Angiotensins II and IV stimulate the activity of tyrosine kinases in estrogen-induced rat pituitary tumors.
The effects of angiotensin II (AngII) and its fragment 3-8 (angiotensin IV, AngIV) on tyrosine kinase (TK) activity in estrogen-induced rat pituitary tumor homogenates were studied. It was found that both angiotensin peptides increase the TK activity. AngIV was effective in a lower concentration and its maximal effect was greater as compared to that of AngII. Moreover, the specific inhibitors of aminopeptidase A (EC33) and of aminopeptidase N (PC18) significantly attenuated the stimulatory effect of AngII. Because the action of both aminopeptidases is necessary to convert AngII into AngIV, this finding suggested that the effect of AngII on TK activity is (at least in part) exerted via AngIV.
D000626:Aminopeptidases / Q000037:antagonists & inhibitors; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D004054:Diethylstilbestrol; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D043384:Glutamyl Aminopeptidase; D010911:Pituitary Neoplasms / Q000139:chemically induced / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats
D004791:Enzyme Inhibitors; D000804:Angiotensin II; C012877:angiotensin II, des-Asp(1)-des-Arg(2)-Ile(5)-; D004054:Diethylstilbestrol; D011505:Protein-Tyrosine Kinases; D000626:Aminopeptidases; D043384:Glutamyl Aminopeptidase