Circulating estradiol, estrone and gonadotropin levels following the administration of orally active 17beta-estradiol in postmenopausal women.
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.
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D003864:Depression, Chemical; D004958:Estradiol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004970:Estrone / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008593:Menopause; D008875:Middle Aged; D013268:Stimulation, Chemical; D013997:Time Factors
D004970:Estrone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone