Measurement of Na-K-atpase in the separated epidermis of Rana catesbeiana frogs and tadpoles

Abstract

1. 1. Ventral skin of Rana pipiens and R. catesbeiana frogs and R. catesbeiana tadpoles was readily separated into dermal and epidermal sheets after soaking for brief periods in 0·5–2 N solutions of sodium, potassium or ammonium iodide or bromide but not chloride. 2. 2. Transport-associated Na-K-ATPase was consistently measurable in epidermal homogenates (in contrast to homogenates prepared from whole skin) even though the electrical indications of active sodium transport were lost during the separation process. 3. 3. Levels of Na-K-ATPase in the epidermis of premetamorphic bullfrog tadpoles were only a quarter to a third of the levels measured in epidermis from adult bullfrogs. The failure of isolated premetamorphic tadpole skin to actively transport sodium may be related to this deficiency.