mortality/aging
• at weaning, homozygotes are present at a reduced Mendelian frequency (16% vs 25%)
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reproductive system
• at P29, female homozygotes show a poorly developed thin vaginal epithelial layer, little secretion, and a tightly closed vagina
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• female homozygotes display a pubertal delay that is, at least partially, due to a decrease in systemic estrogen levels
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• the average ages of vaginal opening time are at P26.1, P26.5, and P34.4 for wild-type, heterozygous, and homozygous females, respectively
• delayed vaginal opening can be rescued with estradiol treatment
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• female homozygotes have compromised reproductive function, with only 36% becoming pregnant after successful mating to wild-type males vs 75% of wild-type and heterozygous females
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• upon hormonal treatment, all wild-type females can be induced to superovulate with an average of 23.7 5.5 eggs per mouse; in contrast, only 60% of homozygotes ovulate with 10.4 3.8 eggs produced per mouse
• no mature follicles are observed in the ovaries of female mutants that fail to ovulate
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• female homozygotes exhibit significantly prolonged estrous cycles relative to wild-type females (14.6 2.7 days vs 8.1 2.4 days)
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• female homozygotes produce only 4.6 0.5 pups per litter vs 7.3 1.6 pups per litter produced by wild-type mothers
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growth/size/body
• adult male homozygotes show a 30% reduction in average body weight relative to wild-type males
• adult female homozygotes show a 15%-20% reduction in average body weight relative to wild-type females
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• ~10% of homozygotes display wasting syndrome, including weight loss, eye and skin infection, decreased mobility, arched back, and death at various ages
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• female homozygotes display a relatively normal growth until P9, followed by a significant decrease in growth rate at P9-P21, and severely pronounced retardation after P21
• male homozygotes display a relatively normal growth until P28, followed by a severe progressive growth retardation after P35
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endocrine/exocrine glands
• female homozygotes display delayed mammary gland ductal growth; estrogen therapy successfully rescues the growth deficiency of mammary ducts without changing IGF-1 levels
• female homozygotes show a dramatic decrease in mammary gland alveolar development in response to combined stimulation with 17beta -estradiol and progesterone
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• by 2 months, ductal branches penetrate only about 2/3 of the mutant mammary fat pad; ductal growth does not penetrate the entire fat pad until 11 weeks
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homeostasis/metabolism
• at P29 (i.e. before vaginal opening), female homozygotes exhibit only 60% of wild-type serum 17beta-estradiol levels
• although serum estradiol levels show a progressive increase at later stages, they remain significantly lower than wild-type levels
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• growth retardation is associated with a ~40% reduction in serum IGF-1 levels in both sexes; no statistical differences in GH levels are observed
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integument
• female homozygotes display delayed mammary gland ductal growth; estrogen therapy successfully rescues the growth deficiency of mammary ducts without changing IGF-1 levels
• female homozygotes show a dramatic decrease in mammary gland alveolar development in response to combined stimulation with 17beta -estradiol and progesterone
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• by 2 months, ductal branches penetrate only about 2/3 of the mutant mammary fat pad; ductal growth does not penetrate the entire fat pad until 11 weeks
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rough coat
(
J:62724
)
• homozygotes display a rough and dull hair coat
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cellular
• mouse embryonic fibroblasts exhibit decreased migration compared with wild-type cells
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