Clinical uses of antiestrogens

UPLC-MS/MS method for the determination of tobacco-specific biomarker NNAL, tamoxifen and its main metabolites in rat plasma

Cigarette smoke is known to interact with tamoxifen-metabolizing enzymes and transporters and potentially affect its treatment outcome. 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAL) is an important metabolite of 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK) because it is frequently used as a biomarker to assess human smoke exposure. In order to study the potential pharmacokinetic interaction between cigarette smoke and tamoxifen in rats a UPLC-MS/MS method for the simultaneous determination of NNAL and tamoxifen along with its metabolites in rat plasma has been developed and validated. Analytes were extracted with methanol and separated on a HSS T3 column by a gradient elution with the mobile phase consisting of acetonitrile and water. The lower limits of quantitation ranged from 0.05 to 0.62 ng/mL. Precisions showed RSD <15.8% and accuracy in the range 80.6-116.0%. Mean analyte recoveries ranged from 76.9 to 108.4%. The method was successfully applied to study the effects of cigarette smoke condensate (CSC), NNK and benzo(a)pyrene pre-treatment on the pharmacokinetics of tamoxifen and its metabolites in rats. Significant effects of CSC, NNK, benzo(a)pyrene were observed on pharmacokinetics of tamoxifen and its metabolites. We also found that plasma NNAL levels are statistically significant correlated with plasma 4-hydroxy-tamoxifen and endoxifen.

Raloxifene: A Selective Estrogen Receptor Modulator for the Prevention of Osteoporosis

Objective:

To review the efficacy and safety of the selective estrogen receptor modulator raloxifene hydrochloride in the prevention of osteoporosis.

Data Sources:

A MEDLINE search (January 1966–May 1998) and unpublished data obtained from the manufacturer were used to identify relevant studies and review articles. Additionally, bibliographies of selected articles were reviewed. Only English-language articles on human studies were obtained.

Study Selection:

Literature was reviewed to evaluate the pharmacology, pharmacokinetics, therapeutic use, adverse effects, and drug interactions of raloxifene. Additional relevant citations were used in the introduction material and clinical controversy section.

Data Extraction:

Clinical trials reviewing raloxifene for the prevention of osteoporosis were evaluated.

Data Synthesis:

Raloxifene hydrochloride is a partial estrogen agonist that displays both estrogenic and antiestrogenic effects. As a result of binding to estrogen receptors, raloxifene therapy, like estrogen treatment, causes positive changes in biochemical markers of bone turnover such as serum osteocalcin, serum alkaline phosphatase, urinary pyridinoline cross-links, and urinary calcium excretion. In addition, raloxifene increases bone mineral density. Furthermore, raloxifene reduces total serum cholesterol and serum low-density lipoprotein cholesterol. Raloxifene has no effect on serum high-density lipoprotein cholesterol. As a selective estrogen receptor modulator, raloxifene does not display the deleterious effects of estrogen in endometrial or breast tissue. The most common adverse effects are hot flashes and leg cramping.

Conclusions:

Clinical trials have found that raloxifene is effective in the prevention of osteoporosis, making the drug an alternative choice for the prevention of osteoporosis in patients who are concerned about the proliferative effects of estrogen replacement therapy on the endometrium or breast tissue. Raloxifene may not be a good alternative in women experiencing troublesome hot flushes during menopause. The use of raloxifene in the treatment of osteoporosis and in the prevention of breast cancer is currently being evaluated.

Clomiphene citrate-induced severe hypertriglyceridemia

OBJECTIVE

To report a case of severe hypertriglyceridemia associated with clomiphene citrate (CC) treatment.

DESIGN

Case report.

SETTING

A patient referred to an endocrinology clinic of a state hospital.

PATIENT(S)

A 29-year-old, overweight woman with a history of polycystic ovary syndrome who had been given clomiphene citrate (CC) for ovulation induction and presented with severe hypertriglyceridemia. She had a family history of type 2 diabetes and hyperlipidemia.

