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: Adrenaline , but not noradrenaline , caused a delayed and protracted pressor effect .
### Output Text:
<span class="chemical">Adrenaline</span> , but not <span class="chemical">noradrenaline</span> , caused a delayed and protracted pressor effect . 