Abundant expression of parathyroid hormone-related protein in primary rat aortic smooth muscle cells accompanies serum-induced proliferation
- T Hongo 1, J Kupfer , H Enomoto , B Sharifi , D Giannella-Neto , J S Forrester , F R Singer , D Goltzman , G N Hendy , C Pirola
- 1Department of Medicine, University of California, Los Angeles 90048.
- 0Department of Medicine, University of California, Los Angeles 90048.
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View abstract on PubMed
Summary
This summary is machine-generated.Parathyroid hormone-related protein (PTHrP) is expressed in rat aortic smooth muscle cells and its messenger RNA (mRNA) is induced by serum and vasoactive peptides, suggesting a local role in vascular regulation.
Area Of Science
- Vascular Biology
- Molecular Endocrinology
Background
- Parathyroid hormone-related protein (PTHrP) is known to cause hypercalcemia in malignancy.
- PTHrP, similar to parathyroid hormone (PTH), possesses vasodilatory properties.
- Recent findings indicate PTHrP presence in normal tissues.
Purpose Of The Study
- To investigate the expression and regulation of PTHrP mRNA in cultured rat aortic smooth muscle cells (SMC).
- To determine the role of PTHrP as a local modulator in vascular smooth muscle.
Main Methods
- Cultured rat aortic smooth muscle cells (SMC) were used to study PTHrP mRNA expression.
- Serum induction, time- and concentration-dependency, and effects of specific agents (dexamethasone, growth factors, vasoactive peptides) were analyzed.
- PTHrP protein levels were assessed by immunocytochemistry and radioimmunoassay.
- Gene transcription was evaluated using actinomycin D and cycloheximide.
Main Results
- PTHrP mRNA is expressed in SMC and significantly induced by serum in a time- and dose-dependent manner.
- Serum induction requires new protein synthesis and is blunted by dexamethasone.
- Vasoactive peptides (endothelin, norepinephrine, thrombin) stimulated PTHrP expression, while PDGF and IGF-I had no effect.
- Exogenous PTHrP did not affect SMC DNA synthesis.
Conclusions
- PTHrP mRNA abundance and its regulation in SMC suggest a significant role as a local vascular smooth muscle modulator.
- PTHrP may play a role in regulating vascular tone and function.
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