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: Glucocorticoid - induced hypertension ( GC - HT ) in the rat is associated with nitric oxide - redox imbalance .
### Output Text:
Glucocorticoid - induced hypertension ( GC - HT ) in the rat is associated with <span class="chemical">nitric oxide</span> - redox imbalance . 