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The hypothalamus is the primitive site of the brain that sends either stimulating or inhibiting hormones to the pituitary. Growth hormone stimulating hormone (GHRH) tells the pituitary gland to secrete more growth hormone (GH). On the other side, Growth Hormone Inhibiting Hormone (GHIH = Somatostatin) tells the pituitary gland to stop producing more GH. Once the pituitary receives the positive stimulating signal it then secretes GH which in turn stimulates the liver to produce IGF-1 (Insulin-like growth factor 1) . This is the substance that is most commonly measured as a surrogate marker for GH output. Low IGF-1 = low GH. Somatomedin-C is just another name for IGF-1. Depending on the lab, it might be useful to identify both to clear up any confusion. IGF-1 is also a more stable compound unlike true GH which has up to 5 spurts a day - the largest being just before sleep. If we were to measure GH directly it might show as too low or too high just because of the timing. Measuring IGF-1 circumvents this problem because of its more constant blood levels. Interestingly, both have distinct biochemical properties. Once the IGF-1 levels are high enough, a feedback message is sent back to the pituitary and the hypothalamus to modulate further GH secretion. This is accomplished by secreting more Somatostatin which then slows down GH production. You can see the intricate play between GHRH and Somatostatin as a "servo" mechanism in the brain to regulate just the right amount of GH release. This is the model for virtually all brain mediated hormonal control - the thyroid, adrenals, ovaries and testes. Critical concept: As we age, GH output begins to fall off, whether by sluggishness of pituitary secretion or because of true GH decline. The outcome is the same: declining levels of GH which given rise to a plethora of symptoms which we know are the telltale signs of aging: * Loss of elasticity - thinning, sagging and wrinkled skin * Loss of bone strength - osteoporosis * Loss of Muscle strength - frailty and weakness * Increased adipose tissue - accumulation of fat * Loss of heart muscle contractility - heart failure * Less favorable lipid profile - increased cholesterol and decreased HDL * Loss of vigor and stamina * Loss of sexual powers and libido Clinical Studies It all started with the seminal Rudman study published in the New England Journal of Medicine (NEJM; 323:1-6 1990). This pilot study divided 21 men 61-81 years old with plasma IGF-1 levels less than 350 iu per liter into two groups: 12 test subjects and 9 controls subjects. A six month base period of data collection preceded the six month test (GH injection) period. The study showed an increase in lean muscle mass, a decrease in adipose fat tissue, and an increase in vertebral bone height. All test subjects had measurable increases in their IGF-1 blood values. The control group showed none of the above benefits. To quote: "The effects of six months of human growth hormone online body mass and adipose-tissue mass were equivalent in magnitude to the changes incurred during the 10 to 20 years of aging. In other words, regression of aging by 10-20 years. (See also the Danish Jorgenson study) Later Chien and Terry's large group of over 1000 clinically treated individuals showed that lower dose, higher frequency administration (twice daily) is associated with virtually no side effects and substantial benefits: * muscle strength, exercise, and body fat * Increase in skin elasticity, texture and tightness * Increased healing, flexibility and resistance * Increased sexual potency and frequency * Increased energy, emotional stability and memory These results were part of a total hormonal replacement program and grading was based on each individuals own subjective response and evaluation. Uniformly, the responses showed improved scores in all categories based on the 212 participants' own ratings. Other studies since then have shown additional benefits: * Improved lipid picture - elevates HDL and lowers LDL * Effects on bone strength * Improved cardiovascular strength * Improved lung, kidney, liver, and spleen function * Improved sleep * Improved mental functioning and memory U.S. HGH PRODUCT
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