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 findings support the reports concerning digoxin effect on plasma estradiol , testosterone , and LH .
### Output Text:
The findings support the reports concerning <span class="chemical">digoxin</span> effect on plasma <span class="chemical">estradiol</span> , <span class="chemical">testosterone</span> , and LH . 