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: CONCLUSION : Testosterone administration ameliorates STZ - and castration - induced memory impairment in male Wistar rats .
### Output Text:
CONCLUSION : <span class="chemical">Testosterone</span> administration ameliorates <span class="chemical">STZ</span> - and castration - induced memory impairment in male Wistar rats . 