Pituitary hCG

The anterior stalk of the pituitary secretes luteinizing hormone (LH), which shares an alpha subunit with hCG. In normal menstrual cycles, pituitary-generated hCG may be detectable at the time of the LH surge. Estrogen provides negative feedback for this LH secretion and acts as a suppressing agent. In patients in low-estrogen states (perimenopause, menopause, and status postoophorectomy), pituitary hCG may be secreted in increasing amounts, although only levels between 1 to 32 IU/L have been recorded.[2] To confirm a pituitary source for the hCG, patients are started on high-dose oral contraceptive pills to produce an exogenous source of estrogen. In general, patients with pituitary hCG will have their hCG levels suppressed after 3 weeks on this regimen.[2]