INTERVENTION(S)

Clomiphene citrate treatment was discontinued, and gemfibrozil treatment at a dose of 1,200 mg/d was started.

MAIN OUTCOME MEASURE(S)

Serum lipid levels.

RESULT(S)

With the discontinuation of CC treatment and start of a specific lipid-lowering agent, the patient's lipid profile improved. After 3 months, CC therapy was restarted, and again severe hypertriglyceridemia developed, which resolved with the previous treatment strategies.

CONCLUSION(S)

Clomiphene citrate should be used cautiously in women having risk factors for dyslipidemia, and, even in the presence of a normal lipid profile, lipid levels should be closely monitored when CC treatment is instituted.

Profiles of tamoxifen-related side effects by race and smoking status in women with breast cancer

BACKGROUND

Tamoxifen (TAM) is a selective estrogen receptor modulator (SERM) that is widely used as adjuvant therapy in breast cancer patients; however, it is also associated with undesirable side effects. The goal of this study was to investigate TAM-related side effects, and determine profiles of side effects by race and by smoking status.

METHODS

A secondary data analysis was conducted using cross-sectional study data from 138 African American and Caucasian women with breast cancer taking TAM 20mg daily for at least 30 days prior to enrollment. Participants completed questionnaires that obtained information about demographic characteristics, reproductive history, health and lifestyle characteristics, TAM use and its related side effects. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals.

RESULTS

Compared to never smokers, a significantly greater percentage of current smokers reported ever experiencing TAM-related nausea (28.0% versus 5.0%, P=0.007), depression (40.0% versus 7.1%, P=0.001) and migraines (19.2% versus 1.7%, P=0.02). These differences remained statistically significant after controlling for race, age, obesity, tumor stage, and duration of TAM treatment. No significant differences by race were noted in women reporting TAM side effects.

CONCLUSION

The findings from this study suggest that current smokers with breast cancer should be informed of the increased probability of reporting TAM-related side effects such as nausea, depression and migraines, and counseled about smoking cessation which may reduce the incidence of these side effects.

Clomiphene-Induced Acute Pancreatitis without Hypertriglyceridemia

Acute pancreatitis may be caused by drugs. In the literature, there are more than 260 different drugs that have been blamed for causing pancreatitis. Among these drugs, only 1 case has been reported as clomiphene-induced acute pancreatitis. However, in this single case, there was concomitant hypertriglyceridemia. We report the case of a woman who developed 2 attacks of acute pancreatitis without hypertriglyceridemia while receiving treatment with clomiphene.

Small optic cup sizes among women using tamoxifen: assessment with scanning laser ophthalmoscopy

PURPOSE

There is a substantial literature showing that the selective estrogen receptor modulator tamoxifen can block swelling-activated chloride channels, such as those in astrocytes. This study aimed to test the hypothesis that anatomic characteristics consistent with swelling may be measured within the optic nerve head (ONH) of tamoxifen users whose ONH appearance is considered within normal limits.

METHODS

Indices of ONH topography were measured using the Heidelberg Retina Tomograph II (HRT) for two populations of women ages 40-69 years: (1) subjects using tamoxifen (20 mg/day) as adjuvant therapy after successful primary treatment for breast cancer and (2) control subjects not using any hormonal medication. All subjects had excellent visual acuity (with 20/20 or better in the test eye), and all appeared to be free of eye disease, as based on conventional photographic assessment. The study design was cross-sectional. The various ONH indices were assessed as functions of the duration of tamoxifen use.

RESULTS

The optic cups of short-term tamoxifen users (<or=2 years) were significantly smaller in both the lateral and axial directions than the optic cups of the control subjects. Of the 27 short-term users, 23 had cup volumes smaller than the median value for the control subjects. The cup sizes of long-term users (> 2 years, <or=5 years) were not distinguishable from those of the control subjects. The presence of small cups among short-term users did not depend on subjects' medical histories prior to tamoxifen use. Disk margin indices were not related significantly to the duration of tamoxifen use.

