title: Detection and localization of two constitutive NOS isoforms in bull spermatozoa.
abstract: Bull spermatozoa were examined for the presence and localization of constitutive Nitric Oxide Synthase (NOS), as nitric oxide (NO) is involved in calcium-dependent capacitation. In bull spermatozoa, NO generation is enhanced by l-arginine (3 microm) and abolished by the NOS-inhibitor N-nitro-l-arginine methyl ester (l-NAME). In addition, presence of NOS in bull spermatozoa was verified by immunohistochemistry, revealing the existence of both neuronal NOS (nNOS) and endothelial NOS (eNOS) immunoreaction. These findings were confirmed by Western blot technique, showing immunoreactive bands at 161 kDa (nNOS) and 133 kDa (eNOS). Confocal laser microscopy localized nNOS related immunofluorescence at the acrosome cap of sperms and their flagellum-mainpart. This technique also identified eNOS staining spread over the spermatozoan head. In conclusion, immunohistochemistry, Western blot technique, and NO generation suggest the presence of n- and eNOS in bull spermatozoa.
authors.affiliation: Institute of Pharmacology, Toxicology and Pharmacy, University of Munich, Königinstr.16, D-80539 Munich, Germany. meiser@pharmtox.vetmed.uni-muenchen.de
authors.forename: H
authors.initials: H
authors.lastname: Meiser
authors.forename: R
authors.initials: R
authors.lastname: Schulz
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D002417:Cattle; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D018613:Microscopy, Confocal / Q000662:veterinary; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000737:chemistry / Q000302:isolation & purification*; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III