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(1985). https://pubmed.ncbi.nlm.nih.gov/3968585/ DOI: 10.1093/jn/115.2.159","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Small-intestinal mucosa and portal effluent","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f5982dab-400e-55ce-9ca3-0e1fcddc8616","evidence_kind":"source_excerpt","locator":"Lines 943-955","start_line":943,"end_line":955,"excerpt":"### zn-sig-mt-binding-not-absorption\nAfter the tested dietary conditioning, high zinc increased metallothionein-bound copper without changing intracellular copper concentration or significantly altering measured copper absorption in the perfused intestine.\nCondition category: normal\nnutrient_topic: Zinc research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: More copper on a binding protein did not always mean less copper absorption.\norganism: Rattus norvegicus\ntissue_or_cell_type: Small-intestinal mucosa and portal effluent\nexperimental_model: Isolated vascularly perfused intestine from diet-conditioned rats\nlimitations: Ex-vivo perfusion and extreme luminal exposure differ from whole-animal feeding; increased metallothionein-bound copper alone did not prove reduced net absorption.\nexposure: Dietary copper/zinc variation for one week versus direct luminal-metal variation.\ncross_nutrient: Copper (affected_nutrient); Intestinal copper absorption (unchanged_endpoint); Rat intestinal metallothioneins measured without isoform resolution (binding_proteins)\nevidence_span: {\"source_cache\": \"artifacts/zinc-signaling-sources/3968585-abstract.txt\", \"locator\": \"Primary indexed abstract\", \"file_sha256\": \"ca588cec5326d23dd5f8c9b409ea66fc415043b95af456399e495b8131c8f6ed\"}\n[zn-sig-3968585] Copper and zinc absorption in the rat: mechanism of mutual antagonism. 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