Distribution of receptors for insulin and insulin-like growth factor I (somatomedin C) in the adrenal gland.
Rat adrenal glands contain cell surface high-affinity receptors for several peptide hormones. Receptors for IGF-I were abundant in this tissue, but receptors for insulin were relatively scarce. The behavior of adrenal membrane IGF-I receptors in radioligand binding assays was similar to the behavior of IGF-I receptors from other tissues, with a KD congruent to 6.2 x 10(-9) M. Covalent cross-linking studies with [125I]IGF-I revealed an IGF-I receptor alpha-subunit with Mr congruent to 135,000 on dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions, as well as a smaller radiolabeled peptide, Mr = 116,000. In contrast, little binding of [125I]insulin to adrenal membranes was observed and no labeling occurred in cross-linking studies using [125I]insulin. These results contrast with the findings of whole-body autoradiographic studies that indicated substantial binding of [125I]insulin to adrenal glands and suggest that IGF-I, rather than insulin, may play a critical role in the growth and development of the adrenal gland.
Pillion
D J
DJ
Dept. of Pharmacology, University of Alabama, Birmingham, AL 35294.
Yang
M
M
Grizzle
W E
WE
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D011972:Receptor, Insulin / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000378:metabolism*
D007328:Insulin; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D011972:Receptor, Insulin