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Journal of Diabetes Research
Volume 2015 (2015), Article ID 538529, 18 pages
Research Article

Influence of Melatonin on the Proliferative and Apoptotic Responses of the Prostate under Normal and Hyperglycemic Conditions

1Department of Cell Biology, Institute of Biology, UNICAMP, Avenue Bertrand Russel, 6109 Campinas, SP, Brazil
2Department of Clinical Sciences, Division of Urological Research, Skåne University Hospital, Lund University, 205 02 Malmö, Sweden
3Department of Biology, Institute of Biosciences, Humanities and Exact Sciences, UNESP, São José do Rio Preto, SP, Brazil

Received 13 May 2015; Revised 22 June 2015; Accepted 24 June 2015

Academic Editor: Hiroshi Okamoto

Copyright © 2015 Marina G. Gobbo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The antitumor properties of melatonin (MLT) are known for prostate cancer cells. This study investigated whether MLT affects prostate maturation and interferes with tissue injuries induced by diabetes. MLT was administered to Wistar rats from 5 weeks of age in the drinking water (10 μg/kg b.w.), and diabetes was induced at the 13th week by streptozotocin (4.5 mg/100g b.w., i.p.). The animals were euthanized in the 14th and 21st weeks. MLT reduced the immunostained cells for androgen receptor (AR) by 10% in younger rats. Diabetes decreased cell proliferation and increased apoptosis. MLT treatment impeded apoptosis and augmented proliferation and PCNA content in prostate following long-term diabetes due to restoration of testosterone levels and expression of melatonin receptor type 1B. The effect of MLT (500 µM, 5 mM, and 10 mM) on androgen-dependent (22Rv1) and androgen-independent (PC3) cancer cells and human prostate epithelial cells (PNTA1) under normal and hyperglycemic conditions (HG, 450 mg/dL) was analyzed. Contrary to PNTA1 and 22Rv1 cells, MLT improved the proliferation of PC3 cells in hyperglycemic medium. The combined data indicated that MLT had proliferative and antiapoptotic effects in prostate cells subjected to HG levels and it seems to involve specific MLT pathways rather than AR.