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The comparison drugs are included because the paper measured them together, not as a metformin claim.\nexposure: Metformin 30 mmol/l in homogenates and 270 micromol/l for 24 h in intact muscle, compared with thiazolidinediones\nevidence_span: {\"source_cache\": \"artifacts/metformin-research/15047621.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"c4c648ab82a982482ec339309f3cc1c84ffe457073f010b546f7a47ffa2fbdf6\", \"start_char\": 0, \"end_char\": 1613, \"text_sha256\": \"c4c648ab82a982482ec339309f3cc1c84ffe457073f010b546f7a47ffa2fbdf6\"}\n[metformin-p15047621] Thiazolidinediones, like metformin, inhibit respiratory complex I: a common mechanism contributing to their antidiabetic actions? 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