Reproduction in Domestic Animals

Endocrine Regulation of Porcine Spermatogenesis 285(a)(b)(c)(d)Fig. 5. Morphological analysis ofgerm cell populations in porcinetestis tissue grafts. Tubule crosssectionsrepresenting mostadvanced germ cell type: (a) spermatocytesa, (b) round spermatidsb, (c, d) elongating spermatids c.Scale bars = 50 lm(a) (b) (c)Fig. 6. Morphological analysis of(a) non-frozen control and (b)cryopreserved porcine testis tissueprior to grafting. (c) Morphometricevaluation of germ cell differentiationin control and frozen porcinetestis tissue after grafting(20 weeks) represented by percentageof seminiferous tubule crosssectionscontaining spermatogonia[Gonia], spermatocytes [Cytes]and spermatids [Tids] as mostadvanced cell type. There were nosignificant differences betweenmeans (p > 0.05). Micrographs of(d) control and (e). Cryopreservedporcine testis tissue following thegrafting period Bar = 50 lm(d)(e)In vivo studies have suggested the potential tomanipulate establishment of Sertoli cell populations innon-human primates (Sharpe et al. 2000), rodents (Orthet al. 1988), bulls (Majdic et al. 1998) and boars(Lunstra et al. 2003; Nonneman et al. 2005). In anattempt to increase Sertoli cell number and pubertaltestis size similar to rodents, researchers used theapproach of inducing post-natal hypothyroidism in 21-day-old, pre-pubertal boars (Klobucar et al. 2003). Yet,it was concluded that post-natal hypothyroidism doesnot affect testis development, Sertoli cell number orsperm production in boars, despite observations ofporcine Sertoli cells expressing markers of proliferatingcells until 4 months of age (Klobucar et al. 2003).Interestingly, Sertoli cells and gonocytes were immunopositivefor nuclear AR protein in the testes of allÓ 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag