The Physiology of the Antennal Gland of Carcinus Maenas (L.)

Abstract

1. Amino acids are actively reabsorbed by the antennal gland of Carcinus in all concentrations of sea water, but there is never complete recovery of these molecules from the urine; even in animals in 100% sea water amino acids are eliminated in the urine. 2. The urine concentration of amino acids is related to (i) the blood amino acid concentration and (ii) the rate of urine production. An increase in either or both of these factors, for example, when animals are in dilute sea water, raises the U/B ratio of amino acids. 3. The rate of reabsorption of amino acids increases as the amino acid load on the antennal gland is raised. When reabsorption is maximal, the rate of transport is about seven times greater than at normal concentrations of amino acids in blood and urine when the animal is in 100% sea water. 4. Increases in blood amino acid concentrations when crabs are placed directly into dilute sea water are taken to be the result of changes in free amino acids of muscle which occur under these conditions. This intracellular regulation in dilute media is initiated when the blood sodium concentration is approximately 400 mM/l.