@entity7105 seals fast for prolonged periods without access to water. This is made possible, in part, by reductions in urine production. However, the mechanisms involved in reducing urine production are not understood. In this study, glomerular filtration rate (GFR) was measured in five northern @entity7105 seal pups (Mirounga angustirostris) via the inulin clearance technique. Measurements were made during day 9 and day 18-22 of nursing and the second and eighth week of the postweaning fast. Plasma @entity1369 and @entity701 concentrations, quantified by radioimmunoassay, were measured in eight other weanlings during the second and eighth week of the fast. Mean GFR was 79.3+/-29.3 ml/min during the early suckling period and 78.2+/-17.1, 89.8+/-52.7, and 80.4+/-12.2 ml/min during the late suckling, early fasting and late fasting periods, respectively. Differences between nursing and fasting were insignificant, possibly because reduced protein oxidation during suckling and rapid recruitment of protein for tissue synthesis obviated the need for postprandial hyperfiltration. Alternatively, maintenance of GFR during fasting may facilitate @entity1133 concentration by compensating for reductions in the fractional excretion of @entity1133 . It is further hypothesized that @entity1369 is primarily responsible for mediating renal water reabsorption in this system.

Renal function in suckling and fasting pups of the northern XXXX seal.

@entity7105 :: ('9783', 'Species') :: ['Elephant', 'elephant'] @entity1369 :: ('MESH:D000450', 'Chemical') :: ['aldosterone'] @entity701 :: ('MESH:D006854', 'Chemical') :: ['cortisol'] @entity1133 :: ('MESH:D014508', 'Chemical') :: ['urea']
@entity7105 :: (9783,Species) :: ['elephant']
