In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: In conclusion , ENaC mRNA expression , especially alphaENaC , is increased in the very early phase of the experimental model of PAN - induced nephrotic syndrome in rats , but appears to escape from the regulation by aldosterone after day 3 .
### Output Text:
In conclusion , ENaC mRNA expression , especially alphaENaC , is increased in the very early phase of the experimental model of <span class="chemical">PAN</span> - induced nephrotic syndrome in rats , but appears to escape from the regulation by <span class="chemical">aldosterone</span> after day 3 . 