Molecular and Cellular Biochemistry

, Volume 282, Issue 1–2, pp 187–191 | Cite as

The effect of systemic leptin administration on aorta smooth muscle responses in diabetic rats

  • Çiğdem Özer
  • Şebnem Gülen
  • Ergin Dileköz
  • Aydan Babül
  • Z. Sevim Ercan


Leptin produces effects in central nervous system and peripheral tissues via its specific receptors. Leptin also stimulates nitric oxide release in a concentration-dependent manner. In this study, our aim was to test the hypothesis that whether leptin has a modulatory role on endothelium or smooth muscle function in streptozotocin (STZ)-induced diabetic rats. Wistar-Albino rats were divided into four groups: 1 – Control, 2 – Diabetic, 3 – Control + leptin and 4 – Diabetic + leptin. Experimental diabetes was produced by intraperitoneal injection of a single dose of STZ (55 mg/kg). Diabetes was determined by increased fasting blood glucose level on the 7th day of the experiment. Leptin (0.1 mg/kg/day) was administered intraperitoneally for 5 days. At the end of the 5th day, thoracic aortas were isolated and phenylephrine (Phe)-induced contractions and acetylcholine (ACh)-induced relaxations of each group were estimated. In diabetic rats, Phe-induced contractility was increased (p < 0.05). Leptin pre-treatment increased the Phe-induced contractility significantly in aortic rings obtained from diabetic rats (p < 0.05). In normal rats, leptin administration produced only a slight and non-significant increase in Phe-induced contractions. Although the relaxant responses were decreased in diabetic rats, leptin administration enhanced the ACh-induced relaxation in both normal and diabetic animals significantly. As a conclusion; chronic leptin pre-treatment caused a significant increase both in Phe-induced contractions and ACh-induced Endothelial-Derived Relaxing Factor (EDRF)/Nitric oxide-mediated relaxations in the aortic rings isolated from streptozotocin-induced diabetic rats. This peptide hormone caused a significant increase in the relaxations obtained by ACh while not inducing a significant alteration in the contractile effect of Phe in control rats.

Key words

aorta diabetes leptin streptozotocin 


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Copyright information

© Springer Science + Business Media, Inc. 2006

Authors and Affiliations

  • Çiğdem Özer
    • 1
  • Şebnem Gülen
    • 2
  • Ergin Dileköz
    • 3
  • Aydan Babül
    • 1
  • Z. Sevim Ercan
    • 3
  1. 1.Department of Physiology, Faculty of MedicineGazi UniversityBeşevler, AnkaraTurkey
  2. 2.Department of Physiology, Faculty of MedicineBaşkent UniversityAnkaraTurkey
  3. 3.Department of Pharmacology, Faculty of MedicineGazi UniversityBeşevler, AnkaraTurkey

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