Constituents in Skipjack Muscle and Blood — Sather and Rogers 
405 
Model B spectrophotometer. The Geyer and 
Bowie (1961) method was employed to deter- 
mine the calcium content of the muscles. Both 
the plasma and muscle magnesium were esti- 
mated by the flame spectrophotometric method 
of Van Fossan et al. (1959). An organic dilut- 
ing solution was substituted for acetone. The 
composition of the former was 500 ml iso- 
propanol, 74.6 mg KC1, 292 mg NaCl, and 
300 ml deionized water. The muscle calcium 
and magnesium and the plasma magnesium 
samples were determined on a Beckman Model 
DU spectrophotometer equipped with a hydro- 
gen-oxygen burner and a photomultiplier. The 
muscle and plasma chloride contents were deter- 
mined using a Buchler-Cotlove chloridometer. 
To ascertain whether there was a difference 
in the electrolyte composition of the red and 
white muscles, the data were statistically ana- 
lyzed employing the standard t-test for group 
comparisons. 
To compare the muscle results with those 
of other investigators, the inulin space of the 
two muscle types was determined using C 14 - 
inulin. The tissues (about 50 mg) were incu- 
bated in vitro at 20 °C in tuna physiological 
saline containing 2900 cpm/ml of inulin. The 
composition of the saline was 19.99 mEq 
NaCl /liter, 7.52 mEq KCl/liter, 3.54 mEq 
CaCl 2 /liter, 2.70 mEq MgS0 4 /liter, 20 ml of 
phosphate buffer (pH = 7.4), and 4% glu- 
cose. At -J, 1, 2, and 3 hours triplicate samples 
were removed from the media. After digestion 
in warm 30% KOH, 0.5-ml aliquots were 
transferred to pyrex planchettes and radio- 
assayed on a Nuclear- Chicago Model 181 
Scaler fitted with a DS-3 gas flow detector. All 
samples were corrected for self-absorption. 
RESULTS 
The data for the whole blood and plasma 
are contained in Table 1. The concentrations 
of the electrolytes and the osmolality are ex- 
pressed in mEq/liter and mOs/liter, respec- 
tively. The bottom values under each column 
are the means ± the standard error of the 
means (S.E.). 
The mean values for the blood components 
were as follows: hematocrit = 52.61%, pH — 
7.32, osmolality = 414.56, sodium = 203.74, 
potassium — 6.81, chloride = 177.43, cal- 
cium = 7.56, and magnesium = 2.22. 
The electrolyte data for the red and white 
TABLE 1 
Blood Composition of K. pelamis 
TUNA 
HEMAT. 
pH 
OSM. 1 
Na 2 
K 2 
C12 
Ca 2 
Mg 2 
1 
56.0 
7.50 
450 
200.3 
4.70 
178.00 
7.81 
3.35 
2 
54.0 
7.18 
416 
196.2 
6.78 
189.67 
7.92 
2.27 
3 
45.0 
7.38 
400 
194.9 
5.71 
186.67 
6.54 
1.66 
4 
48.0 
7.30 
396 
185.5 
6.56 
176.00 
7.14 
1.30 
5 
51.0 
7.29 
394 
186.2 
9.64 
171.00 
7.46 
1.80 
6 * 
58.0 
7.25 
428 
— 
— 
162.00 
10.55 
2.68 
7 * 
52.0 
7.38 
445 
231.8 
2.81 
189 00 
7.08 
4.05 
8 
48.0 
7.41 
400 
200.0 
7.50 
176.00 
7.04 
1.55 
9 
39-0 
7.33 
401 
200.5 
5.97 
176.00 
6.28 
1.53 
10 * 
59.0 
7.41 
436 
222.7 
3.85 
182.00 
9.41 
3.18 
11 * 
59-0 
7.42 
425 
213.6 
8.85 
181.00 
7.64 
2.32 
12 * 
55.0 
7.22 
426 
211.4 
8.71 
177.00 
8.37 
2.70 
13 
52.0 
7.31 
406 
200.0 
11.60 
176.50 
6.51 
1.45 
14 
53.0 
7.22 
416 
202.5 
8.10 
175.00 
7.43 
2.35 
15 
51.0 
7.18 
414 
209.5 
3.80 
174.50 
7.46 
1.72 
16 
46.0 
— 
397 
201.0 
7.60 
173.00 
6.19 
1.59 
17 * 
57.0 
— 
398 
— 
— 
173.00 
7.22 
2.00 
18 
64.0 
— 
414 
— 
— 
— 
8.13 
2.41 
Mean 
52.61 
7.32 
414.56 
203.74 
6.81 
177.43 
7.56 
2.22 
S . E . 
1.417 
0.025 
4.082 
3.216 
0.624 
1.652 
0.256 
0.177 
* Hemolyzed blood. 
1 Osmolality values in mOs/liter. 
2 Electrolyte values in mEq/liter. 
