THE EXCRETION OF INULIN AND GLUCOSE BY THE CRAYFISH ANTENNAL GLAND

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Abstract
This study was undertaken in an attempt to resolve the problem of how the crayfish antennal gland (kidney) forms the primary urine. Evidence presented in the literature supports both filtration and secretion hypotheses. Inulin was excreted by the green gland of the crayfishes studied. Glucose normally did not appear in the urine of the crayfishes. However, when the blood level of that substance was raised to about 200 mg%, and when the crayfishes were handled for periods longer than 30 hr., glucose often appeared in the urine. Injected phlorizin caused glucosuria. Since inulin (and glucose during phlorizin poisoning) urine/blood ratios usually were greater than 1, there was evidence that, additional to the already established marked solute reabsorption, there is considerable water reabsorption from the urine by the crayfish antennal gland. The authors conclude that the crayfish kidney functions in a manner analogous (at least superficially) to that of the vertebrate glomerular kidney.