Bile acids, in particular chenodeoxycholic acid (CDCA) and cholic acid (CA), can regulate the expression of genes involved in their synthesis, thereby, creating a feed-back loop. The elucidation of this regulatory pathway came about as a consequence of the isolation of a class of receptors called the farnesoid X receptors, FXRs . The FXRs belong to the superfamily of nuclear receptors that includes the steroid/thyroid hormone receptor family as well as the liver X receptors (LXRs) , retinoid X receptors (RXRs), and the peroxisome proliferator-activated receptors (PPARs) .
How might behaviors affect hormones? The birdsong example demonstrates how hormones can affect behavior, but as noted, the reciprocal relation also occurs; that is, behavior can affect hormone concentrations. For example, the sight of a territorial intruder may elevate blood testosterone concentrations in resident male birds and thereby stimulate singing or fighting behavior. Similarly, male mice or rhesus monkeys that lose a fight decrease circulating testosterone concentrations for several days or even weeks afterward. Comparable results have also been reported in humans. Testosterone concentrations are affected not only in humans involved in physical combat, but also in those involved in simulated battles. For example, testosterone concentrations were elevated in winners and reduced in losers of regional chess tournaments.
Congratulate you and your whole team on the grand success of the Conference held in Philadelphia, USA. It was well planned and organized. Since all members of the managing committee were very friendly and sincere we felt homely at all moments. Moreover, my especial thanks are due to you and your team for the kind cooperation, hospitality and management. I look forward and wish you the best for the next meeting to be held in 2016. Once again, I thank you and all the crew members associated with the 4th International Conference and Exhibition on Metabolomics & Systems Biology. With my sincere regards and best wishes, to you and your team.