Comparison of the roles of insulin and insulin-like growth factor I in casein gene expression and in the development of alpha-lactalbumin and glucose transport activities in the mouse mammary epithelial cell.
The concentration-activity profiles for insulin and insulin-like growth factor I (IGF-I; in the presence of and insulin-like growth factor I (IGF-I; in the presence of hydrocortisone and PRL) have been compared in terms of the accumulation of beta-casein mRNA, total casein synthesis, and alpha-lactalbumin and basal carrier-mediated glucose transport activities in mammary epithelial cells from midpregnant mice. For the accumulation of the casein mRNA and the induction of casein synthesis and alpha-lactalbumin activity, the insulin ED50 is 1-2 ng/ml, while that for IGF-I is 10- to 20-fold greater. The effects of insulin and IGF-I are not additive in these instances. For the induction of basal carrier-mediated glucose transport, the insulin ED50 is 8 ng/ml, and that for IGF-I is 16 ng/ml. Either factor can induce transport activity up to the level present in the cells from 2-day lactating mice. In this instance the effects are additive; insulin and IGF-I together can induce the transport up to the 10-day lactating level.
D019325:3-O-Methylglucose; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002364:Caseins / Q000096:biosynthesis* / Q000235:genetics; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007768:Lactalbumin / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism; D051379:Mice; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D013002:Somatomedins / Q000494:pharmacology*
D002364:Caseins; D007328:Insulin; D008757:Methylglucosides; D012333:RNA, Messenger; D013002:Somatomedins; D019325:3-O-Methylglucose; D007334:Insulin-Like Growth Factor I; D007768:Lactalbumin; D005947:Glucose