Specificity of L-Alanine Transport in the Spine Epithelium of <i>Paracentrotus Lividus</i> (Echinoidea)

Abstract

In many marine invertebrates the presence of an active transport system for the epithelial absorption of amino acids has been conclusively demonstrated (Stephens, 1968. 1972; West, de Burgh &amp; Jeal, 1977). It has been observed by several authors that inhibition of uptake of a given amino acid can occur in the presence of other amino acids, in a manner analogous to that observed in vertebrate gut absorption systems. Some examples are the work of Chapman &amp; Taylor (1969) on whole Nereis virens, Ferguson (1968) on the digestive glands of Echinaster spinulosus , Ferguson (1971) on whole asteroids, Bamford &amp; Stewart (1973 a, b) on Arenicola marina gut, and Bamford &amp; McCrea (1975) on the gill of Cerastoderma edule .