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: The acute effect of insulin treatment on the earlier reported protective effect of streptozotocin diabetes against the cardiotoxic effect of high doses of isoproterenol ( ISO ) was investigated in rats .
### Output Text:
The acute effect of insulin treatment on the earlier reported protective effect of <span class="chemical">streptozotocin</span> diabetes against the cardiotoxic effect of high doses of <span class="chemical">isoproterenol</span> ( <span class="chemical">ISO</span> ) was investigated in rats . 