Analysis Tools
adipose tissue
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• older mice accumulated less lipid in brown fat
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• white adipocytes are smaller
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• less white adipose tissue regardless of diet up to 9 months
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homeostasis/metabolism
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• no difference in body weight up to 9 months of age regardless of diet
• tended not to become obese on high fat diets
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• maintained a higher core body temp (by 0.6C) when cold exposed
• oxygen consumption about 10% higher when cold exposed than wild-type
• higher rate of lipid catabolism after overnight cold exposure; brown fat lipid volume dropped from 23% to under 2%
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• after water immersion, males exhibit a lower body temperature (28.4 C versus 30 C) and a slower recovery to normal body temperature (40 min versus ~25 min) relative to wild-types males, indicating impaired thermoregulation
• females also show lower body temperature after immersion in water and a slower recovery
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• kept plasma glucose levels significantly lower than normal
• more efficiently eliminated blood glucose after an exogenous load
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• slightly lower respiratory exchange rate indicating a higher percentage of lipid metabolism
• adiposity index 3.47% as opposed to 9.05% for wild-type
• 60% lower lipid content of the body
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• 60% decrease
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• fasting levels in plasma of nonesterified fatty acids (NEFA) 60% lower
• plasma glycerol levels normal regardless of diet
• less NEFA released from brown fat explants in spite of 67% increase in glycerol release
• no differences in white adipose tissue
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• lipolysis enhanced
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integument
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• sebocytes accumulate a larger number of smaller-size lipid droplets than those of wild-type controls, indicating reduced lipid storage in the sebaceous glands
• the diameter of the largest LD is 0.86 um versus 2.1um in wild-type sebocytes
• however, gross sebaceous gland differentiation appears normal
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• meibocytes accumulate a larger number of smaller-size lipid droplets than those of wild-type controls, indicating reduced lipid storage in the Meibomian glands
• however, gross morphology of Meibomian glands is normal, as shown by H&E staining
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• mice exhibit significantly reduced levels of skin surface lipids (esp. triacylglycerides, diacylglycerides, and wax diesters) relative to wild-type controls
• at 3 and 10 months of age, males show a 83% reduction of triacylglyceride (TAG) levels relative to wild-type controls
• at 3 months of age, males show a 30% reduction of wax diesters (WDE, a major wax ester in mouse sebum), with a further reduction (61%) noted at 10 months
• a reduction of levels of skin TAGs and WDEs is also observed in females
• however, levels of skin free fatty acids, cholesterol esters, and free cholesterol are similar to those in wild-type controls
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• at 10 months of age or later, hair appears lighter, drier, and less dense in both sexes relative to that of wild-type controls
• scratch marks on the chin at 10 months of age or later
• dry hair and hair loss are not the result of the lean phenotype
• when hairs of 7-week-old mice are unplugged in the telogen phase of the hair cycle to induce the next anagen, no differences in skin color or hair growth are observed relative to wild-type controls
• no morphological differences can be seen in the hair roots or hair shafts relative to wild-type controls
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• mice exhibit a lighter hair color at 10 months of age
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• at 10 months of age, 53% of males and 27% of females show focal hair loss
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• patches of hair loss on the neck area at 10 months of age or later
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skin lesions
(
J:215366
)
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• skin lesions at 10 months of age or later
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pigmentation
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• mice exhibit a lighter hair color at 10 months of age
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vision/eye
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• meibocytes accumulate a larger number of smaller-size lipid droplets than those of wild-type controls, indicating reduced lipid storage in the Meibomian glands
• however, gross morphology of Meibomian glands is normal, as shown by H&E staining
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endocrine/exocrine glands
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• sebocytes accumulate a larger number of smaller-size lipid droplets than those of wild-type controls, indicating reduced lipid storage in the sebaceous glands
• the diameter of the largest LD is 0.86 um versus 2.1um in wild-type sebocytes
• however, gross sebaceous gland differentiation appears normal
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• meibocytes accumulate a larger number of smaller-size lipid droplets than those of wild-type controls, indicating reduced lipid storage in the Meibomian glands
• however, gross morphology of Meibomian glands is normal, as shown by H&E staining
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• mice exhibit significantly reduced levels of skin surface lipids (esp. triacylglycerides, diacylglycerides, and wax diesters) relative to wild-type controls
• at 3 and 10 months of age, males show a 83% reduction of triacylglyceride (TAG) levels relative to wild-type controls
• at 3 months of age, males show a 30% reduction of wax diesters (WDE, a major wax ester in mouse sebum), with a further reduction (61%) noted at 10 months
• a reduction of levels of skin TAGs and WDEs is also observed in females
• however, levels of skin free fatty acids, cholesterol esters, and free cholesterol are similar to those in wild-type controls
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growth/size/body
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• in a water repulsion experiment, males remain wet 25 min after water immersion, unlike wild-type controls which are nearly dry
• males absorb 8% of water relative to their body weight versus only 4% in wild-type controls, indicating a 2-fold increase in water retention
• females also exhibit lower water repulsion relative to wild-type controls
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