Sex Changing, Hormones, Fish Brains And The Usual Stuff

I was finally able to use some of my own current research in a lecture yesterday, showing my annotated digital image of a dorsal view of a scarlet shiner brain. This was in my Vertebrate Reproduction class and we're talking about different forms of sex determination in fishes, variously genetic, behavioral and temperature. Any internal signalling system has to go through the brain, of course, so it makes sense to look at a typical fish brain and point out where important features likes the hypothalamus and preoptic area reside. I also had a chance to mention one of my favorite bands from the late '70s, Root Boy Slim and the Sex Change Band, but that was a serious digression.

The good thing about doing this class is my realization that for our research on male scarlet shiner coloration and differentiation we should look at 11-ketotestosterone (11-KT) levels as the key androgen shaping secondary sexual characteristics. I had been thinking that the more common form of testosterone would be OK, but 11-KT is more potent for sexual activity in male fishes. It's more difficult to assay blood plasma levels, probably existing at about 15 picograms per microliter, but Jennifer says that she feels confident to do it so we will. The ELISA test kit for this costs 'bout $240 so that's what I'll request from the department.