Interesting read

[EdMan2]

Hopefully this isn't a redundant post, but just out of curiosity I was looking around to see why strong aromatase inhibitors , such as letro, kill sex drive. I didn't know why estrogen would be needed in males to control sex drive. I ran across this primary research article published in 2004 using ArKO male mice (aromatase knockout mice: basically these mice produce zero aromatase enzyme). I'll just post the abstract instead of typing the whole thing out, it'll explain things better.

"The aromatase knockout (ArKO)next term mouse is unable to synthesize estrogens. Immunohistochemical studies on active caspase-3 and tyrosine hydroxylase (TH) revealed apoptosis of dopaminergic neurons in the medial preoptic area (MPO) and arcuate nucleus (Arc) of the hypothalamus of 1-year-old (1yo) male previous termArKOnext term mice while no active caspase-3 was detected in wild type (WT). Furthermore, the number of TH-positive cells in the MPO and caudal Arc was significantly decreased in 1yo previous termArKOnext term compared to WT. RNase protection assays support the presence of apoptosis in 1yo previous termArKOnext term hypothalamus, reve****g an up-regulation of pro-apoptotic genes: FASL, FADD, and caspase-8. Concomitantly, the ratio of bcl-2-related anti-apoptotic genes to pro-apoptotic genes in the hypothalamus of 1yo previous termArKOnext term mice was significantly down-regulated. Previously, we have reported that no such changes were observed in the hypothalamus of female previous termArKOnext term mice. Thus, we have provided direct evidence that estrogen is required to maintain the survival and functional integrity of dopaminergic neurons in the MPO and Arc of male, but not female mice."


In the discussion they state that:

"Release of dopamine in the medial preoptic area of the hypothalamus is believed to positively regulate the anticipatory/motivational phase of copulatory behavior (Giuliano and Allard, 2001). Several reports have identified dopamine as an important transmitter of the control of male sexual behavior (Bitran and Hull, 1987, Blackburn et al., 1992 and Hull et al., 1995). Indeed, our laboratory has previously demonstrated that the male ArKO has a severe disruption in sexual behavior, displaying increased latency to mount females, increased time to initiate mounts, and increased time between mounts compared to WT (Robertson et al., 2001). We propose that the decrease in the levels of presynaptic vesicles, and hence lowered activity, observed in the MPO of the mature ArKO (Fig. 5A) may account for the disruption of sexual behavior of young male ArKO mice and by 1 year of age the loss of dopaminergic neurons via apoptosis in the MPO may contribute to the severe disruption in sexual behavior of the older animals."

These findings show the reasons why taking things such as letro or a-dex negatively affect the male sex drive, or at least one aspect. The full paper can be found here: http://www.sciencedirect.com/science.../sdarticle.pdf

[EdMan2]

Bump, anyone read this? No opinions?