title: A caged progesterone analog alters intracellular Ca2+ and flagellar bending in human sperm.
abstract: Progesterone is a physiological agonist for mammalian sperm, modulating its flagellar movement and facilitating the acrosome reaction. To study the initial action of progesterone, we developed a caged analog with a photosensitive group: nitrophenylethanediol, at position 20. Using this compound combined with stroboscopic illumination, we performed Ca(2)(+) imaging of human spermatozoa and analyzed the effects of progesterone on the intracellular Ca(2)(+) concentration ([Ca(2)(+)](i)) of beating flagella for the first time. We observed a transient [Ca(2)(+)](i) increase in the head and the flagellum upon photolysis of the caged progesterone and an increase in flagellar curvature. Detailed kinetic analysis revealed that progesterone elicits an increase in the [Ca(2)(+)](i) immediately in the flagellum (mid-piece and principal piece), thereafter in the head with a short time lag. This observation is different from the progesterone-induced Ca(2)(+) mobilization in mouse spermatozoa, where the Ca(2)(+) rise initiates at the base of the sperm head. Our finding is mostly consistent with the recent discovery that progesterone activates CatSper channels in human spermatozoa, but not in mouse spermatozoa.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apdo Postal 510-3, Cuernavaca, Morelos 62250, Mexico.
authors.forename: M Rocio
authors.initials: MR
authors.lastname: Servin-Vences
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Tatsu
authors.forename: Hisanori
authors.initials: H
authors.lastname: Ando
authors.forename: Adán
authors.initials: A
authors.lastname: Guerrero
authors.forename: Noboru
authors.initials: N
authors.lastname: Yumoto
authors.forename: Alberto
authors.initials: A
authors.lastname: Darszon
authors.forename: Takuya
authors.initials: T
authors.lastname: Nishigaki
mesh_terms: D002118:Calcium / Q000032:analysis*; D015220:Calcium Channels / Q000187:drug effects; D005456:Fluorescent Dyes; D006801:Humans; D008297:Male; D009578:Nitrobenzenes / Q000737:chemistry; D010782:Photolysis; D011374:Progesterone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013077:Sperm Head / Q000737:chemistry / Q000187:drug effects; D013082:Sperm Tail / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D013094:Spermatozoa / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology
chemical_list: C438823:CATSPER1 protein, human; D015220:Calcium Channels; D005456:Fluorescent Dyes; D009578:Nitrobenzenes; D011374:Progesterone; D002118:Calcium