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Nitric Oxide and Superoxide Anion Production During Heparin‐Induced Capacitation in Cryopreserved Bovine Spermatozoa
Author(s) -
Rodriguez PC,
Valdez LB,
Zaobornyj T,
Boveris A,
Beconi MT
Publication year - 2011
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2010.01583.x
Subject(s) - capacitation , superoxide , heparin , sperm , chemistry , incubation , biochemistry , peroxynitrite , nitric oxide , andrology , biology , enzyme , endocrinology , in vitro , medicine
Contents The aim of this work was to quantify NO, O 2 − and ONOO − production during heparin‐induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin‐dependent capacitation, O 2 uptake, and NO production. Conversely, O 2 − production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O 2 consumption (5.9 ± 0.6 nmol/min × 10 7 cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 10 7 cells), and a five‐fold increase in O 2 − production (1.3 ± 0.07 nmol/min × 10 7 cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O 2 − generation and the second‐order rate constant of the reaction between these species. To conclude, heparin‐induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O 2 uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O 2 − production by a membrane‐bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation.