Insulin, growth hormone and sport
P H Sonksen
Abstract
This review examines some interesting ‘new’ histories of insulin and reviews our current understanding of its physiological actions and synergy with GH in the regulation of metabolism and body composition. It reviews the history of
GH abuse that antedates by many years the awareness of endocrinologists to its potent anabolic actions. Promising methods for detection of GH abuse have been developed but have yet to be succinctly well validated to be ready for introduction into competitive sport. So far, there are two promising avenues for detecting GH abuse.
The first uses immunoassays that can distinguish the isomers of pituitary-derived GH from the monomer of recombinant human GH. The second works through demonstrating circulating concentrations of one or more GH-sensitive substances that exceed the extremes of normal physiological variability. Both methods require blood rather than urine samples. The first method has a window of opportunity lasting about 24 h after an injection and is most suitable for ‘out of competition’ testing.
The second method has reasonable sensitivity for as long as 2 weeks after the last injection of GH and is uninfluenced by extreme exercise and suitable for post-competition samples. This method has a greater sensitivity in men than in women. The specificity of both methods seems accept- ably high but lawyers need to decide what level of scientific probability is needed to obtain a conviction. Both methods need further validation before implementation.
Research work carried out as part of the fight against doping in sport has opened up a new and exciting area of endocrinology. Journal of Endocrinology (2001) 170, 13–25
Introduction
Doping in sport has a very long history going as far back as the original Olympic Games and is mainly driven by the desire to win at all cost. In order to maintain an environment where cheats do not win, it is essential to develop methods of combating abuse of performance-enhancing drugs. To this end the International Olympic Committee (IOC) Medical Commission and Sub-Commission
‘Doping and Biochemistry in Sport’ publish annually a list of ‘banned substances’ and have developed a sophisticated system for detecting drug abuse. Recent evidence indicates that the protein hormones insulin and growth hormone (GH) have now become a significant threat to the level playing field essential in sport. The IOC was swift to ban GH and insulin but no tests are available to detect their abuse. As endogenous substances secreted in bursts they pose particular problems in developing satisfactory methods of detection. Our understanding of how insulin and GH work in the regulation of metabolism and body composition has evolved to demonstrate a remarkable degree of synergy, something the athletes may have discovered before the endocrinologists.
GH has been used as a drug of abuse in sport since the early 1980s – 10 years before endocrinologists recognized and understood its potency as an anabolic agent and as a hormone regulating body composition in adults. Insulin appears to have a shorter history as a ‘doping agent’ – it was at the Winter Olympic Games in Nagano in 1998 when a Russian medical o.cer enquired as to whether the use of insulin was restricted to insulin-dependent diabetes.
This drew attention to its role as a potential performance-enhancing drug and the IOC were swift to act and immediately placed it on its list of banned substances.
Subsequent evidence from a needle-exchange program in the UK (R T Dawson, personal communication) has confirmed its widespread use in body building and other sports although it remains unclear exactly how it is used.
This review presents a brief but important (and not very well-known) history of the physiology of insulin that is essential for understanding the way in which it is used as a performance-enhancing agent. It points out how, some- what paradoxically, the advances of ‘modern science’, through inappropriate extrapolation from in vitro to in vivo, confused the thinking and teaching to hide the truth behind insulin action right up to the present day!
P H Sonksen
Abstract
This review examines some interesting ‘new’ histories of insulin and reviews our current understanding of its physiological actions and synergy with GH in the regulation of metabolism and body composition. It reviews the history of
GH abuse that antedates by many years the awareness of endocrinologists to its potent anabolic actions. Promising methods for detection of GH abuse have been developed but have yet to be succinctly well validated to be ready for introduction into competitive sport. So far, there are two promising avenues for detecting GH abuse.
The first uses immunoassays that can distinguish the isomers of pituitary-derived GH from the monomer of recombinant human GH. The second works through demonstrating circulating concentrations of one or more GH-sensitive substances that exceed the extremes of normal physiological variability. Both methods require blood rather than urine samples. The first method has a window of opportunity lasting about 24 h after an injection and is most suitable for ‘out of competition’ testing.
The second method has reasonable sensitivity for as long as 2 weeks after the last injection of GH and is uninfluenced by extreme exercise and suitable for post-competition samples. This method has a greater sensitivity in men than in women. The specificity of both methods seems accept- ably high but lawyers need to decide what level of scientific probability is needed to obtain a conviction. Both methods need further validation before implementation.
Research work carried out as part of the fight against doping in sport has opened up a new and exciting area of endocrinology. Journal of Endocrinology (2001) 170, 13–25
Introduction
Doping in sport has a very long history going as far back as the original Olympic Games and is mainly driven by the desire to win at all cost. In order to maintain an environment where cheats do not win, it is essential to develop methods of combating abuse of performance-enhancing drugs. To this end the International Olympic Committee (IOC) Medical Commission and Sub-Commission
‘Doping and Biochemistry in Sport’ publish annually a list of ‘banned substances’ and have developed a sophisticated system for detecting drug abuse. Recent evidence indicates that the protein hormones insulin and growth hormone (GH) have now become a significant threat to the level playing field essential in sport. The IOC was swift to ban GH and insulin but no tests are available to detect their abuse. As endogenous substances secreted in bursts they pose particular problems in developing satisfactory methods of detection. Our understanding of how insulin and GH work in the regulation of metabolism and body composition has evolved to demonstrate a remarkable degree of synergy, something the athletes may have discovered before the endocrinologists.
GH has been used as a drug of abuse in sport since the early 1980s – 10 years before endocrinologists recognized and understood its potency as an anabolic agent and as a hormone regulating body composition in adults. Insulin appears to have a shorter history as a ‘doping agent’ – it was at the Winter Olympic Games in Nagano in 1998 when a Russian medical o.cer enquired as to whether the use of insulin was restricted to insulin-dependent diabetes.
This drew attention to its role as a potential performance-enhancing drug and the IOC were swift to act and immediately placed it on its list of banned substances.
Subsequent evidence from a needle-exchange program in the UK (R T Dawson, personal communication) has confirmed its widespread use in body building and other sports although it remains unclear exactly how it is used.
This review presents a brief but important (and not very well-known) history of the physiology of insulin that is essential for understanding the way in which it is used as a performance-enhancing agent. It points out how, some- what paradoxically, the advances of ‘modern science’, through inappropriate extrapolation from in vitro to in vivo, confused the thinking and teaching to hide the truth behind insulin action right up to the present day!
via World Class Bodybuilding Forum http://www.worldclassbodybuilding.com/forums/f485/insulin-growth-hormone-and-sport-138609/
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