In the rat-model based study, Schroeder developed an approach based on nuclear magnetic resonance (NMR) spectroscopy of partially purified urine. NMR spectroscopy is the most powerful tool chemists used to determine the structures of unknown compounds. It has only been used for the analysis of purified compounds.
In the study, the usage of the technique revealed three completely new compounds, each of which was subsequently synthesized and injected into rats. The rats' urine was then monitored. Two of the identified compounds, derivatives of a common metabolite xanthurenic-acid, raised sodium levels in the rat's urine but kept potassium levels constant.
Schroeder said that while aldosterone was a steroid hormone, the newly discovered molecule was structurally more similar to such amino acid-derived neurotransmitters as dopamine and serotonin and, therefore, might also play other roles in the body. "Now, we want to know what other functions these compounds have and whether they directly influence blood pressure," Schroeder said.
The study is published in Proceedings of the National Academy of Sciences.