Study summary · research use only
Detection of black market follistatin 344
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This study (species not specified; analytical detection-method development) investigated black market products labeled follistatin 344 (FS344) and follistatin 315, prohibited under the WADA 2019 List, developing an electrophoretic detection method for serum and urine. Of 17 tested products, the abstract reports that only nine actually contained follistatin, with some others containing growth-promoting peptides such as MGF and GHRP-2; all nine follistatin-containing products contained His-tagged FS344 with a high degree of oligomers. Detection used immunomagnetic purification followed by SDS-PAGE and Western blotting with a monoclonal anti-His antibody, or alternatively an anti-follistatin antibody. The abstract reports a detection limit of about 0.1 ng/mL for a 10 mL urine sample and 5 ng/mL for a 100 μL serum sample, with His-tags allowing differentiation from endogenous follistatin.
Abstract
Follistatin, a myostatin-inhibiting protein, is prohibited according to chapter S4 of the "WADA 2019 List of Prohibited Substances and Methods". While currently no approved pharmaceutical formulations of follistatin are available, follistatin can be bought on the black market. Most of the products are labeled "follistatin 344" (FS344), a few "follistatin 315". A study on FS344 black market products was performed and an electrophoretic detection method for serum and urine developed. While only nine of the 17 tested products actually contained follistatin, in some of the others growth promoting peptides were found (e.g. MGF, GHRP-2). Surprisingly, all nine products contained His-tagged FS344 and a high degree of its oligomers. The detection method is based on immunomagnetic purification followed by SDS-PAGE and Western blotting with a monoclonal anti-His antibody. Alternatively, a monoclonal anti-follistatin antibody can be used. For immunoprecipitation (IP), a polyclonal anti-follistatin antibody is applied. An evaluation of suitable antibodies for IP and immunoblotting is also presented. Furthermore, practically all currently available follistatin standards were investigated. The detection limit of the method for black market FS344 in urine is ca 0.1 ng/mL for 10 mL. For a sample volume of 100 μL, an LOD of 5 ng/mL could be achieved for serum. Due to the presence of His-tags an unambiguous differentiation from endogenous follistatin is possible.
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