Is the milk-fat-globule membrane a model for mammary secretory cell apical membrane?
K+(Rb+) uptake by milk-fat-globule membrane (MFGM) vesicles and skim-milk membrane vesicles isolated from bovine milk has been studied. The K+(Rb+) permeability of MFGMs was very low in both high- and low-strength ionic media. In contrast, skim-milk membranes displayed a significant permeability to K+(Rb+). The results suggest that these membrane preparations do not originate from the same source on the mammary secretory cell and also call into question the suitability of the MFGM as a model for the apical membrane of mammary epithelial cells.
Shennan
D B
DB
Hannah Research Institute, Ayr.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005223:Fats; D006801:Humans; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism*; D008892:Milk; D008954:Models, Biological; D010539:Permeability; D011188:Potassium / Q000493:pharmacokinetics; D014634:Valinomycin / Q000494:pharmacology
D005223:Fats; D014634:Valinomycin; D011188:Potassium