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: The subcutaneous injection of isoproterenol ( 30 mg / kg ) into rats twice at an interval of 24 h , for two consecutive days , led to a significant increase in serum lactate dehydrogenase , creatine phosphokinase , alanine transaminase , aspartate transaminase , and angiotensin - converting enzyme activities , total cholesterol , triglycerides , free serum fatty acid , cardiac tissue malondialdehyde ( MDA ) , and nitric oxide levels and a significant decrease in levels of glutathione and superoxide dismutase in cardiac tissue as compared to the normal control group ( P < 0 . 05 ) .
### Output Text:
The subcutaneous injection of <span class="chemical">isoproterenol</span> ( 30 mg / kg ) into rats twice at an interval of 24 h , for two consecutive days , led to a significant increase in serum <span class="chemical">lactate</span> dehydrogenase , <span class="chemical">creatine</span> phosphokinase , <span class="chemical">alanine</span> transaminase , <span class="chemical">aspartate</span> transaminase , and <span class="chemical">angiotensin</span> - converting enzyme activities , total <span class="chemical">cholesterol</span> , <span class="chemical">triglycerides</span> , free serum <span class="chemical">fatty acid</span> , cardiac tissue <span class="chemical">malondialdehyde</span> ( <span class="chemical">MDA</span> ) , and <span class="chemical">nitric oxide</span> levels and a significant decrease in levels of <span class="chemical">glutathione</span> and <span class="chemical">superoxide</span> dismutase in cardiac tissue as compared to the normal control group ( P < 0 . 05 ) . 