Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Quantitative ligand binding autoradiography and in situ hybridization were employed to analyze [125I]insulin-like growth factor-I ([125I] IGF-I) and [125I]IGF-II-binding sites in human kidney sections. Binding sites for both ligands were concentrated in the inner medulla and glomeruli, with low levels present in the tubulo-interstitial cortex. Competition with cold IGF-I, IGF-II, and insulin was used to determine nonspecific binding and differentiate binding of ligands to the IGF-I and IGF-II receptors and IGF-binding proteins (IGFBPs). Nonspecific binding was less than 20% of the total for both ligands. Insulin (10(-5) mol/L), which binds to the IGF-I receptor, but not to the IGF-II receptor or IGFBPs, displaced 39 +/- 8% of [125I]IGF-I binding in glomeruli, 60 +/- 7% in the tubulo-interstitial cortex, and 32 +/- 7% in the medulla. Insulin produced no detectable decrease in [125I]IGF-II binding in any region. IGF-I (10(-8) mol/L), which binds strongly to IGFBPs, but not appreciably to the IGF-II receptor, produced reductions of 46 +/- 9%, 35 +/- 8%, and 39 +/- 12% in [125I]IGF-II binding in glomeruli, tubulo-interstitial cortex, and medulla, respectively. In situ hybridization showed that IGFBP-1-5 mRNAs were all expressed in glomeruli. IGFBP-2 mRNA was abundant in medullary collecting duct epithelium, whereas IGFBP-3, -4, and -5 mRNAs were localized in interstitial and vascular cells throughout the kidney. IGF-I and -II receptor mRNAs were widely distributed in renal epithelium. The abundance of local IGFBP gene expression was positively correlated with insulin-nondisplaceable IGF binding in specific kidney regions. In summary, [125I]IGF-I binding appears to be partitioned largely to IGFBPs in glomeruli and largely to the IGF-I receptor in the tubulo-interstitial cortex, with binding in the medulla more evenly divided. The proportion and regional distribution of [125I]IGF-II binding to IGFBPs are similar, but the balance appears to be primarily associated with the IGF-II, rather than the IGF-I, receptor. Finally, this study shows that [125I]IGF binding autoradiography combined with in situ hybridization can be used to localize and potentially quantitative expression of IGFBPs in tissue sections.
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PMID:Partition of insulin-like growth factor (IGF)-binding sites between the IGF-I and IGF-II receptors and IGF-binding proteins in the human kidney. 750 21

We studied the renal expression of the insulin-like growth factor (IGF) system to gain a better perspective of its potential role in the hyperplastic adaptation of the distal nephron to potassium deficiency. Rats were pair fed 1% or 0.002% potassium diets for periods up to 10 days. IGF-I mRNA was diminished in potassium-deficient rats within 4 days, whereas mRNA for IGF binding protein-1 (IGFBP-1), a collecting duct-associated protein, was increased by day 7. At day 10 mRNA for IGFBP-1 in potassium-deficient animals averaged 2.07 +/- 0.53 (mean +/- SD, relative densitometry units) compared with 0.89 +/- 0.26 in control rats (n = 4, P = 0.002). Conversely, IGFBP-3, a binding protein whose mRNA has been localized to the interstitial compartment, averaged 2.40 +/- 0.02 in potassium-deficient rats and 4.77 +/- 0.05 in controls (n = 4, P < 0.03) at day 10 of treatment. Immunohistochemistry performed using a specific IGFBP-1 antibody revealed hyperplasia of distal nephron segments along with an increase in IGFBP-1 in potassium-depleted rats. These data suggest that IGFBP-1 may play an important role in the control of cellular adaptations in the hypokalemic rat kidney either directly by influencing cell migration or indirectly by localizing IGF-I to the distal nephron.
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PMID:Expression of the insulin-like growth factor system in the hypokalemic rat kidney. 917 78