Wednesday, March 2, 2016

Estrogen and Serotonin Connection : Implications for Male Libido Explored

Estrogen is an important hormone in both man and woman, it also plays a rather large role in sexual desire, in part, through it's mediations and intertanglement with the serotonergic system.

It is so commonly claimed that by ''crushing'' one's E2 (estradiol,estrogen) level that they experience a loss of sex drive and / or erectile problems - while others (relatively very few) experience no such effect - but their joints may ache.

By these reports and a few Clinically insignificant 'studies' on RATS - it has been claimed that this is a quick jot of information that can be used as a fail-safe reference for bodybuilders and powerlifters alike.

It can be claimed that a certain amount of Estrogen is 'necessary' or 'needed' for the male libido. It can be seen that both high and low estrogen result in the same unsavory consequences...

Yet, the whole picture is not so simple.

ONE BIG QUESTION I have been asked is :

"If ESTROGEN Supports Serotonin Production then Obliterating Estrogen Should Remove Serotonin and then Cause High Libido, but it is the opposite, Why?"

This is based off of the well-known fact that serotonin dampens the male libido (and anyones libido, for that matter) - the issue with this type of thinking is the linearity is actually stupidity. 

YES, estrogen , technically ''supports'' Serotonin Production; including in the Brain. However, when you diminish Estrogen - you also diminish other neurotransmitters and some neuropeptides, so even though you are closing-out Serotonin (5-HT) - you are also doing nearly the same to dopamine and glutamate ; two important neurotransmitters for libido/arousal.

The OTHER ISSUE is making the assumption that by lowering Estrogen will AUTOMATICALLY decrease Serotonin - Sure, it may decrease it, but that doesn't mean it's GONE or MINIMIZED, by any means. There are still other factors/hormones that can increase / stimulate Serotonin production in the absence of  Estrogen (like Vitamin D, Magnesium, Progesterone etc) - thus, it does not guarantee a new 'favorable' balance by lowering Estrogen levels.

The other reason why lowering estrogen to near undetectable levels doesn't pan out, neurochemically, except on paper - is because there are some maverick differences between man and rat in terms of specific proportional effects of Estrogen on nNOS-immunostaining (a fancy way of saying that Estrogen affects nitric oxide enzymes a little differently or to a different degree between man and rodent).

In those that receive no libido-benefit from Estrogen-blockade, it can be seen that either.

A.) Estrogen was not the Problem.
B.) The NET level of dopamine is already decreased while the NET serotonin level is increased and / or the glutamate:GABA ratio is off in said-subject.


So dropping Estrogen levels may decrease the Serotonin level , but in cases where ones own Dopamine levels are not sufficient to balance the new drop, the result is no real benefit or a reduction in libido. The big pondering is the 'WHY' do some men born WITHOUT any ESTROGEN AT ALL, have perfect or 'normal' libidos/sex drive.

The answer is most likely that these men, alike to those who use high-dose aromatase inhibitors , are unsusceptible to estrogen-deprivation's adverse consequences which may be due to a high-normal or abnormally high level of dopamine and / or histamine or glutamate which compensates for the reduction of these neurons during Estrogen-deficiency. 

Another explanation is the aromatase-inhibition associated with sexual effects is not the actual issue but rather, the reduction in sex drive associated with aromatase inhibitors; e.g letrozole, arimidex etc may be due to OTHER ACTIONS of the drugs such as pharmacokinetic specs like CYP-pocc/CYP-occupation or inhibition of other steroid-related enzymes like 5-alpha-reductase.

Thus, even though, Estrogen relates back to the Serotonin-ergic pathways, it does not in any way guarantee the resolve expected in terms of the sexual desire pathway by means of serotonin-influencing actions ALONE.
Estrogen functionally integrates into the pathways/systems of neuropeptides such as Oxytocin/Vasopressin etc - and thus, E2 is likely promoting nitric oxide activity through one or both of these pathways.

So, IS ESTROGEN-REQUIRED FOR MALE SEXUAL FUNCTION/LIBIDO?

NO. However, despite serotonin/serotoninergic/serotonergic Pathways being decreased by lessened Estrogen - the net result is not favorable on the OTHER pathways - and PLUS, other mechanisms can be used by the body to re-ignite  Serotonin (5-HT) Production when Estrogen is very Low or even completely Absent in the Body. 

Given the control mechanisms of dopamine and glutamate in regards to Serotonin-release/projections - the result of lowering Estrogen is a mild anti-serotonergic effect but not enough to out-Do the dopamine/glutamate lowering effects of Estradiol and CERTAINLY not enough to completely diminish the serotonergic-neuronal system/s.

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