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majutsu
Well-known member
There is a new study where rats infected with a virus that feeds multiple RNA copies of IGF into the biochemical machinery, meaning that the animals have a "cold" but produce tons of IGF instead of "snot", grow tremendous mass with resistance training. Does anyone have anecdotal evidence about IGF administration?
Here's the study -- it's fascinating:
J Appl Physiol. 2004 Mar;96(3):1097-104. Related Articles, Links
Viral expression of insulin-like growth factor-I enhances muscle hypertrophy in resistance-trained rats.
Lee S, Barton ER, Sweeney HL, Farrar RP.
Dept. of Physiology, Univ. of Pennsylvania, B400 Richards Bldg., 3700 Hamilton Walk, Philadelphia, PA 19104. [email protected]
Muscle hypertrophy is the product of increased drive through protein synthetic pathways and the incorporation of newly divided satellite cells. Gains in muscle mass and strength can be achieved through exercise regimens that include resistance training. Increased insulin-like growth factor-I (IGF-I) can also promote hypertrophy through increased protein synthesis and satellite cell proliferation. However, it is not known whether the combined effect of IGF-I and resistance training results in an additive hypertrophic response. Therefore, rats in which viral administration of IGF-I was directed to one limb were subjected to ladder climbing to test the interaction of each intervention on muscle mass and strength. After 8 wk of resistance training, a 23.3% increase in muscle mass and a 14.4% increase in peak tetanic tension (P(o)) were observed in the flexor hallucis longus (FHL). Viral expression of IGF-I without resistance training produced a 14.8% increase in mass and a 16.6% increase in P(o) in the FHL. The combined interventions produced a 31.8% increase in muscle mass and a 28.3% increase in P(o) in the FHL. Therefore, the combination of resistance training and overexpression of IGF-I induced greater hypertrophy than either treatment alone. The effect of increased IGF-I expression on the loss of muscle mass associated with detraining was also addressed. FHL muscles treated with IGF-I lost only 4.8% after detraining, whereas the untreated FHL lost 8.3% muscle mass. These results suggest that a combination of resistance training and overexpression of IGF-I could be an effective measure for attenuating the loss of training-induced adaptations.
Here's the study -- it's fascinating:
J Appl Physiol. 2004 Mar;96(3):1097-104. Related Articles, Links
Viral expression of insulin-like growth factor-I enhances muscle hypertrophy in resistance-trained rats.
Lee S, Barton ER, Sweeney HL, Farrar RP.
Dept. of Physiology, Univ. of Pennsylvania, B400 Richards Bldg., 3700 Hamilton Walk, Philadelphia, PA 19104. [email protected]
Muscle hypertrophy is the product of increased drive through protein synthetic pathways and the incorporation of newly divided satellite cells. Gains in muscle mass and strength can be achieved through exercise regimens that include resistance training. Increased insulin-like growth factor-I (IGF-I) can also promote hypertrophy through increased protein synthesis and satellite cell proliferation. However, it is not known whether the combined effect of IGF-I and resistance training results in an additive hypertrophic response. Therefore, rats in which viral administration of IGF-I was directed to one limb were subjected to ladder climbing to test the interaction of each intervention on muscle mass and strength. After 8 wk of resistance training, a 23.3% increase in muscle mass and a 14.4% increase in peak tetanic tension (P(o)) were observed in the flexor hallucis longus (FHL). Viral expression of IGF-I without resistance training produced a 14.8% increase in mass and a 16.6% increase in P(o) in the FHL. The combined interventions produced a 31.8% increase in muscle mass and a 28.3% increase in P(o) in the FHL. Therefore, the combination of resistance training and overexpression of IGF-I induced greater hypertrophy than either treatment alone. The effect of increased IGF-I expression on the loss of muscle mass associated with detraining was also addressed. FHL muscles treated with IGF-I lost only 4.8% after detraining, whereas the untreated FHL lost 8.3% muscle mass. These results suggest that a combination of resistance training and overexpression of IGF-I could be an effective measure for attenuating the loss of training-induced adaptations.
