Journal of Clinical Endocrinology & Metabolism, Vol 40, 518-521, Copyright © 1975 by Endocrine Society

ARTICLES

Circulating estradiol, estrone and gonadotropin levels following the administration of orally active 17beta-estradiol in postmenopausal women

SS Yen, PL Martin, AM Burnier, NM Czekala, MO Greaney Jr and MR Callantine

Ingestion of a single tablet containing 2 mg micronized 17beta- estradiol (E-2) produced marked increases in the serum concentrations of E-2 and estrone (E-1) in 9 postmenopausal women. The rise in circulating E-2 became significant within 2 h, reached a maximum (110 pg/ML; 437% increase) at 5 h, and remained significantly elevated at 8 h posttreatment. By 24 h, the serum E-2 concentration was not significantly different than baseline. In contrast, a more rapid (within 1 h) and pronounced (4-fold) increase in the serum concentration of E-1 was observed.This rise continued until a peak (467 pg/ml; 2000%) was reached 6 h posttreatment. Thereafter, the serum E-1 concentration declined progressively but was still significantly elevated (140 pg/ml; P smaller than 0.01) 24 h after treatment. Serum concentrations of FSH AND LH were significantly decreased within 6 and 3 h, respectively and both gonadotropins remained significantly suppressed 24 h following the ingestion of E-2. The ratios of circulating E-1: E-2 reported herein (ca. 3-6) were much higher than those observed by other investigators following iv E-2 (I.E., smaller than 1). Thus the data indicate that micronized E-2 peros is readily absorbed and that during this process a significant portion of the hormone is converted to E-1 by the gstrointestinal tract. In addition, 2 mg oral E-2 exerts significant biologic activity as assessed by serum gonadotropin suppression.

This article has been cited by other articles:

				S. Christin-Maitre, C. Laveille, J. Collette, N. Brion, and J.-Y. Reginster Pharmacodynamics of Follicle Stimulating Hormone (FSH) in Postmenopausal Women during Pulsed Estrogen Therapy: Evidence That FSH Release and Synthesis Are Controlled by Distinct Pathways J. Clin. Endocrinol. Metab., November 1, 2003; 88(11): 5405 - 5413. [Abstract] [Full Text] [PDF]

				C. K. Welt, Y. L. Pagan, P. C. Smith, K. B. Rado, and J. E. Hall Control of Follicle-Stimulating Hormone by Estradiol and the Inhibins: Critical Role of Estradiol at the Hypothalamus during the Luteal-Follicular Transition J. Clin. Endocrinol. Metab., April 1, 2003; 88(4): 1766 - 1771. [Abstract] [Full Text] [PDF]

				D. R. Plowchalk and J. Teeguarden Development of a Physiologically Based Pharmacokinetic Model for Estradiol in Rats and Humans: A Biologically Motivated Quantitative Framework for Evaluating Responses to Estradiol and Other Endocrine-Active Compounds Toxicol. Sci., September 1, 2002; 69(1): 60 - 78. [Abstract] [Full Text] [PDF]