Plasma Estradiol Concentrations and Effect of HCG on Plasma Estradiol and Testosterone in Normal Subjects and Patients with Endocrine Disorders

Plasma estradiol concentrations were determined by radioimmunoassay in various endocrine disorders using antiserum to estradiol-17beta succinyl bovine serum albumin. Clinical significance and diagnostic value of plasma estradiol were assessed in hypothalamic-pituitary, adrenal and gonadal disorders. In general, estradiol concentration was correlated well with the degree of sexual maturity and was of great diagnostic use. Plasma estradiol in females mainly originated from the ovary, while the testis is the principal source of estradiol in males. The adrenal gland seemed to play a minor role as a source of estradiol at least in normal males and females. The role of estradiol in gynecomastia and in liver disease was also investigated. More than a half of the cases with gynecomastia had elevated concentrations of plasma estradiol, which probably explains the pathogenesis of this manifestation. Cirrhotic patients showed frequently hyperestrogenemia probably due to delayed disappearance of estradiol. In the study of stimulation with human chorionic gonadotropin (HCG), 3,000 IU daily for three days in ten normal men, the peripheral concentrations of esradiol showed maximum and fourfold increases 24 hours after the 1st injection of HCG. The testosterone levels, on the other hand, increased stepwise and reached a maximum of about two times preinjection levels 24 hours after the 3rd injection. In gonadal disorders, HCG produced various patterns of plasma estradiol and testosterone in accordance with the gonadal conditions and dissociated response patterns of both sex hormones were frequently found. The determination of plasma estradiol was useful in the study of the function of not only the ovary, but also the testis and the simultaneous measurement of plasma estradiol and testosterone after HCG administration presented interesting informations about pathophysiology of gonadal disorders.