alexa Progestin antagonism of estrogen stimulated 1,25-dihydroxyvitamin D levels.
Oncology

Oncology

Journal of Cancer Science & Therapy

Author(s): Bikle DD, Halloran BP, Harris ST, Portale AA

Abstract Share this page

Abstract Progestins are frequently used in combination with estrogen to prevent or treat postmenopausal osteoporosis. Progestins protect against the undesirable hyperplastic effects of estrogen on the endometrium. The possibility that progestins might antagonize the beneficial effects of estrogen on calcium homeostasis has received little attention. In this study we determined whether the addition of progestin to estrogen would alter the ability of estrogen to raise serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] levels. Women within 5 yr of menopause were treated with three cycles of oral unopposed estrogen [1 or 2 mg/day (3.67 or 7.34 mumol/day) 17 beta-estradiol (E2) for 25/30 days of each cycle] followed by three cycles of E2 plus progestin [10 mg/day (29 mumol/day) medroxyprogesterone on days 12-25]. E2 increased both total and free 1,25-(OH)2D concentrations in a dose-dependent fashion. These levels increased progressively over the three cycles of unopposed estrogen treatment. In contrast the vitamin D binding protein concentration reached maximal levels after one cycle of E2. With the addition of progestin, the levels of total and free 1,25-(OH)2D returned toward baseline although vitamin D binding protein levels remained elevated. PTH levels rose with both doses of E2 as serum calcium levels fell. Progestin did not significantly alter the effects of E2 on PTH or calcium. Our results raise the possibility that progestin may antagonize part of the salubrious effects of estrogen on calcium homeostasis. This article was published in J Clin Endocrinol Metab and referenced in Journal of Cancer Science & Therapy

Relevant Expert PPTs

Relevant Speaker PPTs

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords