The cortisol and sex hormone receptors, the nuclear receptors, are all related and all diversified (almost like species of animals) from the same gene that got duplicated by accident in some individual animal's genome. That happened dozens of millions of years ago, before there were humans, or even monkies. And accordingly, all the hormones that bind those receptors are variations on the cholesterol molecule, with a similar overall structure.
GH is a totally different bird, a giant hormone 20 or 30x the size of testosterone or cortisol. So it cant directly activate the cis-acting glucocorticoid response element in XMRV's genome. The thing to wonder about is whether GH could alter XMRV's behavior indirectly, by increasing the production of things like cortisol, or cortisol receptor, progesterone, progesterone receptor -- whatever.
Alesh I'm very interested in your comments & those of Eric Johnson re: growth hormone.
I believe that many of us respond poorly to growth hormone (& gh-releasing peptides), or at least I do. Both gh and gh-releasing peptides (e.g. ghrp-6) seem to markedly increase acth/cortisol for me. The peptides I can understand since they are non-specific to gh and are known to increase acth/cortisol. But synthetic gh itself also seems to have a marked cortisol reaction in me.
GH is supposed to increase delta/phase-4/restorative sleep. In me the cortisol spike dominates and my sleep is worsened. The effects of the increased cortisol lasts for a good few days.
I've heard 2 explanations for why GH may increase cortisol, neither of which may be true. The first is that if you have inadequate hormonal resources to carry out the repairs signalled by GH, the body will increase cortisol to try and block the repair messages. The second explanation is that cortisol is needed for GH to carry out its work, and that if you lack sufficient cortisol your body will make some. I don't know if either explanation is true, but the net result is that GH seems to increase cortisol in me.