The effect of metals on the S-S polypeptide receptor in depolarized rat uterus.
1. Metals potentiate the contractile effects of S-S polypeptides in depolarized rat uterus. Their order of potency is Co(++)>/=Co(+++)>/=Mn(++)>/=Ni(++)>/= Mn(+++)>Zn(++)>/=Mg(++)>Fe(++)>Fe(+++)>/= Ca(++)>Be(++)=Sr(++)=Ba(++)=Cu(++)=O.2. S-S polypeptides with relatively weak oxytocic activity such as lys-vasopressin, arg-vasopressin and orn-vasopressin are strongly potentiated by metals while highly active polypeptides such as oxytocin are weakly potentiated.3. Potentiation by metals was specific for S-S polypeptides; other polypeptides (bradykinin, hypertensin) as well as acetylcholine and isoprenaline were unaffected.4. Potentiation by metals occurs rapidly and is fully reversible. In all cases some activity was retained by S-S polypeptides even in the complete absence of metals.5. A scheme which could account for the observed effects has been formulated. This assumes the formation of a ternary complex between receptor, metal and polypeptide leading to improved alignment between polypeptide and receptor.6. Analogies are discussed between metal enzymes and the S-S polypeptide receptor for which the term metal receptor is proposed.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D001608:Beryllium / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology*; D009532:Nickel / Q000494:pharmacology; D010121:Oxytocin / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D013324:Strontium / Q000494:pharmacology; D014599:Uterus / Q000187:drug effects*; D014667:Vasopressins / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology
D008670:Metals; D010455:Peptides; D014667:Vasopressins; D000804:Angiotensin II; D001464:Barium; D003035:Cobalt; D008345:Manganese; D010121:Oxytocin; D003300:Copper; D009532:Nickel; D007501:Iron; D008274:Magnesium; D015032:Zinc; D001608:Beryllium; D001920:Bradykinin; D002118:Calcium; D013324:Strontium