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Influence of Dietary Supplements on Body Composition
Published in Henry C. Lukaski, Body Composition, 2017
Sympathomimetic drugs including so called nutrient partitioning agents developed for meat production also found their way into human use, with athletes testing positive for clenbuterol use at various international competitions (Ricks et al. 1984; Rothwell and Stock 1985; Prather et al. 1995). In the push for new antiobesity drugs, beta-3 agonists have been considered. However, the paucity of beta-3 receptors and the role of brown adipose tissue in weight management in humans are still poorly understood and differ from the responses of another species (Weyer et al. 1999). This would presumably be more desirable than the beta-2 agonists which have significant chronotropic and other undesirable cardiovascular effects (Huckins and Lemons 2013). The beta-2 agonists are approved for human use in the United States in inhaled form because they provide significant benefits to asthmatics; these doses and formulations may not produce the body composition changes that have been anecdotally reported with higher doses in oral form used by body builders and athletes. There may even be antagonistic effects of exercise on the clenbuterol-stimulated increase in muscle mass (Kearns et al. 2001). In animal studies, the beta-2 agonists promote protein accretion primarily through suppression of protein degradation (Costelli et al. 1995), and also accelerate fat metabolism (Kearns et al. 2001). This suggests therapeutic potential at least in human applications for cancer cachexia and aging-related muscle wasting. Only anecdotal data exists for human body composition and physical performance effects.
Power and power endurance: the explosive sports
Published in Nick Draper, Helen Marshall, Exercise Physiology, 2014
Prior to examining the ergogenic effects of creatine monohydrate, a legal nutritional supplement, it is worth highlighting the case of clenbuterol which is associated with increased muscle mass and decreased fat mass. Clenbuterol is associated with anabolic steroids, because, in the past, athletes took it in place of steroids in the final weeks before competition to maintain the anabolic effects, but avoid the risks of a positive steroid test. It is also interesting to examine the case of clenbuterol, as it is one of the β2 adrenergic-agonists that can be used in the treatment of asthma, which is one of the focuses of Chapter 14.
Supercritical Fluid Extraction as a Sample Preparation Tool in Analytical Toxicology
Published in Steven H. Y. Wong, Iraving Sunshine, Handbook of Analytical Therapeutic Drug Monitoring and Toxicology, 2017
Robert J. Maxwell, Janet F. Morrison
Other investigators have also experienced difficulties in extracting pharmaceuticals from freeze-dried or desiccated tissue samples. For example, Jimenez-Carmona et al.45 attempted to extract clen-buterol with unmodified SF-CO2 from lyophilized liver (20 μg/g) premixed with an ion-pairing reagent, the ammonium salt of camphorsulfonic acid. Clenbuterol is a β-adrenergic agonist that is used illegally in Europe and the U.S. as a growth promoter in meat-producing animals, and is monitored by both U.S. and European regulatory agencies. Using an SFE instrument containing a variable restrictor similar in design to that shown in Figure 5–3b, Jimenez-Carmona et al. obtained poor clenbuterol recoveries (12%) from the lyophilized liver samples. The authors provided no explanation for the low recoveries. Subsequent work by Parks et al.85 suggests that the difficulty may have been caused in part by the lack of water in the liver samples used by the previous investigators. Parks et al. used SF-CO2 for the isolation of the veterinary drug zoalene (3,5-dinitro-o-toluamide) from chicken liver. They found that dehydration of the sample matrix during SFE results in stronger adsorption of the analytes, thereby limiting their extractability. The authors demonstrated this effect by first extracting a liver sample containing no zoalene (SF-CO2, 60°C, 103 MPa). After SFE, the desiccated liver was recovered from the vessel, fortified with 2.0 μg/g of zoalene, mixed with Na2SO4, and reextracted under the same SFE conditions. Analysis of the resultant SFE extract indicated 42% of the zoalene was extracted from the desiccated matrix. The desiccated sample matrix was recovered from the extraction vessel, mixed with 0.85 ml water, and reextracted as before. This third reextraction resulted in an additional 46% recovery of zoalene for a combined yield of 88%. The total yield is about the same as that reported from nondesiccated tissue. This study confirms the critical role water plays in the SFE recovery of polar analytes from tissues.
