Nitric oxide and superoxide anion production during heparin-induced capacitation in cryopreserved bovine spermatozoa.
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.
Biological Chemistry, INITRA, School of Veterinary Science, University of Buenos Aires, Buenos Aires, Argentina. prodriguez@fvet.uba.ar
P C
PC
Rodriguez
L B
LB
Valdez
T
T
Zaobornyj
A
A
Boveris
M T
MT
Beconi
D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000662:veterinary; D006493:Heparin / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D010101:Oxygen Consumption; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D009569:Nitric Oxide; D006493:Heparin