A comparison of osmolality and the concentrations of major osmolytes and water in seawater, food (deheaded hake, Merluccius productus), blood plasma and the fluid of stomach-1 (cardiac stomach) prior to feeding (120 h fasting) in the dogfish shark
| . | Seawater (N=4) . | Food†(N=5) . | Blood plasma (N=8) . | Stomach-1 fluid (N=8) . |
|---|---|---|---|---|
| Osmolality (mosmol kg-1) | 967±3 (a) | 400‡ | 973±6 (b) | 949±25 (a) |
| Ion concentrations (mmol l-1) | ||||
| Na+ | 452±3 (a) | 55.6±2.6 (b) | 254±3 (c) | 400±9 (d) |
| Cl- | 515±3 (a) | 46.4±2.4 (b) | 249±2 (c) | 440±14 (d) |
| K+ | 9.8±0.5 (a) | 112.9±2.3 (b) | 3.5±0.9 (c) | 11.6±0.6 (a) |
| Ca2+ | 9.5±0.1 (a) | 73.0±3.2 (b) | 4.3±0.1 (c) | 8.7±0.4 (a) |
| Mg2+ | 52.0±0.4 (a) | 15.9±0.2 (b) | 1.4±0.1 (c) | 35.3±1.2 (d) |
| Urea | 0.0±0.0 (a) | 4.2±1.0 (b) | 438±22 (c) | 145±15 (d) |
| Water (%) | (96.8)* | 80.18±0.23 (a) | 96.15±0.39 (b) | 97.25±0.49 (b) |
| . | Seawater (N=4) . | Food†(N=5) . | Blood plasma (N=8) . | Stomach-1 fluid (N=8) . |
|---|---|---|---|---|
| Osmolality (mosmol kg-1) | 967±3 (a) | 400‡ | 973±6 (b) | 949±25 (a) |
| Ion concentrations (mmol l-1) | ||||
| Na+ | 452±3 (a) | 55.6±2.6 (b) | 254±3 (c) | 400±9 (d) |
| Cl- | 515±3 (a) | 46.4±2.4 (b) | 249±2 (c) | 440±14 (d) |
| K+ | 9.8±0.5 (a) | 112.9±2.3 (b) | 3.5±0.9 (c) | 11.6±0.6 (a) |
| Ca2+ | 9.5±0.1 (a) | 73.0±3.2 (b) | 4.3±0.1 (c) | 8.7±0.4 (a) |
| Mg2+ | 52.0±0.4 (a) | 15.9±0.2 (b) | 1.4±0.1 (c) | 35.3±1.2 (d) |
| Urea | 0.0±0.0 (a) | 4.2±1.0 (b) | 438±22 (c) | 145±15 (d) |
| Water (%) | (96.8)* | 80.18±0.23 (a) | 96.15±0.39 (b) | 97.25±0.49 (b) |