Osmoregulation of the grass shrimp Palaemonetes pugio exposed to polychlorinated biphenyls (PCBs), 2: Effect on free amino acids of muscle tissue

Glycine was the most abundant free amino acid (FAA) in abdominal muscle of P.pugio, accounting for>50% of the total pool. Arginine, alanine, proline, taurine and serine were also present at relatively high concns. Following transfer from 17 ppt to 2 and 32 pptS, new steady-state levels of total FAA were observed at 72 h. Total FAA and the sum of glycine, alanine and proline exhibited a positive correlation with salinity. Exposure to Aroclor 1254 did not have appreciable effects on total FAA levels, indicating that disruption of intracellular osmoregulation was not a major consequence of PCB toxicity. However, changes in individual amino acid concns in exposed shrimp were reflective of an altered metabolic state. Glycine, which did not show changes immediately following exposure, underwent large decreases after transfer to PCB-free water and indicated a delayed effect of PCB exposure. A correlation between salinity and the sum of glycine, alanine and proline did not exist in exposed shrimp.