Fatty acid metabolism in fasting elephant seal pups.
The turnover of two plasma free fatty acids (FFA) were measured in 5 northern elephant seal pups (Mirounga angustirostris) after approximately 2 months of post-weaning fasting. Turnover was determined using simultaneous bolus injections of 14C-palmitate, 3H-oleate and Evans blue (EB) administered via an indwelling extradural intravertebral catheter. At this time in their natural fast, the seals exhibited plasma FFA levels and turnover values higher than reported for other marine mammals and most terrestrial carnivores. There was no consistent difference between plasma FFA turnover measured by palmitate or oleate tracers. The results imply that FFA metabolism is the primary source of energy during fasting. This is interesting in light of previous observations of minimal ketoacid accumulation and low levels of glucose and protein energy production during fasting in these juvenile seals.
Castellini
M A
MA
Zoology Department, University of British Columbia, Vancouver, Canada.
Costa
D P
DP
Huntley
A C
AC
D000818:Animals; D001481:Basal Metabolism; D010872:Caniformia / Q000097:blood*; D002250:Carbon Radioisotopes; D004734:Energy Metabolism; D005070:Evans Blue; D005215:Fasting; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D007700:Kinetics; D019301:Oleic Acid; D009829:Oleic Acids / Q000097:blood; D010101:Oxygen Consumption; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000097:blood; D046048:Seals, Earless / Q000097:blood*; D014316:Tritium
D002250:Carbon Radioisotopes; D005230:Fatty Acids, Nonesterified; D009829:Oleic Acids; D010169:Palmitic Acids; D014316:Tritium; D019301:Oleic Acid; D019308:Palmitic Acid; D005070:Evans Blue