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: Chronic CYP administration significantly ( P < or = . 002 ) increased bladder weight by 60 % and increased ( 7 - to 11 - fold ) the numbers of NOS - immunoreactive ( IR ) afferent neurons in the L6 - S1 DRG .
### Output Text:
Chronic <span class="chemical">CYP</span> administration significantly ( P < or = . 002 ) increased bladder weight by 60 % and increased ( 7 - to 11 - fold ) the numbers of NOS - immunoreactive ( IR ) afferent neurons in the L6 - S1 DRG . 