Drug Bytes
By Steve Blechman and Thomas Fahey, EdD

Researchers Blast Growth Hormone for Anti-aging
More than 30,000 Americans use growth hormone (GH) as an anti-aging therapy. The hormone reportedly increases lean mass, decreases fat, improves skin texture, strengthens connective tissue, boosts sex drive and improves the quality of life. Researchers from Stanford University, in a review of literature, criticized growth hormone supplementation for older adults. They examined 18 studies involving 220 overweight men and women, with an average age of 69. People lost an average of 5 pounds of fat and gained 5 pounds of lean body mass in 27 weeks, but noted no changes in bone density or blood fat levels. Growth hormone therapy has side effects such as swelling, joint pain, carpal tunnel syndrome (wrist numbness) and gynecomastia (breast enlargement). Some subjects developed insulin resistance and elevated blood sugar, which typically disappears after the first few months of treatment. This was a very negative, biased paper. They didn’t mention several very important studies and didn’t consider the cumulative benefits of GH therapy combined with exercise and diet. GH allows older adults to exercise harder and get greater benefits from exercise. The body composition changes were remarkable in older people, who usually experience decreases in lean mass and increases in body fat. Our interpretation of the literature is that growth hormone supplementation is viable and improves the quality of life in older adults. (Annals Internal Medicine, 146:104-115, 2007)

SARMs Next Generation of Anabolics
The next generation of anabolic drugs will be selective androgen receptor modulators (SARMs), which target androgen receptors in specific tissues, such as muscle or bone. SARMs are the Holy Grail of anabolic chemicals because they’ll build muscles without affecting other organs or tissues. Dr. Elizabeth Wilson from the University of North Carolina discussed a new SARM called BMS-564929 that selectively targets skeletal muscle but does not affect the liver or prostate. Muscle-focused SARMs will be of great interest to older adults experiencing bone or muscle loss, patients suffering from trauma or degenerative diseases, or athletes trying to improve performance. Researchers from five different companies are conducting clinical trials on SARMs, but it will be at least four years before the Food and Drug Administration approves them. The drugs exist, so it’s likely athletes will use them in the next Olympic games. (Endocrinology, 148: 1-3, 2007)

Steroid Users Show Early Evidence of Heart Distress
Heavy weightlifting increases the size of the heart. Anabolic steroids boost strength, which allow athletes to train harder and lift more weight. It should come as no surprise that steroid users often have enlarged hearts because they’re stronger, push heavier weights and thus, stress the heart more. Italian researchers, using a technique called Doppler myocardial imaging (DMI), noted that chronic steroid abusers showed “subclinical” signs of systolic and diastolic distressed heart muscle function. Systolic (systole) refers to the part of the cardiac cycle when the heart is contracting and pumping blood, while diastolic (diastole) occurs when the heart is relaxing and filling. The heart has to work harder as the heart size increases. A small increase in heart size leads to a large increase in the tension necessary to contract the heart. Fortunately, heart size decreases when athletes stop weight training and taking steroids. However, lifelong training and anabolic steroid drug use could damage the heart. (British Journal Sports Medicine, in press; published online Dec. 18, 2006)

Growth Hormone Stimulator Increases GH & IGF-1
Growth hormone (GH) is an extremely anabolic hormone that promotes muscle and bone growth and cuts fat. Training-induced increases in GH are correlated to gains in muscle mass and strength. Growth hormone exerts these anabolic effects by producing IGF-1 in the liver, which is a potent muscle growth factor. The body releases GH impulses, which is important for maintaining the GH concentration in the blood and promoting its anabolic effects. GH levels and pulsing decrease markedly in older adults. Researchers from the University of Illinois found that administering gonadotropin-releasing hormone, a GH controlling chemical normally produced in the hypothalamus of the brain, increased GHB and IGF production and maintained normal GH pulsing. This drug may be an inexpensive, effective and a safe alternative to GH injections for promoting bone and muscle growth. (Journal Clinical Endocrinology Metabolism, 91: 4792-4797, 2006)

