Titel

Die Wirkung von Aldosteron auf die Proteinbiosynthese am kultivierten Sammelrohrepithel der Kanincheniere

Titel(englisch)

Action of aldosterone on protein svnthesis on cultured collective duct epithelium from rabbit kidneys

Name:

Zwanzig, Marianne

Ort und Jahr der Promotion

Berlin, Freie Univ., Diss., 1990

Abstract

The action of aldosterone on protein synthesis in correlation to the physiological hormone effects was investigated in a renal collecting duct cell cuture model from neonatal rabbit kidneys.It could be determined that aldosterone increased the intracellular radioactive uridine and amino acid pool and furthermore the total radioactive RNA and protein content already during the latent period. These results indicate that aldosterone enhanced the uptake of RNA and protein precursors into the cells and the new synthesis of RNA and proteins. These events seems to be regulated not continuously but intermittently. The induced proteins presumably take part in the mediation of the early hormone response, while the bulk of the induced RNA is used for translation of AIPs possibly first during he late response.Additionally, increased new synthesized protein was found during the early as well as during the late physiological hormone response with a maximum after 7 hours and hence in correlation to the late hormone response. These AIPs are not only found after aldosterone application but also in controls. Therefore, these proteins are not classical AIPs but increased synthesized AIPs which occur also under control conditions but in a lower degree.Experiments with the aldosterone antagonist spironolactone provide evidence for the specifity of the described hormone effects. The results after application of the Na+ channel blocker amiloride and the Na/K ATPase inhibitor g-strophantin indicate that the aldosterone effects are controlled by Na+ channels and Na+ pumps and therefore by he intracellular Na+ content. The inhibitory effect of the protein synthesis inhibitor cycloheximide on the AIPs indicates the role of these proteins on the hormone stimulated Na+ transport.