ALTERATION OF RAT MYOCARDIAL PEPTIDE HORMONES WITH INCREASING AGE / 中华内分泌代谢杂志

ABSTRACT

The process of aging can induce major alterations in structure and function of myocardium. 41 female Wistar rats-weighing 50-586 g were divided into 5 groups (1,3, 6,10, 21 mo.). The 21-month group was taken as aged rats. Myo-cardial homogenates (W/V= 1 g/10 ml) were prepared. The local myocardial immunoreactive Ang I, II and the ventricular ANF levels in different parts of the myocardium were measured by sensitive RIA. The sections of the myocardial tissue were prepared. The local Ang II and ANF were measured by immunohistochemistry. The results showed that auricular Ang II and ANF is markedly higher than the ventricular ones. Local myocardial Ang II is for the most part present in the cytoplasm. There is a positive correlation between the local Ang I and Ang II levels. There are significant differences in levels of Ang I, Ang II and interventricular septum ANF between various age groups. There is a perfect negait ve correlation between levels of Ang as well as ANF and the age in months. The reduction in local Ang II level is most striking in the 21-month group. The reduction of local Ang II level in the ventricles exceeds that in the atria. The experiment suggested that as age increases, some important hormonal functions of the heart gradually weaken; such a change is most noticeable in the ventricles.