Biochemical Profiles Of The Hemolymph Of The Horseshoe Crab, Limulus polyphemus     Stephen A. Smith1, James M. Berkson2, and Tanya L. Tag1   1Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442 USA; 2Department of Fisheries and Wildlife, Virginia Polytechnic Institute and State University, Blacksburg, VA   24061-0321 USA         The horseshoe crab (Limulus polyphemus) is one of four extant species remaining worldwide, and can be found along the western Atlantic coast from Maine to the Gulf of Mexico. While the unusual characteristics of the crab’s “blue blood” and the composition of the LAL have been studied in detail, basic biochemical parameters of the hemolymph of the horseshoe crab are lacking.  Thus, hemolymph from fifty adult (29 male and 21 female) horseshoe crabs was collected for analysis. Hemolymph samples were analyzed using an automated dry chemistry system (Kodak Ektachem 700, Eastman Kodak Co., Rochester, NY, USA). Copper levels in the hemolymph were determined by atomic absorption using a spectrophotometer (Beckman Du 680 B, Fullerton, CA, USA) set at 580Å, while hemolymph osmolality was determined using a freezing point depression osmometer (Advanced Micro-osmometer, Model 3 MoPlus, Advanced Instruments, Inc, Norwood, MA, USA). Results of the biochemistry parameters (mean values) for the hemolymph of the horseshoe crab were: total protein (8.15 g/dl), glucose (58.5 mg/dl), creatinine (0.7 mg/dl), cholesterol (0.8 mg/dl), sodium (389.5 mEq/l), potassium (12.5 mEq/l), chloride (445.1 mEq/l), calcium (39.0 mg/dl), magnesium (96.1 mg/dl), phosphorus (3.4 mg/dl), triglycerides (5.3 mg/dl), amylase (9.3 U/l)), lipase (32.7 U/l), alkaline phophatase (12.1 U/l), aspartate aminotransferase (5.4 U/l) and gamma glutamyl transferase (0.92 U/l).