title: [Effect of thyroid hormone on protein kinase C signal pathway in cardiac myocytes and fibroblasts of rats in vitro].
abstract: OBJECTIVE
  To study the effect of thyroid hormone on protein kinase C activity and isoprotein expressions in cardiac myocytes and fibroblasts of rats in vitro.
  
  
  METHODS
  Cardiac myocytes and fibroblasts were cultured according to the method of Simpson. Cells were pretreated with 1% newborn calf serum (NCS) or Angiotensin II (Ang II) for 24 hours, then Triiodothyronine (T3) was added to the culture medium and the culture was kept for another 48 hours. The protein kinase C activation were measured by PepTaga non-radioactive PKC assay, and the expressions of PKC alpha and PKC epsilon were detected by Western blot method.
  
  
  RESULTS
  At the condition of 1% NCS culture medium, T3 could inhibit PKC activity and PKC epsilon expression in cardiac myocytes significantly, but the expression of PKC alpha in cardiac myocytes was not influenced by T3. In cardiac fibroblasts, neither PKC activity nor PKC alpha and PKC epsilon expressions was influenced by T3. When cells were pretreated with Ang II for 24 hours, PKC activities in cardiac myocytes and fibroblasts were increased significantly, and PKC epsilon expressions in cardiac myocytes were also markedly increased. Following a T3 treatment, PKC activity and PKC epsilon expression in cardiac myocytes were markedly decreased, but PKC activity in cardiac fibroblasts was not changed.
  
  
  CONCLUSIONS
  Whether at the condition of 1% NCS medium or in a pretreatment with Ang II, thyroid hormone could inhibit the PKC activity and PKC epsilon expression in cardiac myocytes. The influence of thyroid hormone on the PKC signal pathway in cardiac myocyte may be involved in many pathophysiological progress of myocardium.
authors.affiliation: Department of Pathophysiology, Medical College of Wuhan University, Wuhan 430071, China.
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Wang
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Ouyang
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Liu
authors.forename: Han-Qiao
authors.initials: HQ
authors.lastname: Zheng
authors.forename: Lei
authors.initials: L
authors.lastname: Wei
authors.forename: Jing-Wei
authors.initials: JW
authors.lastname: Yang
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Hai-Lu
authors.initials: HL
authors.lastname: Yang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D032386:Myoblasts, Cardiac / Q000187:drug effects / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D013963:Thyroid Hormones / Q000494:pharmacology*
chemical_list: D013963:Thyroid Hormones; D011493:Protein Kinase C