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: In normal rats with intact kidneys , rhIGF - I administration ( n = 4 ) did not alter weight gain , blood pressure , proteinuria , GFR , glomerular planar area , renal cortical malondialdehyde content , or glomerular or tubulointerstitial damage , compared with untreated animals ( n = 4 ) .
### Output Text:
In normal rats with intact kidneys , rhIGF - I administration ( n = 4 ) did not alter weight gain , blood pressure , proteinuria , GFR , glomerular planar area , renal cortical <span class="chemical">malondialdehyde</span> content , or glomerular or tubulointerstitial damage , compared with untreated animals ( n = 4 ) . 