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: Offspring of rats administered dexamethasone on days 15 and 16 gestation had a 20 % reduction in glomerular number compared with control at 6 to 9 months of age ( 22 527 + / - 509 versus 28 050 + / - 561 , P < 0 . 05 ) , which was comparable to the percent reduction in glomeruli measured at 3 weeks of age .
### Output Text:
Offspring of rats administered <span class="chemical">dexamethasone</span> on days 15 and 16 gestation had a 20 % reduction in glomerular number compared with control at 6 to 9 months of age ( 22 527 + / - 509 versus 28 050 + / - 561 , P < 0 . 05 ) , which was comparable to the percent reduction in glomeruli measured at 3 weeks of age . 