Cugini P, Letizia C, Lucia P, Di Palma L, Scavo D
I Patologia Medica, Università di Roma La Sapienza, Italia.
Enzyme. 1989;41(2):94-100. doi: 10.1159/000469059.
An increase in morning fasting levels of plasma (P) renin activity (RA), aldosterone (A) and serum (S) angiotensin-converting enzyme (ACE) activity has been demonstrated in ascitic cirrhotic patients (ACP). Since both PRA and PA change biorhythmically in their time structure, the relationship of SACE activity with the components of the renin-angiotensin-aldosterone system (RAAS) was investigated in clinically healthy subjects (CHS) and ACP. Time-qualified data were chronobiologically analysed by means of the cosinor procedure to resolve and quantify the circadian rhythm (CR). The 24-hour mean levels of PRA, PA and SACE activity were found to be elevated in ACP as compared to CHS. The temporal variability of these analytes was found to be of periodic type along the 24-hour span in CHS, but not in ACP. The well-organized cyclicity in CHS is of relevant interest. PRA and PA cycles were found to phase in a clear antiparallelism with the SACE activity CR. The phase opposition may be, speculatively, related to the physiologic nature of ACE, whose activity is devoted to generate angiotensin II. The disappearance of SACE activity CR in ACP is in accordance with the abolition of PRA and PA cyclicity and suggests a role of liver in regulating the periodic time function of the RAAS and related components.
