ERα/ERβ are in inactive state trapped in multimolecular chaperone complexes organized around the heat shock protein 90 (HSP90), containing p23 protein, and immunophilin, and located in majority in cytoplasm and partially in nucleus. In the E2 classical pathway or estrogen classical pathway, estradiol enters the cytoplasm , where it interacts with ERs. Once bound E2, ERs dissociate from the molecular chaperone complexes and become competent to dimerize, migrate to nucleus, and to bind to specific DNA sequences ( estrogen response element , ERE), allowing for gene transcription which can take place over hours and days.

I am on fresh egg donor transfer cycle and I didnt have period for 4 months before the cycle. The doc put me on 75ml patches (every 72 hours) for 10 days, my lining has increased from (before patch) to 13mm and I still have to wait for another 10 days to have embryo transfer. I had thick lining history in the past so now the doc told me to change to use pill 2mg only a day. Does it sound correct? I had two failed egg donor cycles already and I had 15mm thickness first time and 21mm second time, my clinic still asked me to go ahead but failed, I never had three lines patterns and I am concerned if my endometrium is not good enough for implantation. I had done hysteroscopy nothing was found. I am confused if I should carry on with this cycle. Could please help? Many thanks