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)

Growth hormone (GH) and insulin-like growth factor I (IGF-I) exert a variety of actions in renal tissue. To shed light upon the renal GH-IGF I axis we have characterized the cell biology of GH and IGF I in two parts of the nephron that are targets for these peptides, proximal tubule and collecting duct. Receptors for both GH and IGF I are present in the basolateral membrane of the renal proximal tubular cell. GH activates phospholipase C and IGF I stimulates phosphorylation of its receptor at this site. Both peptides directly enhance gluconeogenesis in proximal tubule. GH stimulates IGF I gene expression in collecting duct. IGF I of collecting duct origin could act as a paracrine growth factor in other portions of the nephron. IGF I may be causative of renal hypertrophy that occurs in the settings of hypersomatotropism, unilateral nephrectomy (compensatory hypertrophy) and diabetes mellitus.
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PMID:Renal cellular biology of growth hormone and insulin-like growth factor I. 165 79

The renal collecting duct is a site of insulin-like growth factor I (IGF I) synthesis. Epidermal growth factor (EGF) is also synthesized within the kidney in the thick ascending limb of Henle's loop and the distal tubule. EGF has been shown to regulate IGF I expression in nonrenal tissues. To shed light upon a role of EGF in intrarenal regulation of IGF I gene expression, plasma membranes prepared from collecting ducts isolated from rat kidney and collecting ducts themselves were incubated in the presence and absence of recombinant human EGF (hEGF). hEGF enhanced phospholipase C activity in collecting duct plasma membranes establishing the potential for EGF signal transduction at this site. Inclusion of hEGF in suspensions of collecting ducts increased production of immunoreactive IGF I in a concentration-dependent manner. Production was stimulated significantly by addition of 10(-8) or 10(-6) M hEGF to suspensions for 2 h. Levels of IGF I mRNA in collecting ducts were increased 2.8-fold after incubation with 10(-6) M hEGF in vitro. Our findings demonstrate a direct action of hEGF to enhance collecting duct IGF I gene expression in vitro. Such enhancement is likely to reflect an effect of EGF to stimulate IGF I production in the collecting duct of the intact kidney. Since EGF is produced in kidney, our findings are consistent with intrarenal paracrine regulation of IGF I gene expression by EGF.
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PMID:Insulin-like growth factor I gene expression in isolated rat renal collecting duct is stimulated by epidermal growth factor. 198 6

To determine whether growth hormone (GH) directly stimulates insulin-like growth factor I (IGF I) gene expression in renal collecting duct, plasma membranes prepared from collecting ducts isolated from rat kidney, and collecting ducts themselves were incubated in presence and absence of GH. GH enhanced phospholipase C activity in collecting duct plasma membranes establishing the potential for GH-signal transduction. Inclusion of GH in suspensions of collecting ducts increased production of immunoreactive IGF I in a time-dependent and concentration-dependent manner. Production was stimulated significantly by addition of 10(-10), 10(-8), or 10(-6) M GH to suspensions for 2 h. IGF I produced in isolated collecting ducts was released into the suspending media. Levels of IGF I mRNA in collecting ducts were increased 2.8-fold after incubation with 10(-6) M GH in vitro. IGF I of collecting duct origin was indistinguishable from recombinant human IGF I in terms of its size and receptor-binding characteristics. Our findings demonstrate a direct action of GH to enhance collecting duct IGF I gene expression in vitro. Such enhancement is likely to reflect the mechanism by which GH stimulates renal IGF I production in intact kidney.
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PMID:Growth hormone stimulates IGF I gene expression in isolated rat renal collecting duct. 239 72

Growth hormone (GH) exerts a variety of metabolic and anabolic effects on skeletal and soft tissues including kidney. Some of these actions are mediated directly, whereas others result from GH-dependent synthesis and release of polypeptide growth factors designated insulin-like growth factors (IGFs). Receptors for GH are present in proximal tubule and GH directly stimulates gluconeogenesis at this site. IGF receptors are found in glomerulus and proximal tubule. Mechanisms for signal transduction by GH and IGFs have been characterized using proximal tubular basolateral membranes. IGFs regulate metabolic and transport processes in cultured glomerular mesangial cells and in isolated proximal tubular cells. IGF I is synthesized in cultured mesangial cells and is produced in a GH-dependent manner in cortical and medullary collecting duct. Evidence has accumulated that IGF I of renal origin functions as a paracrine growth factor in the settings of GH-induced hypertrophy and compensatory hypertrophy of the kidney, and in the setting of proximal tubular regeneration following ischemic injury. IGFs are embryonal mitogens and IGF II may act as a transforming agent for Wilms' tumor. Further characterization of the GH-IGF axis in kidney will provide additional insights into the roles of these peptides as regulators of renal function, growth, and development.
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PMID:The growth hormone-insulin-like growth factor axis in kidney. 267 42

To address the question of insulin-like growth factor (IGF) I localization and synthesis in kidney, we used two complementary experimental approaches: immunohistochemistry of fixed paraffin-embedded rat kidney sections; and measurement of IGF I mRNA in isolated components of the rat nephron, using a highly sensitive and specific solution hybridization assay. Immunostainable IGF I was localized exclusively to principal cells of cortical and medullary collecting ducts. Administration of growth hormone to hypophysectomized rats for 8 d resulted in enhanced immunohistochemical staining of IGF I within collecting ducts, but no detectable IGF I in other portions of the nephron. The abundance of IGF I mRNA was 7-12-fold higher in isolated papillary collecting ducts than in proximal tubules or glomeruli, and was enriched 10-fold compared with whole kidney. Our data demonstrate colocalization of IGF I and IGF I mRNA in the collecting duct, consistent with focal expression of the IGF I gene at this site.
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PMID:Focal expression of insulin-like growth factor I in rat kidney collecting duct. 341 71