CONCLUSIONS

Small cup sizes consistent with localized subclinical swelling are not rare among short-term tamoxifen users. Thus, small cups are not likely to be a manifestation of a cumulative-dose toxicity. Instead, they probably result from other causes, possibly involving the action of tamoxifen on estrogen receptors. Further investigation with longitudinal and interventional methodologies is needed to definitively interpret the results.

Infertility, ovulation induction treatments and the incidence of breast cancer--a historical prospective cohort of Israeli women

CONTEXT

Ovulation induction drugs may be associated with increased breast cancer risk. Results so far have been inconclusive.

OBJECTIVE

To evaluate the association between infertility, exposure to ovulation induction drugs and the incidence of breast cancer.

DESIGN

Historical prospective cohort and nested case-control study.

SETTING

Institutional practice

PATIENTS

About 5,788 women attending five infertility centers in Israel between 1964 and 1984.

INTENTION

Abstracting of medical records and telephone interviews.

MAIN OUTCOME MEASURE

Breast cancer incidence was determined through linkage with the National Cancer Registry database. Standardized incidence ratios (SIRs) and 95% confidence intervals were computed by comparing the observed to the expected cancer rates in the general population. In addition, a nested case-control study within the cohort was performed with interviews of breast cancer cases and two matched controls.

RESULTS

The study cohort included 120,895 women years of follow-up. Compared to 115.2 expected breast cancer cases, 131 cases were observed (SIR = 1.1; 95% CI 0.9-1.4). Risk for breast cancer was significantly higher for women treated with clomiphene citrate (SIR = 1.4; 95% CI 1.0-1.8). Similar results were noted when comparisons were carried out between treated and untreated women, and when multivariate models were applied. In the nested case-control study, higher cycle index (OR = 2.2; 95% CI 1.0-4.8) and treatment with clomiphene citrate (OR=2.7; 95% CI 1.3-5.7) were associated with higher risk for breast cancer.

CONCLUSION

Infertility and usage of infertility drugs in general are not associated with increased risk for breast cancer. However, for infertile women treated with clomiphene citrate, breast cancer risk is elevated.

The color appearance of stimuli detected via short-wavelength-sensitive cones for breast cancer survivors using tamoxifen

This study compared color appearance data for two populations of middle-aged women: (1) women using the selective estrogen receptor modulator tamoxifen as adjuvant therapy following successful treatment for early-stage breast cancer, and (2) healthy amenorrheic (peri- or post-menopausal) control subjects not using any hormonally acting medications. A 3-alternative forced-response paradigm (with "blue", "lavender", or "white" as the allowable responses) was used for assessing the perceived color of 440-nm foveal test stimuli superimposed on a larger 3.6 log td 580-nm background. In contrast to the control subjects, the majority of tamoxifen users described the test stimuli as "white", whether at threshold or slightly suprathreshold. Threshold-sensitivity measurements themselves appeared less effective for distinguishing between subject groups. The results show that a simple color-naming procedure can reveal alterations of foveal short-wavelength-sensitive cone-mediated visual function that are common among tamoxifen users.

Polymorphisms in cytochrome P4503A5 (CYP3A5) may be associated with race and tumor characteristics, but not metabolism and side effects of tamoxifen in breast cancer patients

Tamoxifen (TAM) is widely used for treatment and prevention of breast cancer. TAM is metabolized by cytochrome P450 (CYP450) enzymes, including CYP3A5. Although two genetic polymorphisms in CYP3A5 are known (CYP3A5*3 and CYP3A5*6), the effects of these polymorphisms on TAM metabolism, TAM side effects, and tumor characteristics are unknown. Thus, this work tested the hypothesis that CYP3A5 polymorphisms are associated with differential TAM levels, TAM side effects, and tumor characteristics in breast cancer patients. Postmenopausal women with breast cancer (n=98) were recruited from a single cancer center. Polymorphic status was established using polymerase chain reactions (PCR). The associations between polymorphic status, race, TAM levels, side effects, and tumor characteristics were assessed using t-tests and logistic regression models. The data indicate that 40.7% of the breast cancer patients had the CYP3A5*3 polymorphism, and 9.1% had the CYP3A5*6 polymorphism. In addition, Caucasian women were 26 times more likely to carry the CYP3A5*3 polymorphism than African American (AA) women, whereas AA women were nine times more likely to carry the CYP3A5*6 polymorphism than Caucasian women. No significant differences were seen in TAM or TAM metabolite levels or TAM side effects by polymorphic status. There was a significant difference, however, in mean tumor size in women with the CYP3A5*6 polymorphism (3.6+/-0.98 cm) compared to those without the polymorphism (2.0+/-0.18 cm) (P<0.02). Taken together, these data suggest that racial differences in CYP3A5 polymorphisms exist although the polymorphisms do not appear to be associated with levels of TAM metabolites and side effects.

Association of tamoxifen (TAM) and TAM metabolite concentrations with self-reported side effects of TAM in women with breast cancer

The positive effects of tamoxifen (TAM) on breast cancer recurrence and survival as well as on overall mortality have led to its use as the predominant adjuvant therapy among women with breast cancer. However, the association of TAM intake with undesirable side effects has been reported in numerous studies. This analysis was carried out to assess whether the concentrations of TAM or TAM metabolites, N -desmethyltamoxifen ( N -DMT) and 4-hydroxytamoxifen (4-OHT), were associated with self-reported side effects of TAM. Participants were 99 breast cancer patients who had been taking TAM for at least 30 days. Each participant completed a questionnaire that was used to ascertain whether she experienced certain specific symptoms while taking TAM. In addition, each woman provided a blood sample that was used to measure plasma concentrations of TAM, N -DMT, and 4-OHT by high performance liquid chromatography. Results of the analysis showed that women who experienced at least one TAM-related side effect had significantly higher levels of TAM than women not experiencing any TAM-related side effects. Furthermore, women who reported experiencing visual problems had significantly higher levels of both TAM and N -DMT compared to those women who reported experiencing no visual problems. The levels of 4-OHT were negatively associated with the occurrence of vaginal discharge. The results of this study suggest that the self-reported occurrence of certain symptoms during TAM treatment is related to TAM metabolism. Future studies should assess subgroups of women with specific TAM and TAM metabolite profiles to determine whether alternate, equally effective therapies would decrease their risk of experiencing certain undesirable side effects.

Aging May Be Associated with Concentrations of Tamoxifen and Its Metabolites in Breast Cancer Patients

BACKGROUND

Although tamoxifen (TAM) is the predominant adjuvant therapy for estrogen receptor positive (ER(+)) breast tumors, 50% of breast cancer patients do not respond positively to this therapy, or they experience adverse side effects. This variability in TAM responsiveness may be due to differences in TAM metabolism that stem from differences in race, age, and body mass index (BMI). Thus, the purpose of this study was to test the hypothesis that race, age, and BMI are associated with the metabolism of TAM to two primary metabolites, N-desmethyltamoxifen (N-DMT) and 4-hydroxytamoxifen (4-OHT).

METHODS

The study design was cross-sectional, and data were analyzed using independent sample t tests and multiple linear regression models. Breast cancer patients (n = 99) taking TAM for at least 30 days were recruited from a local hospital clinic. Each participant provided informed consent, completed a questionnaire, and donated a blood sample. The questionnaire was used to ascertain race, age, and BMI. The blood samples were used to measure plasma concentrations of TAM, N-DMT, and 4-OHT.

RESULTS

Plasma concentrations of TAM, N-DMT, and 4-OHT differed among individual patients. Age, but not race and BMI, was positively associated with plasma concentrations of TAM and N-DMT, even after adjustment for potential confounders (p = 0.02 for TAM and p = 0.03 for N-DMT).

