title: Estrogen promotes germ cell and seminiferous tubule development in the baboon fetal testis.
abstract: The foundation for development of the male reproduction system occurs in utero, but relatively little is known about the regulation of primate fetal testis maturation. Our laboratories have shown that estrogen regulates key aspects of the physiology of pregnancy and fetal development. Therefore, in the present study, we characterized and quantified germ cells and Sertoli cells in the fetal baboon testis in late normal gestation (i.e., Day 165; term is 184 days) and in baboons administered the aromatase inhibitor letrozole throughout the second half of gestation to assess the impact of endogenous estrogen on fetal testis development. In untreated baboons, the seminiferous cords were comprised of undifferentiated (i.e., type A) spermatogonia classified by their morphology as dark (Ad) or pale (Ap), gonocytes (precursors of type A spermatogonia), unidentified cells (UI), and Sertoli cells. In letrozole-treated baboons, serum estradiol levels were decreased by 95%. The number per milligram of fetal testis (x10(4)) of Ad spermatogonia (0.42 +/- 0.11) was 45% lower (P = 0.03), and that of gonocytes (0.58 +/- 0.06) and UI (0.45 +/- 0.12) was twofold greater (P < 0.01 and P = 0.06, respectively), than in untreated baboons. Moreover, in the seminiferous cords of estrogen-deprived baboons, the basement membrane appeared fragmented, the germ cells and Sertoli cells appeared disorganized, and vacuoles were present. We conclude that endogenous estrogen promotes fetal testis development and that the changes in the germ cell population in the estrogen-deprived baboon fetus may impair spermatogenesis and fertility in adulthood.
authors.affiliation: Department of Obstetrics, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. ealbrech@umaryland.edu
authors.forename: Eugene D
authors.initials: ED
authors.lastname: Albrecht
authors.forename: Malcolm V
authors.initials: MV
authors.lastname: Lane
authors.forename: Gary R
authors.initials: GR
authors.lastname: Marshall
authors.forename: Istvan
authors.initials: I
authors.lastname: Merchenthaler
authors.forename: David R
authors.initials: DR
authors.lastname: Simorangkir
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Pohl
authors.forename: Tony M
authors.initials: TM
authors.lastname: Plant
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Pepe
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D047072:Aromatase Inhibitors / Q000494:pharmacology; D001485:Basement Membrane / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D004967:Estrogens / Q000172:deficiency / Q000502:physiology*; D005260:Female; D020567:Fetal Weight / Q000187:drug effects; D005640:Follicle Stimulating Hormone / Q000097:blood; D000077289:Letrozole; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009570:Nitriles / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D048530:Papio anubis / Q000196:embryology*; D011247:Pregnancy; D011897:Random Allocation; D012671:Seminiferous Tubules / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D018709:Statistics, Nonparametric; D013737:Testis / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology / Q000648:ultrastructure; D013739:Testosterone / Q000097:blood; D014230:Triazoles / Q000494:pharmacology
chemical_list: D047072:Aromatase Inhibitors; D018797:Cell Cycle Proteins; D004967:Estrogens; D009570:Nitriles; D014230:Triazoles; D013739:Testosterone; D004958:Estradiol; D000077289:Letrozole; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D053148:Caspase 3