[Lotus]

It also down regulates DHT through 5 alpha reductase.

Regulation or (de)sensitization happens to receptors, not hormones AFAIK. Did you mean something else?

Nope, I didn't mean something else, the info below explains regulation.

Plasma levels of sex-hormone-binding globulin (SHBG) in man are known to be regulated up and down by oestradiol and testosterone.
http://www.ncbi.nlm.nih.gov/pubmed/2591057

DHEA upregulates the activity of 5AR (5-alpha-reductase) enzyme, which further converts testosterone to DHT. As a consequence, some women may experience a slight increase in hair loss, especially if their estrogen levels are low.
@ MedLine Plus

Hormonal regulation of hormone release involves a hormone binding to its receptor on an endocrine cell to regulate hormonal secretion. A hormone that stimulates hormone secretion is called a tropic hormone. Tropic hormones may also stimulate proliferation of endocrine cells.

The ACTH (adrenocorticotropic hormone (ACTH) receptor is a G-protein coupled receptor or seven-transmembrane domain protein. ACTH binding ultimately leads to stimulation of adenylyl cyclase and the production of the second messenger cyclic AMP (cAMP). cAMP causes cellular changes that ultimately lead to the activation of the enzymes involved in cortisol synthesis.

In some cases, hormones can inhibit hormone secretion. One key example is the peptide hormone somatostatin, which is a hypothalamic hormone that inhibits GH secretion. Another important example is negative feedback regulation in which hormones negatively regulate the secretion of their own tropic hormones.

http://courses.washington.edu/conj/bess/hormonal/hormonal.html

Why improving receptor sensitivity is important for NBE,


Regulation of hormone receptors is very important for a normal functioning cell. There are several ways a cell regulates its hormone receptors. Below is an outline of such regulatory functions

Regulating the expression of receptors - changing the number of receptors on the plasma membrane.
________________________________

1. Up regulation - increasing the number of receptors

2. Down regulation - decreasing the number of receptors

Mechanism:

-internalization - endocytosis of receptors

-modify transcription - inhibiting or stimulating transcription factors

-modify receptor half-life - adding groups to the receptors which will degrade them faster


Downregulation is the process by which a cell decreases the quantity of a cellular component, such as RNA or protein, in response to an external variable. An increase of a cellular component is called upregulation.

An example of downregulation is the cellular decrease in the number of receptors to a molecule, such as a hormone or neurotransmitter, which reduces the cell's sensitivity to the molecule. This phenomenon is an example of a locally acting negative feedback mechanism.

An example of upregulation is the increased number of cytochrome P450 enzymes in liver cells when xenobiotic molecules such as dioxin are administered (resulting in greater degradation of these molecules).

Most receptor agonists downregulate their respective receptor(s), while most receptor antagonists upregulate their respective receptor(s). The disequilibrium caused by these changes often causes withdrawal when the long-term use of a medication or drug is discontinued. However, the chronic use of certain receptor antagonists may also damage receptors faster than they upregulate.

Upregulation and downregulation can also happen as a response to toxins or hormones. An example of upregulation in pregnancy is hormones that cause cells in the uterus to become more sensitive to oxytocin.

An agonist is a chemical that binds to a receptor and activates the receptor to produce a biological response. Whereas an agonist causes an action, an antagonist blocks the action of the agonist and an inverse agonist causes an action opposite to that of the agonist.




Downregulation and upregulation

http://wikipedia.org/wiki/Downregulation_and_upregulation
Question- what triggers tissue growth in order for NBE to work?