Angiotensinogen metabolism in rat aorta: robust formation of proangiotensin-12

Renin-angiotensin system (RAS) plays important role in the regulation of vessel wall homeostasis. Proangiotensin-12 (proAng-12, Ang-(1-12)) is a newly characterized metabolite of angiotensinogen, formed in array of organs of rats, which may serve as an alternate substrate for local angiotensin production, by-passing the traditional renin-dependent conversion of angiotensinogen to angiotensin I. In this work using LC/MS method we identified proAng-12 as a main product of angiotensinogen metabolism ex vivo, in organ-bath of rat aortic tissue. In this setting, proAng-12 appeared to be not only prevalent metabolite of angiotensinogen, but also served as a substrate for generation of Ang I and subsequently, Ang II. The functional significance of this surprising finding requires further investigation.

[Diagnostic value of mucin-like associated antigen (MCA) in neoplasms of the mammary gland]

The aim of the present study was to evaluate the diagnostic value of the new tumour marker MCA in serum from women with breast cancer. Relationship between presence MCA in serum and cER, cPgR, nER, nPgR in aqueous extracts from cancer tissues was subject of our investigation, too. Immunoenzymatic method (Roche) which employed monoclonal antibody MAb b-12 was used for determination of MCA in serum 49 operable patients (preoperative determination). In a group of 26 cancer patients MCA and cER, cPgR, nER, nPgR were tested simultaneously. Steroid hormone receptors were measured by immunoenzymatic method (Abbott). Mean concentration of MCA in women with breast cancer (n = 36) was higher as compared with control (n = 21, p < 0.001). When 6.86 U/ml was took as mean level of MCA in control group it was found that 46% women with benign tumours, 64% with carcinoma ductal and 62% with carcinoma lobular have had concentrations of MCA below this value. Also it was found that differences between mean levels of MCA and cER, cPgR, nER, nPgR were statistical significance only in women with carcinoma ductal. On the basis of our own investigations we can suggest that MCA has limited value in the diagnosis of breast cancer.