All Phenotypes Sirt1<tm3Fwa> MGI Mouse

decreased body weight ( J:155802 )

• reduced body weight beginning at 4-5 wk of age

• indistinguishable at birth and for their first month of life

decreased body length ( J:155802 )

• reduced snout-anus body length at 10 wk of age

• normal food consumption

decreased circulating glucose level ( J:155802 )

• slight reduction in fasting blood glucose levels in 10-week old mice

• reduced levels of blood glucose throughout the insulin tolerance test (ITT)

• similar performance in glucose tolerance tests, compared with wild-type littermate controls at 3 months of age

abnormal circulating hormone level ( J:155802 )

increased circulating prolactin level ( J:155802 )

• increased serum prolactin

decreased circulating insulin level ( J:155802 )

• trend toward a reduction in fasted insulin levels in 10-week old mice

• similar performance in insulin tolerance tests, compared with wild-type littermate controls at 3 months of age

decreased circulating insulin-like growth factor I level ( J:155802 )

• lower serum insulin-like growth factor I (IGF-1) levels in 10-wk-old mice than in wild-type littermate controls

• no change in serum IGF-1 levels, versus lowered serum IGF-1 levels in wild type after 10 wk of calorie restriction (CR)

decreased circulating growth hormone level ( J:155802 )

• nearly 50% lower serum growth hormone (GH) levels in 4-wk-old mice than in wild-type littermate controls

• normal serum concentrations of adrenocorticotropic hormone, thyroid-stimulating hormone, T3, and T4

impaired glucose tolerance ( J:155802 )

• old mice (10 months) display glucose intolerance

• produce more insulin in response to glucose injection than wild type at 10 months old

increased insulin sensitivity ( J:155802 )

• By ITT, high-fat-fed mice appear to remain somewhat more insulin-sensitive than wild-type mice fed the same diet

• CR induces only a modest improvement in insulin sensitivity

small pituitary gland ( J:155802 )

• smaller pituitaries than those of wild-type littermates

• no major defects upon histological examination

• normal density of GH positive cells

decreased pituitary gland weight ( J:155802 )

• reduced mass of the pituitaries normalized to body mass of 10-wk-old mice

abnormal pituitary gland physiology ( J:155802 )

• each pituitary gland contained significantly less stored GH

hyperactivity ( J:155802 )

• more active (on running wheels) than wild-type animals on an ad libitum diet

• no increase and slightly decreased physical activity, versus dramatically up-regulated activity in wild-type animals after 7 mo of CR