Chemical composition of the body fluids andmuscle of the hagfish Myxine glutinosa and the rabbit-fish Chimaera monstrosa

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Abstract

Comprehensive analyses have been made of the plasma and parietal muscle of the marine cyclostome Myxine glutinosa and of the chimaeraoid Chimaera monstrosa, and the sum of some 17 constituents compared with the directly determined osmotic concentration of plasma. Both Myxine and Chimaera plasmas are isosmotic with sea water within 2%. Ions account for at least 96% of the total concentration of the plasma in Myxine and about 60% in Chimaera, but the blood of the latter contains 332 mM urea, compared with 3 mM in Myxine. In muscle a similar divergence exists, the urea concentrations per kilogram muscle water being practically the same as in the respective plasmas of the two species. The mean values in millimoles of the other nitrogenous constituents of muscle are for Myxine and Chimaera (figures for latter in brackets), trimethylamine oxide 87 (189), betaine 65 (38), creatine and creatinine 30 (37), amino acids 291 (43). Using osmotic coefficients the calculated osmotic concentration of muscle exceeds that of plasma in Myxine and possible reasons for this are discussed.

Estimates of inulin space in Myxine muscle have enabled intracellular concentrations of ions to be calculated. Analysis of Myxine bile shows it to have much higher concentrations of sodium, calcium and magnesium, and much lower chloride, than plasma. The resulting large anion deficit is presumably made up chiefly by the bile salt myxinol disulphate.

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