title: [Experimental study of changes in microscopic characteristics and ability of secreting testosterone of aged SD rat leydig cells].
abstract: OBJECTIVE
  To research the changes in microscopic characteristics and ability of secreting testosterone between aged SD rat Leydig cells and young SD rat Leydig cells.
  
  
  METHODS
  The total and free serum testosterone levels of serum both young and aged rats were examined. The changes in microscopic characteristics between young and aged rat Leydig cells were observed under microscope and electron microscope. The testosterone secreted by cultured Leydig cells of stimulated by hCG and Forskolin both groups were detected.
  
  
  RESULTS
  A significant difference was found in both total and free testosterone levels between young and old rats (P < 0.05). Aged SD rat Leydig cells were observed smaller in volume and more markedly stained than young ones; The secretion ability of aged rat Leydig cells was found lower than that of young rat Leydig cells with or without hCG and Forskolin stimulation (P < 0.05).
  
  
  CONCLUSIONS
  The secreting index of aged SD rat Leydig cells is lower than that of young rat Leydig cells both in vivo and vitro, and the reason is the system of synthesizing testosterone is arrested.
authors.affiliation: Department of Urology, The First Affiliated Hospital, SUN Yat-sen University, Guangzhou, Guangdong 510080, China. dch0313@163.com
authors.forename: Chun-hua
authors.initials: CH
authors.lastname: Deng
authors.forename: Hai-bin
authors.initials: HB
authors.lastname: Guo
authors.forename: Jian-zhong
authors.initials: JZ
authors.lastname: Liu
mesh_terms: D000728:Androgens / Q000172:deficiency; D000818:Animals; D002478:Cells, Cultured; D007985:Leydig Cells / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013739:Testosterone / Q000378:metabolism*
chemical_list: D000728:Androgens; D013739:Testosterone; D011374:Progesterone