Transferrin receptor activity in rat mammary epithelial cells
Grigor, M.R.; Wilde, C.J.; Flint, D.J.
Biochemistry International 17(4): 747-754
1988
ISSN/ISBN: 0158-5231 PMID: 3240322 Document Number: 314081
The binding of 125I-transferrin to rat mammary cells isolated by collagenase and hyaluronidase digestion has been investigated. Surface binding was determined at 4 degrees C and total binding also at 4 degrees C but in the presence of 0.1% w/v saponin. KD values between 20 and 25 nM were obtained. Binding assays at 37 degrees C showed the internalisation of the receptor and the bound transferrin was occurring but also provided evidence for an impaired recycling of the receptors to the cell surface in the freshly isolated cells. No differences in total binding were observed in cells prepared at different stages of lactation with a mean value of 29 fmol transferrin bound/micrograms cellular DNA, equivalent to 180,000 receptors per cell.