title: Active transport of calcium ions in the skin of the salamander Ambystoma tigrinum.
abstract: We measured Ca2+ exchanges across the skin of larval and adult Ambystoma tigrinum using the radio-isotope influx method. We found that the skin of both morphs takes up Ca2+ in a manner that is proportional to external [Ca2+], saturable and oriented against the electrochemical gradient for Ca2+. We conclude that this uptake occurs by active transport. Kinetic analysis yields affinities for calcium ions that are similar to the affinities for both Ca2+ and Na+ in the skin of other amphibians. The capacity for calcium is similar to Ca2+ capacity in other amphibians. The capacity for Ca2+ is lower than the capacity for Na+. Cutaneous Ca2+ deposits are lower in this urodele than found in anurans. Adults tend to have higher levels of Ca in their skin than do larvae.
authors.affiliation: Biological Sciences Department, California State Polytechnic University, Pomona 91768, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Zerella
authors.forename: D F
authors.initials: DF
authors.lastname: Stiffler
mesh_terms: D000367:Age Factors; D000557:Ambystoma / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D002118:Calcium / Q000493:pharmacokinetics*; D005618:Fresh Water; D007700:Kinetics; D007814:Larva / Q000502:physiology; D008675:Metamorphosis, Biological / Q000502:physiology; D011522:Protons; D012867:Skin / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism
chemical_list: D011522:Protons; D012964:Sodium; D002118:Calcium