title: 17 beta-estradiol induces spermatogonial proliferation through mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) activity in the lizard (Podarcis s. sicula).
abstract: There are always more evidences indicating that 17beta-estradiol (E(2)) is necessary for normal male fertility. We have used a nonmammalian vertebrate model (the lizard Podarcis s. sicula) to investigate the regulation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity in the testis during the annual sexual cycle and to study whether E(2) exerts a role in the spermatogenesis through ERK1/2 activity. Immunocytochemistry analysis shows that ERK1/2 proteins are present in the nucleus of the spermatogonia (SPG), and in primary (I) spermatocytes (SPC). The annual E(2) profile shows a progressive increase during the active spermatogenesis (from April to June) and a peak in the month of August (spermatogonial mitosis). In parallel, ERK1/2 (molecular weight 44 and 42 kDa, respectively) are highly phosphorylated during the period of active spermatogenesis and in post-refractory period (August) compared with the winter stasis (from November to March). Present results demonstrate that E(2) treatment induces spermatogonial proliferation, possibly via the activation of ERK1/2, and this effect is counteracted by the antiestrogen ICI 182-780.
authors.affiliation: Dipartimento di Medicina Sperimentale F. Bottazzi II Università di Napoli, Naples, Italy. Paolo.Chieffi@unina2.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Chieffi
authors.forename: Luca
authors.initials: L
authors.lastname: Colucci D'Amato
authors.forename: Fabio
authors.initials: F
authors.lastname: Guarino
authors.forename: Gaetano
authors.initials: G
authors.lastname: Salvatore
authors.forename: Francesco
authors.initials: F
authors.lastname: Angelini
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D008116:Lizards / Q000502:physiology*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012621:Seasons; D013091:Spermatogenesis / Q000187:drug effects*; D013093:Spermatogonia / Q000187:drug effects* / Q000502:physiology; D013737:Testis / Q000166:cytology / Q000201:enzymology / Q000502:physiology
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D004958:Estradiol; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases