The main pathways of hydrolysis and synthesis of phosphoinositides, me
tabolism of inositol phosphates and their role in animal and human cel
ls are reviewed, Mechanisms of regulation of phospholipase C and other
key enzymes of phosphoinositide metabolism by hormones and growth fac
tors are discussed. The mechanisms of regulation of metabolism and cel
lular activity by second messengers formed during activation of phosph
oinositide hydrolysis are considered. Special attention is given to th
e regulation of cytoplasmic Ca2+ level by inositol phosphates. The rev
iew summarizes data on formation and possible biological role of inosi
tol phosphates and phosphoinositides containing phosphate at position
3. The role of phosphoinositides in the interaction of cellular membra
nes with proteins of the cytoskeleton is considered.