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: CONCLUSIONS : In contrast to the adult , fluoxetine exposure in utero induces pulmonary hypertension in the fetal rat as a result of a developmentally regulated increase in pulmonary vascular smooth muscle proliferation .
### Output Text:
CONCLUSIONS : In contrast to the adult , <span class="chemical">fluoxetine</span> exposure in utero induces pulmonary hypertension in the fetal rat as a result of a developmentally regulated increase in pulmonary vascular smooth muscle proliferation . 