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: Blood pressure and volume states as assessed by bodyweight , plasma renin and noradrenaline ( norepinephrine ) concentrations were similar on the 2 regimens .
### Output Text:
Blood pressure and volume states as assessed by bodyweight , plasma renin and <span class="chemical">noradrenaline</span> ( <span class="chemical">norepinephrine</span> ) concentrations were similar on the 2 regimens . 