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Diacylglycerol and Alkylacylglycerol Stimulate Ram Sperm Phospholipase A2

E R Roldan, R Martinez-Dalmau, F Mollinedo

Int J Biochem. 1994 Jul;26(7):951-8.

PMID: 8063019

Abstract:

1. We have investigated the susceptibility of ram sperm phospholipase A2 (PLA2) to stimulation by diacyl- and alkylacylglycerols and by monoacyl- and monoalkylglycerols. 2. PLA2 activity in sonicates from ram spermatozoa was enhanced when 1-stearoyl-2-arachidonoyl-sn-glycerol, the diacylglycerol usually generated by polyphosphoinositide breakdown, was added to a radioactive phosphatidylcholine substrate; the effect was time- and Ca(2+)-dependent. 3. Both diacyl- and alkylacylglycerol considerably enhanced PLA2 activity; 1-O-hexadecyl-2-O-methyl-rac-glycerol, however, only showed slight stimulatory ability. 4. The monoradylglycerols 1-monohexadecanoyl-rac-glycerol, 2-monohexadecanoylglycerol, and 1-O-hexadecyl-sn-glycerol had very little effect on the enzyme's activity. 5. Exposure of spermatozoa to 1-oleoyl-2-acetyl-sn-glycerol (OAG) or 1-O-hexadecyl-2-acetyl-rac-glycerol (1-O-C16/2-C2), when cells were stimulated with the ionophore A23187 and Ca2+, resulted in higher PLA2 activity in sperm sonicates. Furthermore, parallel experiments showed that exocytosis was enhanced if spermatozoa were treated with A23187/Ca2+ and either OAG or 1-O-C16/2-C2. Since both diacyl- and alkylacylglycerols increased PLA2 activity and exocytosis, stimulation of PLA2 activity by these diglycerides may take place independently from protein kinase C activation.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP65914843 1-Stearoyl-2-arachidonoyl-sn-glycerol 1-Stearoyl-2-arachidonoyl-sn-glycerol 65914-84-3 Price
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