Studies Concerning the Site of Renin Formation in the Kidney. II. Absence of Renin in Glomerular Kidney of Marine Fish.

The absence of renin in the aglomerular kidney of the midshipman, a marine fish, cannot now be construed as suggestive evidence of the probable formation of renin by the glomerular or arterial component of a kidney because the glomerular kidneys of other marine fish studied, also lack renin. The presence of renin in the glomerular kidneys of the catfish and carp, however, suggests that the kidney of most fresh water fish contains renin. Just why the kidney of marine fish, whether glomerular or aglomerular, should be devoid of detectable renin and the kidney of fresh water fish richly supplied with this same substance is a question which cannot be answered at this time. As has been noted, already, there is evidence that the tubular function in the kidneys of these two varieties of fish is probably not identical.