Ingestion and assimilation of dissolved amino acids by a starfish

Abstract

1. 1. Levels of free amino acids were measured in the digestive glands of groups of the Tampa Bay starfish. Echinaster, for 10 days following their ingestion of a dissolved amino acid mixture (casein hydrolysate). Similar measurements were made on unfed controls. 2. 2. Ingestion produced a significant elevation of the tissue free amino acid pool level to over twice the control level. This increase mostly represented an accumulation and concentration of the specific ingested amino acids to levels generally 20–50 times above those of the initial medium. The elevated levels diminished only slowly, and were still significant after 48 hr. 3. 3. The prolonged elevation of digestive gland amino acid pools following feeding may be expected to enhance coelomic translocation of amino acids to other body regions. 4. 4. Glycine and taurine levels, always high. did not change significantly with the ingestion. Some decline in glycine levels in unfed controls suggests metabolic utilization of this metabolite with starvation.