Aromatase inhibitors are anti-anabolic in rodent study
by Anthony Roberts
Within the steroid using community, it has become a well established fact that estrogen helps promote weight and strength gain. Steroids that don???t convert to estrogen (non-aromatizing compounds) typically do not provide the same degree of results as those which have some conversion to estrogen. We see this further proven by anti-estrogenic compounds, such as aromatase inhibitors, which, when added into a cycle, typically reduce gains. Estrogen, therefore, is anabolic, and compounds that reduce it, can properly be termed as anti-anabolic.
Remember, when something is anti-anabolic, it impairs the building of new tissue, as opposed to catabolic, which actually breaks tissue down.
Now, a recently published study has provided evidence of impaired body weight gain (an anti-anabolic effect), in male rodents given exemestane, a suicidal aromatase inhibitor:
Horm Res Paediatr. 2010;73(5):376-85. Epub 2010 Apr 14.
Impaired body weight and tail length gain and altered bone quality after treatment with the aromatase inhibitor exemestane in male rats.
van Gool SA, Wit JM, De Schutter T, De Clerck N, Postnov AA, Kremer Hovinga S, van Doorn J, Veiga SJ, Garcia-Segura LM, Karperien M.
Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands. s.van_gool @ lumc.nl
Abstract
Background: Estrogen deficiency induced by aromatase inhibitors may be a novel treatment modality for growth enhancement in short children, but may have adverse effects on bone, brain and reproduction. Aim: To assess growth effects and potential adverse effects of aromatase inhibition in male rats. Methods: 26-day-old prepubertal rats received intramuscular injections with placebo or the aromatase inhibitor exemestane at a dose of 10, 30 or 100 mg/kg/week [E10, E30, E100(6)] for 6 weeks, completely covering the sexual maturation phase, or with 3 weeks E100 followed by 3 weeks placebo [E100(3)]. Growth parameters and histology of the testis, seminal vesicle and brain were analyzed. Bone architecture was studied with X-ray microtomography. Results: Exemestane dose-dependently decreased body weight and tail length gain, as well as liver and seminal vesicle weights, but did not affect nose-anus length gain, growth plate width or radial growth. E100(6) decreased trabecular thickness (epiphysis and metaphysis) and number (metaphysis). Normal IGF-I levels and brain, testis and seminal vesicle morphology were observed. E100(3) resulted in decreased tail length gain only. Conclusion: Exemestane treatment during sexual maturation did not augment linear growth in male rats, but caused impaired body weight and tail length gain and osteopenia.
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by Anthony Roberts
Within the steroid using community, it has become a well established fact that estrogen helps promote weight and strength gain. Steroids that don???t convert to estrogen (non-aromatizing compounds) typically do not provide the same degree of results as those which have some conversion to estrogen. We see this further proven by anti-estrogenic compounds, such as aromatase inhibitors, which, when added into a cycle, typically reduce gains. Estrogen, therefore, is anabolic, and compounds that reduce it, can properly be termed as anti-anabolic.
Remember, when something is anti-anabolic, it impairs the building of new tissue, as opposed to catabolic, which actually breaks tissue down.
Now, a recently published study has provided evidence of impaired body weight gain (an anti-anabolic effect), in male rodents given exemestane, a suicidal aromatase inhibitor:
Horm Res Paediatr. 2010;73(5):376-85. Epub 2010 Apr 14.
Impaired body weight and tail length gain and altered bone quality after treatment with the aromatase inhibitor exemestane in male rats.
van Gool SA, Wit JM, De Schutter T, De Clerck N, Postnov AA, Kremer Hovinga S, van Doorn J, Veiga SJ, Garcia-Segura LM, Karperien M.
Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands. s.van_gool @ lumc.nl
Abstract
Background: Estrogen deficiency induced by aromatase inhibitors may be a novel treatment modality for growth enhancement in short children, but may have adverse effects on bone, brain and reproduction. Aim: To assess growth effects and potential adverse effects of aromatase inhibition in male rats. Methods: 26-day-old prepubertal rats received intramuscular injections with placebo or the aromatase inhibitor exemestane at a dose of 10, 30 or 100 mg/kg/week [E10, E30, E100(6)] for 6 weeks, completely covering the sexual maturation phase, or with 3 weeks E100 followed by 3 weeks placebo [E100(3)]. Growth parameters and histology of the testis, seminal vesicle and brain were analyzed. Bone architecture was studied with X-ray microtomography. Results: Exemestane dose-dependently decreased body weight and tail length gain, as well as liver and seminal vesicle weights, but did not affect nose-anus length gain, growth plate width or radial growth. E100(6) decreased trabecular thickness (epiphysis and metaphysis) and number (metaphysis). Normal IGF-I levels and brain, testis and seminal vesicle morphology were observed. E100(3) resulted in decreased tail length gain only. Conclusion: Exemestane treatment during sexual maturation did not augment linear growth in male rats, but caused impaired body weight and tail length gain and osteopenia.
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