ISSN:
1432-136X
Schlagwort(e):
Glomerular filtration rate
;
Fasting
;
Water conservation
;
Protein catabolism
;
Elephant seal, Mirounga
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Medizin
Notizen:
Abstract Urine production and N output were monitored in northern elephant seal (Mirounga angustirostris) pups progressing through 10 weeks of a natural postweaning fast. Urine output declind by 84% (to 69±12 ml·day−1) at 10 weeks (P〈0.05). Glomerular filtration rate at 10 weeks was 51% of the 67±3 ml serum·min−1 observed during week 1 (P〈0.05). Urine N excretion fell by 69% to 1.2±0.17 g·day−1, while urinary concentration increased (P〈0.05). Serum urea declined from an initial 11 mmol·1−1 to 5–7 mmol·1−1 by 5 weeks. The fall in urinary N loss (and thus amino acid oxidation) was concomitant with depressed metabolic rate. Therefore, protein contributed little toward meeting energy demands (i.e., 〈4% of average metabolic rate) throughout fasting. These data indicate that fasting pups improve water conservation and minimize protein catabolism during prolonged natural fasts without an exogenous source of water.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00265640
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