Nitric Oxide and Superoxide anion production during heparin-induced capacitation in cryopreserved bovine spermatozoa

RODRIGUEZ P; VALDEZ LB; ZAOBORNYJ T; BOVERIS A; BECONI M

REPRODUCTION IN DOMESTIC ANIMALS (1990)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 46 p. 74 - 81

0936-6768

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 x 10(7) cells), an enhancement in NO release (1.1 +/- 0.2 nmol/min x 10(7) cells), and a five-fold increase in O(2) (-) production (1.3 +/- 0.07 nmol/min x 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.