title: Alteration of loperamide-induced prostate relaxation in high-fat diet-fed rats.
abstract: OBJECTIVE
  To investigate the change of loperamide-induced prostate relaxation in rats fed with high-fat diet (HFD).
  
  
  METHODS
  Adult male Wistar rats were divided into 2 groups: (1) control rats fed with normal chow and (2) rats fed with HFD for 6 months. The prostate was removed for histology study. Isolated prostate strips were hung in organ bath and precontracted with 1 μmol/L phenylephrine or 50 mmol/L KCl. The relaxation responses to loperamide 0.1 to 10 μmol/L were recorded. Western blotting analyses were performed for prostate μ-opioid receptors (MOR) and ATP-sensitive potassium (K(ATP)) channel proteins: sulfonylurea receptor (SUR) and inwardly rectifying potassium channel (Kir) 6.2 subunits.
  
  
  RESULTS
  Body weight, prostate weight, plasma levels of glucose, insulin, triglyceride, and cholesterol, as well as systolic blood pressure, were significantly increased in the HFD rats. Histology showed prostatic hyperplasia in the HFD rat prostate. Prostatic relaxation induced by loperamide was markedly reduced in HFD when compared to the control. Protein expressions of MOR, SUR, and Kir 6.2 were decreased in HFD-fed rats.
  
  
  CONCLUSIONS
  Loperamide-induced prostate relaxation is decreased in HFD rats due to reduced MOR and K(ATP) channel expressions.
authors.affiliation: Department of Urology, Chi-Mei Medical Center Jiali, Jiali Town, Tainan City, Taiwan.
authors.forename: Sheng-Lung
authors.initials: SL
authors.lastname: Hsu
authors.affiliation: Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
authors.forename: Hsien-Hui
authors.initials: HH
authors.lastname: Chung
authors.affiliation: Institute of Clinical Medical Sciences, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
authors.forename: I-Hung
authors.initials: IH
authors.lastname: Chen
authors.affiliation: Department of Urology, Medical College and Hospital, National Cheng Kung University, Tainan City, Taiwan ; National Cheng Kung University Hospital, 138 Sheng-Li Road, Tainan City 704, Taiwan.
authors.forename: Yat-Ching
authors.initials: YC
authors.lastname: Tong
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D059305:Diet, High-Fat; D005247:Feeding Behavior / Q000187:drug effects*; D066298:In Vitro Techniques; D008139:Loperamide / Q000494:pharmacology*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009929:Organ Size / Q000187:drug effects; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism; D011467:Prostate / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D020033:Protein Isoforms / Q000378:metabolism; D017208:Rats, Wistar; D017450:Receptors, Opioid, mu / Q000378:metabolism; D064233:Sulfonylurea Receptors / Q000378:metabolism; D013599:Systole / Q000187:drug effects; D000099161:Kcnj11 Channel
chemical_list: D008139:Loperamide; D024661:Potassium Channels, Inwardly Rectifying; D020033:Protein Isoforms; D017450:Receptors, Opioid, mu; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel