Synthesis and anti-tumor activity of a fluorinated analog of medroxyprogesterone acetate (MPA), 9alpha-fluoromedroxyprogesterone acetate (FMPA).

We synthesized 9alpha-fluoromedroxyprogesterone acetate (FMPA) in order to test whether it is a more potent anti-angiogenic agent than medroxyprogesterone acetate (MPA), which has been widely used as a therapeutic agent for breast and endometrium cancers. FMPA was previously synthesized in 10 steps (total yield: 1%). An efficient synthesis of FMPA has been achieved in 6 steps (total yield: 12%). We examined the anti-tumor effect of FMPA, complexed with dimethyl-beta-cyclodextrin (DM-beta-CyD), on rat mammary carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA). FMPA showed great anti-tumor effect on DMBA-induced rat mammary carcinomas.

Alternative hormone replacement regimens: is there a need for further clinical trials?

PURPOSE OF REVIEW: To review the randomized trials of hormone replacement therapy. RECENT FINDINGS: Studies have shown that conjugated equine estrogen 0.625 mg a day plus medroxyprogesterone acetate 2.5 mg a day increased the risk of cardiovascular events during the first year of treatment in women both with and without coronary heart disease. Conjugated equine estrogen plus medroxyprogesterone acetate also increased the overall risk of myocardial infarction and stroke in women without coronary heart disease, and myocardial infarction or death in women with coronary heart disease, and also increased the risk of breast cancer, cognitive decline and dementia. Unopposed, oral 17B-estradiol increased the risk of stroke during the first 6 months of treatment in women with a previous stroke. Oral 17B-estradiol with or without cyclic progestin had no effect on the progression of atherosclerosis or reinfarction. Transdermal 17B-estradiol plus cyclic progestin was associated with a non-significant increase in coronary heart disease events in women with coronary heart disease. Compared with placebo, cardiovascular events increased in the ongoing estrogen-only arm of the Women's Health Initiative, indicating that unopposed conjugated equine estrogen is unlikely to be cardioprotective. However, oral 17B-estradiol retarded the progression of subclinical atherosclerosis in younger women without coronary heart disease. SUMMARY: Hormone replacement therapy should not be initiated for the primary or secondary prevention of coronary heart disease in women. A trial of 17B-estradiol started at menopause in women without coronary heart disease should be considered.

Angiostatic activities of medroxyprogesterone acetate and its analogues.

The effects of medroxyprogesterone acetate (MPA) (I) and related compounds (II-VI) upon angiogenesis induced by basic fibroblast growth factor (bFGF) or transforming growth factor-alpha (TGF-alpha) were investigated using a rabbit corneal system for assay of angiogenesis. Dexamethasone (Dex) was used as a positive control. The MPA analogues tested were 6,6'-dehydro-MPA (II), megestrol acetate (III), 1-dehydromegestrol acetate (IV), melengestrol acetate (V), and 1-dehydromelengestrol acetate (VI). The inhibitory activities of these steroids using bFGF were in the order: Dex = MPA = (VI) = (V) > (IV) > (III). Steroid (II) was inactive. 5 alpha-dihydrotestosterone was weakly active, while estradiol-17 beta and progesterone were inactive. The angiostatic activity of MPA was completely abolished by mefipristone (RU 486) which showed no anti-angiogenic activity in this assay. With TGF-alpha, the order of angiostatic activities was Dex = (VI) > (IV) > (III) > (V). Steroid (II) was again inactive. Dex, MPA, and all the MPA analogues except steroid (II) markedly inhibited the activity of plasminogen activator secreted by cultured calf pulmonary artery endothelial cells, but did not inhibit growth of these cells. The binding affinities of MPA and its analogues to glucocorticoid, progesterone and androgen receptors were determined, but were found not to be correlated with their angiostatic activities.

Digitaloid pregnanes promote potassium-sparing diuresis in the guinea pig.

The synthesis of 17 alpha-acetoxy-3 beta-[(beta-D-glucopyranosyl)oxy]- 6 alpha-methylpregn-4-en-20-one, the glucoside of medroxyprogesterone acetate (MPA-glu), is described. MPA-glu and 14-amino-20 beta-hydroxy-3 beta-[(alpha-L-rhamnopyranosyl)oxy]-5 beta, 14 beta-pregnane (LND 623), pregnane glycosides that bind to the digitalis receptor, and digoxin, a cardiac glycoside, were infused intravenously into the anesthetized guinea pig. Each of the three steroids significantly enhanced urinary volume and sodium excretion without affecting blood pressure and creatinine clearance. Potassium excretion was markedly enhanced by digoxin but unaffected by MPA-glu or LND 623. These observations conform to previous work that demonstrated, in the rat, potassium-sparing diuresis by the glucoside of 14 beta-hydroxyprogesterone, a cardiotonic pregnane. There is a dissociation between potency to inhibit [3H]ouabain binding and the extra ATPase actions of the digitaloid pregnanes.