title: Beyond thermoregulation: metabolic function of cetacean blubber in migrating bowhead and beluga whales.
abstract: The processes of lipid deposition and utilization, via the gene leptin (Lep), are poorly understood in taxa with varying degrees of adipose storage. This study examines how these systems may have adapted in marine aquatic environments inhabited by cetaceans. Bowhead (Balaena mysticetus) and beluga whales (Delphinapterus leucas) are ideal study animals-they possess large subcutaneous adipose stores (blubber) and undergo bi-annual migrations concurrent with variations in food availability. To answer long-standing questions regarding how (or if) energy and lipid utilization adapted to aquatic stressors, we quantified variations in gene transcripts critical to lipid metabolism related to season, age, and blubber depth. We predicted leptin tertiary structure conservation and assessed inter-specific variations in Lep transcript numbers between bowheads and other mammals. Our study is the first to identify seasonal and age-related variations in Lep and lipolysis in these cetaceans. While Lep transcripts and protein oscillate with season in adult bowheads reminiscent of hibernating mammals, transcript levels reach up to 10 times higher in bowheads than any other mammal. Data from immature bowheads are consistent with the hypothesis that short baleen inhibits efficient feeding. Lipolysis transcripts also indicate young Fall bowheads and those sampled during Spring months limit energy utilization. These novel data from rarely examined species expand the existing knowledge and offer unique insight into how the regulation of Lep and lipolysis has adapted to permit seasonal deposition and maintain vital blubber stores.
authors: Department of Biology, The University of Akron, 305 Buchtel Ave, Akron, OH, 44325, USA. hcball08@gmail.com.|Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA. hcball08@gmail.com.
authors: H C
authors: HC
authors: Ball
authors: Department of Biology, The University of Akron, 305 Buchtel Ave, Akron, OH, 44325, USA.
authors: R L
authors: RL
authors: Londraville
authors: Department of Biology, The University of Akron, 305 Buchtel Ave, Akron, OH, 44325, USA.|Hudson Alpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL, 35806, USA.
authors: J W
authors: JW
authors: Prokop
authors: North Slope Borough Department of Wildlife Management, P.O. Box 69, Barrow, AK, 99723, USA.
authors: John C
authors: JC
authors: George
authors: North Slope Borough Department of Wildlife Management, P.O. Box 69, Barrow, AK, 99723, USA.
authors: R S
authors: RS
authors: Suydam
authors: Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA.
authors: C
authors: C
authors: Vinyard
authors: Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH, 44272, USA.
authors: J G M
authors: JG
authors: Thewissen
authors: Department of Biology, The University of Akron, 305 Buchtel Ave, Akron, OH, 44325, USA.
authors: R J
authors: RJ
authors: Duff
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000375:Aging / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D050643:Beluga Whale / Q000502:physiology*; D001833:Body Temperature Regulation; D050642:Bowhead Whale / Q000502:physiology*; D005260:Female; D006801:Humans; D020738:Leptin / Q000235:genetics / Q000378:metabolism; D008049:Lipase / Q000235:genetics; D050356:Lipid Metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D020318:Rats, Long-Evans; D054411:Receptors, Leptin / Q000235:genetics; D012621:Seasons
chemical_list: D020738:Leptin; D054411:Receptors, Leptin; D008049:Lipase
keywords: Blubber; Bowhead whale; Development; Leptin; Metabolic activity