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: Sulpiride induced only SOCS - 1 in the medial preoptic area , where GnRH neurons are regulated , but in the arcuate nucleus and choroid plexus , PRL - R , SOCS - 3 , and CIS mRNA levels were also induced .
### Output Text:
<span class="chemical">Sulpiride</span> induced only SOCS - 1 in the medial preoptic area , where GnRH neurons are regulated , but in the arcuate nucleus and choroid plexus , PRL - R , SOCS - 3 , and CIS mRNA levels were also induced . 