Influence of divalent cations on the detection of somatogenic and lactogenic binding sites in mouse liver cells.
Specific binding of 125I-labelled human somatotropin was demonstrated in isolated hepatocytes from male mice. In the presence of divalent cations (Ca2+ and Mg2+) the binding of 125I-labelled human somatotropin was competitive with ovine prolactin. Scatchard analysis of competition data indicated a KD of 1.4 +/- 0.2 nM and a binding capacity of 13 000 +/- 2000 sites/cell. In the absence of divalent cations and in the presence of EDTA, human and bovine somatotropins were found to be equally effective to displace bound 125I-labelled human somatotropin, while ovine prolactin showed a weak competition. In this case, the binding capacity was 8400 +/- 1500 sites/cell and the KD was 1.1 +/- 0.1 nM.
Ciccia-Torres
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GN
Dellacha
J M
JM
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002413:Cations, Divalent / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011981:Receptors, Prolactin; D011986:Receptors, Somatotropin
D002413:Cations, Divalent; D011956:Receptors, Cell Surface; D011981:Receptors, Prolactin; D011986:Receptors, Somatotropin; D013006:Growth Hormone; D004492:Edetic Acid