title: Quantitative (stereological) study of incomplete spermatogenic suppression induced by testosterone undecanoate injection in rats.
abstract: OBJECTIVE
  To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate (TU) treatment.
  
  
  METHODS
  Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector.
  
  
  RESULTS
  In response to TU treatment, the numbers of non-type B spermatogonia, type B spermatogonia and late elongated spermatids per testis were reduced to 51 %, 66 % and 14 % of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51 % - 65 % of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0 % of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged.
  
  
  CONCLUSIONS
  Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gonadotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular testosterone levels.
authors.affiliation: Morphometric Research Laboratory, North Sichuan Medical College, Nanchong, Sichuan 637007. zwyang@mail.nctele.com.
authors.forename: Zheng-Wei
authors.initials: ZW
authors.lastname: Yang
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Xing-Hai
authors.initials: XH
authors.lastname: Wang
authors.forename: Jian-Sun
authors.initials: JS
authors.lastname: Tong
authors.forename: Gui-Yuan
authors.initials: GY
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D003864:Depression, Chemical; D007985:Leydig Cells / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000187:drug effects; D013076:Sperm Count; D013087:Spermatids / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects*; D013739:Testosterone / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology*
chemical_list: D013739:Testosterone; C010792:testosterone undecanoate