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 metabolic responses to isoprenaline in dogs ( an increase in circulating glucose , lactate and free fatty acids ) were all blocked by ( - ) - propranolol .
### Output Text:
The metabolic responses to <span class="chemical">isoprenaline</span> in dogs ( an increase in circulating <span class="chemical">glucose</span> , <span class="chemical">lactate</span> and free <span class="chemical">fatty acids</span> ) were all blocked by ( - ) - <span class="chemical">propranolol</span> . 