Effect of L-carnitine and L-aminocarnitine on calcium transport, motility, and enzyme release from ejaculated bovine spermatozoa.
Experiments were performed to further elucidate the role of gamma-amino-beta-hydroxybutyric acid trimethylbetaine (carnitine) on the metabolism and functions of spermatozoa. Addition of 20 mM L-carnitine to suspensions of ejaculated bovine spermatozoa resulted in an increase of cellular calcium transport, whereas 20 mM L-aminocarnitine (an inhibitor of carnitine palmitoyltransferase) caused an inhibition of this process. Both L-carnitine and L-aminocarnitine inhibited the progressive motility of spermatozoa, and the oxygen consumption as well as the release of the enzymes hyaluronidase and glutamate-oxaloacetate transaminase from spermatozoa. Labeled carnitine was rapidly taken up by spermatozoa by a process strongly dependent on temperature and extracellular concentration of carnitine. It is concluded that the effects produced by high concentrations of carnitine or aminocarnitine are mainly due to interactions of these compounds with the cellular membranes of spermatozoa.
Deana
R
R
Department of Biological Chemistry, University of Padova, Italy.
Rigoni
F
F
Francesconi
M
M
Cavallini
L
L
Arslan
P
P
Siliprandi
N
N
D000217:Acyltransferases / Q000037:antagonists & inhibitors*; D000818:Animals; D001622:Betaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics*; D002331:Carnitine / Q000494:pharmacology*; D002333:Carnitine Acyltransferases / Q000037:antagonists & inhibitors*; D002417:Cattle; D004542:Ejaculation; D006821:Hyaluronoglucosaminidase / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects* / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D000637:Transaminases / Q000378:metabolism*
D001622:Betaine; C045761:emeriamine; D000217:Acyltransferases; D002333:Carnitine Acyltransferases; D000637:Transaminases; D006821:Hyaluronoglucosaminidase; D002331:Carnitine; D002118:Calcium