Posted by Tomatheus on January 16, 2007, at 20:04:58
In reply to Re: How to increase monoamine oxidase (?), posted by linkadge on January 15, 2007, at 9:04:50
> Or perhaps something pro-progesterone?
>
> I heard progesterone increase MAO. Not sure though.Unfortunately, I haven't researched the relationship between progesterone and MAO acvitity thoroughly enough to say with any measure of confidence what effect an increase in progesterone levels would have on human MAO acvitity.
Judging from my reading of the Gundlah et al. (2002) article that I cited in my previous post to this thread, the evidence pertaining to progesterone's regulatory actions on MAO activity seems to be somewhat contradictory. It may be the case that such regulatory actions vary from one species to the next, but I haven't come across enough evidence to say for certain whether or not this is the case.
At any rate, here are a few facts from the Gundlah et al. (2002) article on the relationship between progesterone levels and MAO activity:
* Previous studies had shown that the acute administration of estrogen reduced hypothalamic MAO-A activity in rats. Subsequent administration of progesterone to estrogen-primed rats was found to restore hypothalamic MAO-A activity. (This would support the idea that progesterone would increase MAO activity, at least in rats).
* Gundlah et al. (2002) wrote that "the actions of [estrogen] and [progesterone] in the serotonin system differ in various respects between rodents and primates." The researchers, however, did not make any specific references to previous research findings that would support the idea that progesterone affects the rodent serotonin system any differently than it affects the primate serotonin system.
* The results of the study carried out by Gundlah et al. (2002) indicate that progesterone, like estrogen, reduces the optical density of MAO-A mRNA in the dorsal raphe nucleus and in the hypothalamic paraventricular nucleus, lateral hypothalamus, and ventromedial nucleus of spayed rhesus monkeys. The study's authors also pointed out that neither estrogen nor progesterone affected the expression of MAO-B mRNA in the dorsal raphe nucleus, but both ovarian hormones significantly reduced the optical density of MAO-B in the hypothalamic preoptic area, lateral hypothalamus, and ventromedial nucleus of the primates that were studied. (So, these findings would support the idea that progesterone might actually *reduce* MAO activity -- instead of increasing it -- in humans. Of course, that's assuming that progesterone's regulatory actions on MAO activity in humans are the same as they are in rhesus monkeys ).
That basically sums up the facts that I've come across concerning the relationship between progesterone and MAO activity. As you can tell, the evidence seems to be somewhat contradictory, possibly due to inter-species differences in progesterone's regulatory actions on MAO activity.
I'm not sure that this helps, other than to show that progesterone's regulatory actions on MAO activity in humans are at least somewhat uncertain. Then again, maybe a study has been done since the Gundlah et al. (2002) report was published to help clear up some of these uncertainties. I am not aware of any such study having been done, though.
Tomatheus
==
REFERENCE
Gundlah, C., Lu, N. Z., & Bethea, C. L. (2002). Ovarian steroid regulation of monoamine oxidase-A and B mRNAs in the macaque dorsal raphe and hypothalamic nuclei. Psychopharmacology, 160, 271-282.
poster:Tomatheus
thread:721832
URL: http://www.dr-bob.org/babble/alter/20070114/msgs/723013.html