I already get liver enzymes tested for the medication I take with my colitis. I get tests every 3 months (or at least I'm supposed to). Is there anything else I should get tested for while on something like cyproterone? For example, blood sugar and testosterone levels?

Testosterone levels, for sure. Also do a haemoglobin test, maybe once a year. I developed anemia after a year or so on Androcur.

Also keep in mind that low testosterone can lead to osteopina/ostoeporosis. After a couple years, you might want a bone density exam. Or at least take some supplemental calcium with vitamin D to minimize that risk. I take additional calcium as well as iron for the reason hkeunuch posted above. I give blood regularly and after I was castrated was refused because hemoglobin was low. Taking iron brought me back up to snuff.