Plasma adenomedullin, calcitonin gene-related peptide and c-type natriuretic peptide in rats with hypoxic pulmonary hypertension

Objective To explore the effects of hypoxia on the syntheses and secretion of adrenomedullin (AM), calcitonin gene related peptide (CGRP) and c type natriuretic peptide (CNP) and the relationship between these peptides. Methods Rat models were established with hypoxia for 10, 20 and 30 d respectively and rats under normal altitude were served as control. Pulmonary artery pressure and the maximum increasing speed of right ventricle (RVdp/dt max ) were measured in every group. The dynamic changes of AM, CGRP and CNP concentrations in plasma were studied with radioimmunoassay. Results During hypoxia, pulmonary artery pressure and RVdp/dt max were enhanced. Plasma AM and CNP concentrations were increased while CGRP was decreased significantly. The plasma level of AM had positive correlation with that of CNP, but negatively correlated with that of CGRP. Conclusion Results indicate that hypoxia may cause pulmonary artery pressure change and right ventricle has compensatory reaction to hypoxic pulmonary hypertension. Dynamic changes of plasma AM, CGRP and CNP concentrations can be regarded as indexes for condition of illness.