SARMs Build Muscle & Bone Without Affecting the Prostate
Selective androgen receptor modulators (SARMs) are drugs that bind to the androgen receptors, which turn on protein synthesis in the nucleus of cells. Hormones, such as testosterone, work by binding to specific receptors. The hormone-receptor complex enters the cell nucleus and turns on protein synthesis in the cell. A problem with testosterone (and other anabolic steroids) is that it binds to androgen receptors in cells throughout the body— not just muscle cells. Testosterone builds muscle but also binds to receptors in the prostate, sex organs and skin, which cause unwanted effects. Unlike testosterone or other anabolic steroids, SARMs have focused anabolic activity on bone and muscle without affecting the prostate or skin and are safe if taken orally. Researchers from Ligand Pharmaceuticals in San Diego developed a SARM (LGD2226) that triggers anabolic action in muscle and bone without affecting the prostate gland. The drug isn’t a steroid, doesn’t aromatize to estrogen and specifically targets receptors in muscle and bone. SARMs are in the first stages of development but could have a major impact in treating bone and muscle deterioration in aging adults and in people with degenerative diseases— with far fewer side effects. Undoubtedly, bodybuilders and power athletes will be very interested in these drugs. (Endocrinology, in press; published online Oct. 5, 2006)

Growth Hormone Improves Cardiac Function in Heart Failure
Heart failure (also called congestive heart failure, CHF) is a disabling condition in which the heart can’t meet the body’s demand for blood. CHF causes blood backup in the veins, increased heart chamber size, swelling in the lower body, reduced exercise capacity, fatigue and shortness of breath. Growth hormone is a viable treatment for heart failure patients. French researchers, combining the results of 12 studies using a technique called meta-analysis, found that growth hormone improves heart function in patients with congestive heart failure. Treated patients showed decreased chamber size and wall thicknesses in the heart, reduced measures of heart stress and increased blood pressure. Most growth hormone-heart failure studies used few subjects, so we need large population studies to assess the effectiveness of this drug on these patients. (Journal Clinical Endocrinology Metabolism, 92: 180-185, 2007)

Does Growth Hormone Cause Cancer?
Growth hormone is a highly anabolic chemical that stimulates cell growth throughout the body. It also triggers the release of other anabolic substances, such as insulin-like growth factors. Growth hormone is very popular among older adults and athletes, who take it to increase muscle mass, decrease fat and strengthen connective tissue. The drug effectively promotes growth in tissues throughout the body, but it also has the potential to stimulate and promote cancer cell development and growth. Researchers from New Zealand, in a review of literature, summarized the theoretical link between growth hormone and cancer. Studies in animals and tissue cultures (stimulated cancer cells in test tubes) showed that growth hormone might promote and speed the progression of breast cancer cells. This study put the cart before the horse: no epidemiological study has shown a link between growth hormone supplementation and increased cancer risk. It makes little sense to suggest a mechanism for a health problem that may not exist. (Growth Hormone IGF Research, 16: 277-289, 2006)

Clenbuterol Stimulates Protein Synthesis
Clenbuterol is a beta-adrenergic receptor agonist that promotes the action of fight-or-flight hormones like epinephrine (adrenaline). Physicians use it to treat lung problems such as asthma. Bodybuilders have known for years that the drug increases muscle mass, but scientists don’t know how it works. Researchers from the Iowa State University found that clenbuterol activates genes regulating messenger RNA (mRNA) in muscle, which helps code Amino Acids sequences in protein synthesis. The mRNAs help develop satellite cells in muscle fibers that promote muscle hypertrophy (growth). The general arousal stemming from clenbuterol administration is similar to the effect of exercise and sheds new light on the way muscles grow. (BMC Genomics, in press; published online Dec. 20, 2006)