Nitric oxide and superoxide anion production during heparin induced capacitation in criopreserved bovine spermatozoa

RODRIGUEZ PC; VALDEZ LB; ZAOBORNYJ T; BOVERIS A; BECONI MT

REPRODUCTION IN DOMESTIC ANIMALS (1990)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 46 p. 74 - 81

0936-6768

The aim of this work was to quantify NO, O2- and ONOO- production during heparin-induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin-dependent capacitation, O2 uptake, and NO production. Conversely, O2- 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 O2 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 O2- production (1.3 +/- 0.07 nmol/min x 10(7) cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O2- 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 O2 uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O2- 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.