Specific insulin-like growth factor-I receptors on circulating bovine mononuclear cells.
We have examined the presence and properties of specific receptors for IGF-I on bovine mononuclear cells. Competitive binding studies showed that binding of [125I]IGF-I to mononuclear cells was inhibited by unlabelled peptides with the rank of IGF-I greater than IGF-II greater than insulin. The binding of [125I]IGF-I was a function of the cell concentration. Equilibrium dissociation constant and receptor concentration values for the average of 9 adult cows were 1.13 +/- 0.11 nM and 108.9 +/- 24.1 fMol/10(7) cells, respectively. Moreover, IGF-I stimulated thymidine incorporation into bovine mononuclear cells in the absence of serum and phytohemagglutinin (PHA). The existence of specific and functional IGF-I receptors on circulating bovine mononuclear cells would provide an easily accessible source for studying IGF-I receptor changes in the bovine, both in physiologic and pathologic states.
Zhao
X
X
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
McBride
B W
BW
Trouten-Radford
L M
LM
Burton
J H
JH
D000818:Animals; D002417:Cattle; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000032:analysis*; D017451:Receptors, Somatomedin
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I