296 insulin receptors in the developing fetal lung

ABSTRACT Insulin affects metabolism through a receptor mediated mechanism. Since insulin has been associated with pulmonary metabolism, insulin receptor concentrations and binding affinities

were studied in fetal lung development. Lung membrane preparations from fetal rats 15 to 21 days gestation were incubated with porcine 125I-insulin. Binding equilibrium was reached at 5

hours at 4°C; maximum binding was achieved at pH 7.8. Insulin binding capacities and affinities were calculated by the method of least squares, assuming 1 ligand binds to 2 sites (Feldman,

H.A., Anal. Biochem. 48: 317, 1972). The binding data exhibited a biphasic curve when analyzed by Scatchard analysis. The binding capacities of the membranes increased linearly from 175 ± 20

fmoles insulin bound/mg membrane protein at 15 days gestation to 517 ± 42 fmoles insulin bound/mg protein at 21 days gestation. This increase was even greater when expressed per mg DNA (105

± 9 fmoles insulin bound/mg DNA at 15 days gestation vs. 465 ± 42 fmoles bound/mg DNA at 21 days gestation. In contrast, both the high and low association constants remained unchanged from

15 days (high affinity = 1.9 ± .4 nM-1; low affinity = 0.03 ± .01 nM-1) to 21 days gestational age (high affinity 1.5 ± .5 nM-1; low affinity = 0.02 ± .01 nM-1). Thus, the developing fetal

lung has an increased capacity to bind insulin as it matures, and this increase is a function of receptor number, not a change in receptor affinity. ARTICLE PDF AUTHOR INFORMATION AUTHORS

AND AFFILIATIONS * NICHD, NIH, Bethesda, 20205, MD R E Ulane, J E Graeber, J W Hansen, L Liccini & M Cornblath Authors * R E Ulane View author publications You can also search for this

author inPubMed Google Scholar * J E Graeber View author publications You can also search for this author inPubMed Google Scholar * J W Hansen View author publications You can also search

for this author inPubMed Google Scholar * L Liccini View author publications You can also search for this author inPubMed Google Scholar * M Cornblath View author publications You can also

search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Ulane, R., Graeber, J., Hansen, J. _et al._ 296 INSULIN

RECEPTORS IN THE DEVELOPING FETAL LUNG. _Pediatr Res_ 15 (Suppl 4), 489 (1981). https://doi.org/10.1203/00006450-198104001-00307 Download citation * Issue Date: 01 April 1981 * DOI:

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