Title

Glucose Kinetics in Neonatal Elephant Seals During Postweaning Aphagia

Document Type

Article

Publication Date

4-1989

Publication Title

Marine Mammal Science

Keywords

Northern elephant seal, Glucose metabolism, Fasting

ISSN

0824-0469

Volume

5

Issue/No.

2

First Page

99

Last Page

115

Abstract

Northern elephant seal (Mirounga angustirostris) pups undergo extended periods of terrestrial aphagia after weaning and exhibit a paradoxical fasting hyperglycemia. To investigate the details of glucose metabolism during this period, reversible and irreversible radiotracers were used to determine the body mass of glucose, and rates of glucose turnover, recycling, and oxidation in fasting seal pups. A typical 75 kg pup has a glucose mass of about 4.5 g (60 mg/kg), and a blood glucose concentration of about 174 mg/dl. Blood glucose removal rate was about 30 grams per day (17 mg/kg · h-1), but less than 2.5% of this glucose was oxidized, contributing less than 1% of the total metabolic rate. About 20% of the glucose pool was removed from the blood per hour, yielding a turnover time in the vascular space of about five hours. Most glucose removed from the blood was returned to the blood by recycling. Such recycling may contribute to mechanisms which prolong survival during fasting, such as high rates of triacyclglycerol turnover, synthesis of new protein pools, low ketone levels, and the Cori cycle which is important during diving.

Comments

@1989 by the Society for Marine Mammalogy

Additional Comments

NIH-MBRS/DRR grant #: RR08132

DOI

10.1111/j.1748-7692.1989.tb00326.x

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Peer Reviewed

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