progesterone or cortisol?

[Dr.Stein]

I have some plasma sample left after a research. It was for investigating testosterone production after administration by a substance which is believed contains aphrodisiac substance. I want to use those serum for something else, which is still related to the previous research. My candidates are measuring level of progesterone or cortisol. Unfortunately, I don't have enough money to run them simultaneously. Thus, I need to make priority, which one I should run first. Maybe you could give me some advices. Thank you

[Darby]

This is probably not a useful suggestion, but for a possible aphrodisiac, I'd look for epinephrine. Sexual excitement is still excitement...

[victor]

I can suggest that run the progesterone investigation first :p
well, I think that aphrodisiac substances would not influence cortisol improvement as fast as it influences progesterone improvement. So I'm afraid that if you run cortisol first, you'll get an unsignificant result for it

[Dr.Stein]

First, thank you to Dr.Darby and Victor for the reply.

@Dr.Darby: As my sample is old and epinephrine is a protein, I am afraid the assay wouldn't valid. What do you think?

@Victor: Progesterone is precursor of testosterone, so literally, the level of progesterone would be in similar pattern to the level of testosterone, IMO. About cortisol, there IS a closed relationship, because my subject was male mice, and during the experiment (2-3 months) we didn't provide female mice, also high testosterone level initiated aggressiveness and fight action in mice life. Indeed, this is a potential stressor which related to cortisol secretion. However, progesterone assay would be nice to support my primary data. Here I am confused..

[Darby]

Yeah, I was wondering if breakdown would be an issue.

The cortisol might be interesting, but the connection to what you're interested in is an awfully indirect one.

[Dr.Stein]

Indirect? But my co-supervisor asked me to think about it? Stress as effect from aphrodisiac/high testosterone level...

[sdekivit]

all steroid hormones are produced from cholesterol --> this will result in progesteron synthesis. Cortisol is a downstream product of progesterone after several enzymatic modifications.

it depends on the study question you want to answer: if it's the direct effect of high testosterone level on cortisol production i would suggest to measure cortisol.

but: other mechanisms could also play a role, so measuring progesterone is also interesting as cortisol can be produced from progesterone.

[Dr.Stein]

That's my confusion. I will do both by I asked about priority due to my finance situation.

@sdekivit:
What do you think of testosterone-cortisol relationship in my case? So far I come up with hypothesis that high level testosterone will affect the secretion of cortisol. The reason is that my mice got stressed after aphrodisiac administration, which related to their libido and aggresiveness for social hierarchy among them. I need more references for this.

[victor]

umm....I think I know a good book for it. Just look for a book titled GENOM (indonesian version) by Matt Ridley, published by Gramediain our library (Library of Biology faculty, UGM). I ever saw it there. Just read chapter 8-10 and maybe you can find your answer there.

[Dr.Stein]

A textbook? My references are journals

[victor]

some kinda like a novel