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: Increases of MAP occurred after LV administration of 1 , 10 and 50 ng of AVP in WKY and of 10 and 50 ng in SHR .
### Output Text:
Increases of MAP occurred after LV administration of 1 , 10 and 50 ng of <span class="chemical">AVP</span> in WKY and of 10 and 50 ng in SHR . 