elevation in insulinlike growth factor 1 (IGF-1) levels. The testosterone, however, had no effect on GH in the younger men. IGF-1 did rise by 20 percent in the younger men and 40 percent in the older, but that was related to an increase in estrogen levels produced by aromatization, or enzymatic conversion, of the testosterone into estrogen.
The suggested mechanism for how testosterone increases GH levels in older men involves a blunting of somatostatin a substance known to block growth hormone release. Why that didn’t occur in the younger men remains a mystery. That’s good news for older men, since they’re often relatively deficient in both growth hormone and testosterone, leading to detrimental changes in body composition and brain function."
