Upregulation refers to the increase in the number of receptor sites on the membrane. Estrogen and FSH upregulate LHCGR sites in preparation for ovulation. After ovulation, the luteinized ovary  maintains LHCGR s that allow activation in case there is an implantation. Upregulation in males requires gene transcription to synthesize LH receptors within the cell cytoplasm. Some reasons as to why downregulated LH receptors are not upregulated are: lack of gene transcription, lack of RNA to protein conversion and lack of cell membrane targeted shipments from Golgi.