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Molecular characterization of nonshivering thermogenesis in a ‘protoendothermic’ mammal, the Lesser‐hedgehog tenrec (Echinops telfairi)
Author(s) -
Ölkrug Rebecca,
Götze Nadja,
Heldmaier Gerhard,
Jastroch Martin,
Meyer Carola Waltraud
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.886.2
Subject(s) - thermogenesis , biology , brown adipose tissue , thermogenin , adipose tissue , medicine , anatomy , endocrinology
The molecular events and mechanisms that facilitated the evolutionary transition from ecto‐to endothermia in vertebrates are still unknown but must have involved the development of endogenous heat production. The Lesser‐hedgehog tenrec, Echinops telfairi, is considered ‘protoendothermic’ as a result of ectothermic‐like body temperature patterns. We studied metabolic responses of E. telfairi in vivo and observed daily cycles of hypothermia ranging from 21° to 33°C body temperature (Ta: 20°C). Rewarming rates from torpor were independent of β3‐adrenergic stimulation (judged with inhibitor SR59230A), emphasizing that classical adaptation of thermogenesis as found in brown adipose tissue (BAT) of rodents was absent. However, we found brown adipose‐like tissue predominantly located in the abdominal cavity. Molecular analysis confirmed the expression of UCP1 mRNA and protein. The proton leak of isolated mitochondria could be inhibited more than 50% by GDP, suggesting UCP1‐dependent proton conductance. Taken together, BAT in E. telfairi appears to be consistent with the thermogenic function as found in rodents, but does not display the typical thermogenic adaptation. We are currently comparing UCP1 specific activity of E. telfairi with mouse (Mus musculus) in HEK293 cells to explore whether differences in physiological heat production are reflected on the molecular evolution of UCP1.