Phosphoinositide phosphorylation precedes growth in rat mammary tumors

Yoav Sharoni, Iris Teuerstein, Joseph Levy

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


DMBA-induced rat mammary tumors were used to study the possible association of phosphoinositide phosphorylation to tumor growth. These membranous enzymatic activities were measured during various stages of tumor growth induced by pharmacological manipulation of plasma prolactin level. An increase in phosphorylation of both phosphatidyl inositol and phosphatidyl inositol 4-phosphate preceded the growth induced by prolactin concomitantly with an increase in tyrosine phosphorylation. Good correlation (r=0.87) existed between the tyrosine kinase activity and phosphatidyl inositol kinase activity of 21 individual tumors taken from animals at different stages of hormonal manipulation. Phosphoinositide phosphorylation was inhibited by quercetin and was not affected by cAMP, similar to tyrosine kinase. Phosphorylation of angiotensin II by tyrosine kinase was inhibited by 0.2 mg/ml phosphatidyl inositol 4 phosphate or phosphatidyl inositol 4,5-bisphosphate.

Original languageEnglish
Pages (from-to)876-882
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - 29 Jan 1986


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