Precision-cut liver slices as a model for assess hepatic cellular response of chitosan–glutathione nanoparticles on cultures treated with zilpaterol and clenbuterol
Published in Toxicology Mechanisms and Methods, 2022
Sofia Piña-Olmos, Mariana Dolores-Hernández, Roberto Diaz-Torres, J. Efrén Ramírez-Bribiesca, Raquel López-Arellano, Laura Denise López Barrera, Patricia Ramírez-Noguera
Zilpaterol and clenbuterol are two β-adrenergic agonists used to improve growth performance, feed efficiency, and carcass quality in cattle (Centner et al. 2014; Milford et al. 2019). While zilpaterol is a lawful drug for cattle feed in authorized countries (Choi et al. 2013; Cônsolo et al. 2016), clenbuterol is restricted for therapeutic applications. Both drugs have similar pharmacokinetic and pharmacodynamic (WHO and FAO 2016b, 2018c). However, their toxicokinetic and toxicodynamic are not well established. So, there are some toxicological concerns on animals and the risk population due to the misuse of these substances on animal feeding. When they are orally administrated in laboratory animals, domestic species, and humans (WHO and FAO 2016b), the target organs involved in the metabolism and excretion are the liver and kidneys (WHO and FAO 2014a); once these β-adrenergic reach the liver tissue, phases I and II reactions such as hydroxylation, n-oxidation, conjugation with sulfates and glucuronides occurs (Zalko et al. 1997; Alonen et al. 2009; Domínguez-Romero et al. 2013), some of these arisen substances could be toxic for hepatic cells by the formation of reactive oxygen species (ROS) or reactive nitrogen species (NOS), leading to oxide-reduction unbalance and cellular damage. Previous reports demonstrate that antioxidants such as ascorbic acid and reduced glutathione (GSH) prevent reactive metabolites formation during clenbuterol metabolism (Brambilla et al. 2007).
Enzyme replacement therapy for the treatment of Pompe disease
Published in Expert Opinion on Orphan Drugs, 2018
(2) ERT in combination with other drugs Alglucosidase alfa and miglustat (Federico II University of Naples, Italy)Amicus rhGAA (ATB200) and miglustat (AT2221) (Amicus Therapeutics)Alglucosidase alfa and albuterol (Duke University, United States). Albuterol was previously found effective with branched-chain aminoacids [62].Alglucosidase alfa and clenbuterol (Duke University, United States). Clenbuterol was found effective in murine Pompe disease [63].
The β2-adrenoceptor agonist clenbuterol reduces the neuroinflammatory response, neutrophil infiltration and apoptosis following intra-striatal IL-1β administration to rats
Published in Immunopharmacology and Immunotoxicology, 2018
Éadaoin W. Griffin, Justin D. Yssel, Eoin O’Neill, Katie J. Ryan, Noreen Boyle, Peter Harper, Andrew Harkin, Thomas Connor
A dose of clenbuterol (0.5 mg/kg) was used based on studies demonstrating that this dose has neuroprotective effects in a rat model of stroke19 and from previous studies in our laboratory where clenbuterol at doses up to 0.5 mg/kg were reported to have robust anti-inflammatory effects in the rat brain which we speculated may contribute to neuroprotective effects16,21,23,24. Maximal anti-inflammatory effects of clenbuterol are observed between 4- and 8-h post administration. Based on these experiments a single anti-inflammatory dose on the upper limb of the dose response curve was evaluated for neuroprotection in the current study. Clenbuterol (0.5 mg/kg; i.p.) was administered to rats one hour prior to intra-striatal microinjection of IL-1β (100 ng). Four-h post-injection rats were deeply anesthetized with a terminal injection of urethane. Heparinized blood samples were collected via cardiac puncture for whole blood cell counts, leukocyte differentiation and plasma chemokine analysis. Tissue was perfused with ice-cold heparinized saline and the ipsilateral striatum and liver tissue were harvested for mRNA expression analysis. NFκB activity (P65 binding) was measured by ELISA in nuclear extracts prepared from the striatum. Twenty-four-hours postinjection of IL-1β, the remaining animals were transcardially perfused with heparinized saline and 4% PFA in preparation for immunohistochemical detection of neutrophils and apoptosis analysis.