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Calcium exchanges in two neotenic urodeles: Necturus maculosus and Ambystoma tigrinum. Role of the integument

1981; Elsevier BV; Volume: 70; Issue: 1 Linguagem: Inglês

10.1016/0300-9629(81)90395-9

0300-9629

Geraldine F. Baldwin, P.J. Bentley,

Physiological and biochemical adaptations

1. We have measured calcium exchanges across the integument of two neotenous urodele amphibians, mudpuppies, (Necturus maculosus) and tiger salamanders (Ambystoma tigrinum). We also studied adult tiger salamanders. 2. The integument was permeable to Ca, both an uptake and loss of the mineral may occur. In fasting mudpuppies and adult tiger salamanders integumental and urinary loss of Ca were similar to each other. The total Ca loss each day was equivalent to less than 0.5% of the total body calcium, though it represents 35 to 50% of the amount of Ca in the extracellular fluids. 3. Unidirectional fluxes of Ca (influx and efflux) across the skin of the mudpuppy were similar (in vitro) suggesting that an active transport of Ca is not occurring. 4. The permeability of the external gills of the neotenous animals appeared to be very low compared to that of the skin; there was no change in accumulation of 45Ca (in vivo) when the gills were ligated.