just saw this.. I am definately a nay-sayer for using HCG as a PCT. It does nothing to modulate secretion from the pituitary.
as for ^^ the post above..
"Ligand-induced down-regulation of testicular and ovarian luteinizing hormone (LH) receptors is preceded by tissue-specific inhibition of alternatively processed LH receptor transcripts."
Ligand-induced down-regulation of testicular ... [Mol Endocrinol. 1991] - PubMed - NCBI
"Evidence that human chorionic gonadotropin/luteinizing hormone receptor down-regulation involves decreased levels of receptor messenger ribonucleic acid"
Evidence that human chorionic gonadotropin/lut... [Endocrinology. 1991] - PubMed - NCBI
^ granted yes, its not in a male.. but we have the same set of genes, just some get activated and some dont.. and I wouldnt think that estrogen modulated histone regulation for gene expression would have a large effect on the receptor in the cell.
"LH action in the Leydig cell: modulation by angiotensin II and corticotropin releasing hormone, and regulation of P450(17) alpha mRNA."
LH action in the Leydig cell: modulation b... [J Steroid Biochem. 1989] - PubMed - NCBI
^ This makes me lean toward the fact that HCG is known to increase estrogen in the testes, and that may be the reason for desensitization that occurs following high doses
"Modulation of Leydig Cell Androgen Biosynthesis and Cytochrome P-450 Levels during Estrogen Treatment and Human Chorionic Gonadotropin-induced Desensitization"
Modulation of Leydig cell androgen biosynthesis and cytochrome P-450 levels during estrogen treatment and human chorionic gonadotropin-induced desensitization.
I cant find any research on bio-active LH levels and how they respond with the addition of HCG, however i have found some that describe this with high doses, long term use of clomid. That the more LH is in the system, the more bio-inactive LH is produced which is "shootin blanks" b/c it doesnt react at the receptor level to initiate secretion however it does play a part in the feedback loop where the body senses that there is enough LH in the system.
As you can see, there are many studes out there that back up the claim of desensitization, and for the users here that are already having supraphysiological levels of test and estrogen; I definately lean towards that desensitization is definately a possibility and has a much greater chance to occur in this setting than a non-AAS user.