Serum estrogen levels, effects

In this view, the effectiveness of raloxifene on leiomyoma reduction in postmenopausal women and in premenopausal women treated with GnRH-a could explain partially the ineffectivess of raloxifene in normally cycled women. Specifically, it seems, as supposed, that raloxifene achieves a clinical result only in patients with low serum estrogen levels. 

Medroxyprogesterone acetate (Fig. 46.13), administered by injection (Depo-Provera), orally, or delivered via lUD, effectively suppresses the HPO axis, induces anovulation, and reduces serum estrogen levels (83). This prevents menstruation and endometrial implant growth. As a result, endometriosis-related pain is minimized in approximately 90% of the patients. Drug therapy selection should reflect the fact that pharmacological therapy is likely to be required on a chronic basis. The progestins are fairly well tolerated and relatively inexpensive, but they are not without adverse effects. 

The serum estrogen level should increase three to four times the pretreatment baseline if the medications are effective and the client may be able to get pregnant. 

In animals as well as man, castration causes increased serum cholesterol levels. Androgens have variable effects on serum cholesterol, while estrogens induce a decrease (29). It has been postulated that the mechanism of action of estrogens on serum cholesterol levels might involve increased uptake of cholesterol by the Kupffer cells of the liver, with a subsequent increase in catabolism of cholesterol (30). 

Doran PM, Riggs BL, Atkinson EJ, Khosla S (2001) Effects of raloxifene, a selective estrogen receptor modulator, on bone turnover markers and serum sex steroid and lipid levels in elderly men. J Bone Miner Res 16 2118-2125... 

Reindollar R, Koltun W, Parsons A, Rosen A, Siddhanti S, Plouffe Jr L (2002) Effects of oral raloxifene on serum estradiol levels and other markers of estrogenicity. Fertil Steril 78 469-472... 

Williams DC, Paul DC, Black LJ (1991) Effects of estrogen and tamoxifen on serum osteocalcin levels in ovariectomized rats. Bone Miner 14 205-220... 

Based on this concept of correlation between high replication rate/high persistent mutation risk, Pike et al. (1983) formulated the hypothesis of breast tissue age and developed a mathematical model to predict the effects of exposure to ovarian hormones. This model incorporates reproductive and endocrine items related to breast cancer and is able to predict the relative risk of individual situations with results that are very close to those observed in clinical trials. According to this hypothesis, both the years of exposure and the circulating serum levels of estrogens are associated to short-term breast cancer risk in postmenopausal women (Toniolo et al. 1995). 

---