Effect of protein kinase C on guinea pig sperm acrosome reaction induced by progesterone.
OBJECTIVE
To investigate the effect of protein kinase C (PKC) on the guinea pig sperm acrosome reaction (AR) induced by progesterone (P4).


METHODS
Guinea pig spermatozoa were preincubated in MCM-Ca2+ DF medium at 38.5 degrees C under 5% CO2/air for 6-6.5 h for capacitation, and were then washed through a three-step gradient Percoll, resuspended in MCM-Ca2+ DF and adjusted to 5 x 10(9) cells/L. The AR was assessed by means of phase-contrast microscopy (expressed as percent of AR) 15 min after different reagents were added.


RESULTS
In the presence of Ca2+ 2 mmol/L, phorbol 12,13-dibutyrate (PDB) or the permanent synthetic diacylglycerol, 1-oleoyl-2-acetyl-sn-glycerol (OAG) initiated the AR of spermatozoa in a concentration-related manner, whereas staurosporine (STA) exhibited an inhibition of the AR. PDB and OAG significantly enhanced P4-induced AR that was greater than that treated with either agonist separately. STA markedly inhibited the P4-induced AR. The AR induced by PDB was completely antagonized by inclusion of egtazic acid. Also, both egtazic acid and nifedipine antagonized the AR induced by P4 and PDB + P4. In addition, neomycin also prevented the P4-induced AR. This effect could be partly reversed by PDB.


CONCLUSIONS
Activation or inhibition of PKC significantly plays an important role in the signal transduction pathway for the physiological AR.
Chen
W Y
WY
Zhejiang Academy of Medical Sciences, Hangzhou 310013, China.
Yuan
Y Y
YY
Shi
Q X
QX
Zhang
X Y
XY
D020101:Acrosome Reaction / Q000187:drug effects*; D000818:Animals; D004075:Diglycerides / Q000494:pharmacology; D006168:Guinea Pigs; D008297:Male; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction; D013094:Spermatozoa / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology
D004075:Diglycerides; D015240:Phorbol 12,13-Dibutyrate; D011374:Progesterone; C038237:1-oleoyl-2-acetylglycerol; D011493:Protein Kinase C; D019311:Staurosporine