title: The effect of EDTA and metal cations on the 5-bromoindoxyl acetate esterase activity in the thyroid of the guinea pig.
abstract: Miscellaneous metal cations and EDTA have been used as activators and inhibitors of esterase activity in the thyroid of the guinea-pig. The results indicate that the 5-bromoiondoxyl acetate esterase in the epithelial cells probably consists of two different A-esterase isoenzymes, one present in group I cells (the para-, intra-, and inter-follicular cells) and the other in group II cells (the follicular cells proper). The first isoenzyme seems to be calcium-dependent whereas the other is activated by various metal ions. Ca2+ + Mn2+ and Ca2+ + Co2+ were found to activate the esterase activity in group I cells. EDTA and Mn2+, on the other hand, activated the esterase activity in group II cells.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004950:Esterases / Q000378:metabolism*; D006168:Guinea Pigs; D006651:Histocytochemistry; D008274:Magnesium / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology*; D013194:Staining and Labeling; D013961:Thyroid Gland / Q000201:enzymology* / Q000648:ultrastructure; D015032:Zinc / Q000494:pharmacology*
chemical_list: D003035:Cobalt; D008345:Manganese; D004492:Edetic Acid; D004950:Esterases; D008274:Magnesium; D015032:Zinc; D002118:Calcium