[Effect of estradiol on the rat brain synaptosomal phosphoinositide composition]

The in vivo action of estradiol was shown to cause changes both in the total amount of phosphoinsitides and their individual fractions of rat synaptosomes. The maximum elevated levels of phosphoinositides was revealed on 1-hour exposure to the hormone. It is suggested the redistribution of phosphoinositides at the primary stage (1 hour postinjection) of exposure may rely on the initiation and functioning of the phosphoinositide mechanism, the ratio of triphosphoinositide to monophosphoinositide may be a peculiar indicator of the status of synaptosomal membranes for the functioning of this regulatory system.