Filtration rate and water diuresis in the seal, Phoca vitulina

✍ Scribed by Ladd, Michael ;Raisz, Lawrence G. ;Crowder, Charles H. ;Page, Lot B.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1951
• Tongue: English
• Weight: 395 KB
• Volume: 38
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030380203

✦ Synopsis

The theory that water reabsorption in the renal tubules is partitioned between an obligatory (proximal) and a facultative (distal) process (Smith, '51) is based in part on the fact that of the total water contained in the glomerular filtrate only a limited fraction (on the average about 15%) is available for excretion during water diiiresis. Ludemann, Raisz, and Wirz (personal communication) have shown in the dog that this fraction varies within the range of 11 to 19% when the filtration rate is raised or lowered by changing the protein content of the diet. I n the marine seal, Phocn uitulina, the filtration rate may be increased markedly by feeding (Hiatt and Hiatt, '42) and greatly reduced by excitation of the diving reflex (Bradley and Bing, '42). This animal therefore affords an excellent opportunity to examine the influence of wide changes in filtration rate on facultative water excretion.

Methods

The animals used in this study consisted of 15 female and 5 male young seals captured shortly after weaning and weighing 16 to 26 kg, and one 1-year-old female weighing 31 kg.3