Glucose and ketone body turnover in fasting grey seal pups.
Concentration and metabolic replacement (turnover) rate of glucose and ketone bodies were determined at intervals during a 52 day postweaning fast in five grey seal (Halichoerus grypus) pups, using bolus injections of radiotracers. Blood glucose was maintained at a high level throughout the fast, while beta-hydroxybutyrate increased 26 times from day 3 to day 37, whereafter it by and large was maintained. Glucose replacement rate decreased to 56% of the day 9 value at day 37 and dropped further to only 32% of the day 9 level at day 52 in two seals, while in another 2 seals it increased at this late stage. The average ketone body replacement rate ranged between 8.6 and 13.8 mumols min-1 kg-1, but did not change significantly (P greater than 0.05) during the fasting period. These results suggest a reduced gluconeogenesis from protein and increased production of ketone bodies, which may in part replace glucose as energy source during fasting.
Nordøy
E S
ES
Department of Arctic Biology, University of Tromsø, Norway.
Blix
A S
AS
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D005215:Fasting / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006029:Glycosuria / Q000378:metabolism; D006885:Hydroxybutyrates / Q000097:blood; D007657:Ketone Bodies / Q000378:metabolism*; D008297:Male; D046048:Seals, Earless / Q000378:metabolism*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D007657:Ketone Bodies; D005947:Glucose