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Lipid synthesis and distribution during the annual cycle of a hibernator
Author(s) -
Otis Jessica P,
Sahoo Daisy,
Drover Victor A,
Eric Yen C. L.,
Carey Hannah V
Publication year - 2010
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.24.1_supplement.1055.5
Subject(s) - medicine , chemistry , endocrinology , apolipoprotein b , hibernation (computing) , lipid metabolism , triglyceride , metabolism , white adipose tissue , adipose tissue , biochemistry , biology , cholesterol , state (computer science) , algorithm , computer science
Although the seasonal shift from carbohydrate to lipid metabolism in hibernators is well established, a comprehensive study of lipid regulation in one species is lacking. To address this we studied triglyceride (TG) and lipoprotein metabolism in spring (SPR), summer (SUM) and hibernating (HIB) 13‐lined ground squirrels (5–6 per group). Plasma TGs are carried in VLDL particles in all seasons. There are no differences among the groups in ApoB mRNA in liver and gut or ApoB protein in liver and plasma. Fasting decreases plasma TGs 2‐fold in SPR (p<0.05), but not in SUM. Plasma TGs are lower in torpid HIB (76.7±43.9 mg/dl) than interbout arousal (IBA) HIB (178.0±17.4 mg/dl), and both are less than SUM (278.2±44.4 mg/dl) (P<0.05). Plasma free fatty acids (FFAs) are highest in torpid HIB, equal in SUM and IBA HIB (P<0.001), and are not affected by fasting in SPR or SUM. Liver TGs are higher in torpid HIB than in SPR or IBA HIB (P<0.05), but liver FFAs are highest in torpid HIB (P<0.05). White adipose tissue (WAT) TGs do not vary among states, but WAT FFAs are lower in torpid HIB than SUM (P<0.05). mRNA levels of the TG synthesis enzymes MGAT2 and DGAT2 are greater in HIB than SUM (P<0.05). The results provide insight into how hibernating species regulate synthesis and distribution of lipids throughout the body during their annual cycle of feeding and fasting.