CONCLUSIONS

This study suggests that aging may alter the metabolism of TAM. As increased levels of TAM and TAM metabolites may provide a possible explanation for why older women taking TAM are at increased risk for adverse side effects, future studies should determine whether age-related differences in the concentrations of TAM and TAM metabolites are associated with differences in TAM toxicity or responsiveness.

Review of raloxifene and its clinical applications in osteoporosis

Raloxifene, a selective oestrogen receptor modulator, is currently utilised for both the prevention and treatment of postmenopausal osteoporosis. Prevention studies with raloxifene have demonstrated preservation of bone density, suppression of markers of bone turnover and maintenance of normal bone histology for up to 4 years in young postmenopausal women. The Multiple Outcomes of Raloxifene Evaluation (MORE) trial, the pivotal treatment trial of raloxifene, demonstrated significant reductions in the risk of vertebral fractures after 1 and 3 years, which is comparable to other currently available agents. Significant reductions in non-vertebral fractures with raloxifene have not been demonstrated yet. In addition to the effects of raloxifene on bone, a number of beneficial non-skeletal effects have been reported on the breast, uterus and cardiovascular system. These latter findings are mainly derived from secondary end points and analyses of the large osteoporosis studies with raloxifene. Two large, prospective, randomised, double-blind studies examining the effects of raloxifene on breast cancer prevention and cardiovascular protection are now underway. Recent information on the effects of raloxifene in postmenopausal osteoporosis, breast cancer prevention and cardiovascular disease in high-risk women and those with uterine disorders is reviewed in this article.

Comparative tolerability of first-generation selective estrogen receptor modulators in breast cancer treatment and prevention

In general, the selective estrogen receptor modulators (SERMs) currently indicated for the treatment and prevention of breast cancer, i.e. tamoxifen and toremifene, are fairly well tolerated. However, tamoxifen has been shown to induce hepatocellular carcinomas in rats, but not in humans, and can increase the risk of endometrial cancer in humans by two to three times. Other potentially serious adverse effects which have been associated with tamoxifen and toremifene therapy include vasomotor symptoms, an increased risk of venous thromboembolic events, and an increased incidence of cataracts and ocular toxicity, fatty liver, and nonmalignant hepatic and uterine changes. In addition, long term tamoxifen use almost always results in resistance to the drug and, indeed, has actually been shown to promote tumour proliferation in human breast cancer cells. Both tamoxifen and toremifene display drug interactions with a variety of drug classes. The adverse events associated with these compounds have raised significant concerns regarding their widespread use for the treatment and prevention of breast cancer. In addition, because of the weakness and scarcity of the data on toremifene, any conclusions about its tolerability remain tentative until outcomes of ongoing clinical trials in the adjuvant setting are known. A third SERM, raloxifene, is the focus of several large randomised trials examining its efficacy in the prevention of breast cancer. At present, each potential adverse event needs to be weighed against potential benefits in the decision to undergo SERM treatment. An array of therapies is currently available for patients with breast cancer and women at increased risk of disease; the risk-to-benefit ratio for each agent should be carefully examined in determining the most advantageous regimen.

Cardiovascular effects of raloxifene hydrochloride

Raloxifene hydrochloride binds to the estrogen receptor and shows tissue-selective effects; thus, it belongs to a class of drugs recently described as selective estrogen receptor modulators (SERMs). Tissue selectivity of raloxifene may be achieved through several mechanisms: the ligand structure, interaction of the ligand with different receptor subtypes in various tissues, and intracellular events after ligand binding. Raloxifene has estrogen-agonist effects on bone and lipids and estrogen antagonist effects on the breast and uterus. In addition to its well established effects on osteoporosis, recent preclinical and clinical findings suggest that raloxifene also possesses beneficial effects on the cardiovascular system. These findings indicated that raloxifene may have cardioprotective properties without an increased risk of cancer or other side effects. Raloxifene has been shown to reduce total and low-density lipoprotein cholesterol concentrations in plasma, an effect similar to that produced by estrogens. Unlike estrogens, however, raloxifene does not increase high-density lipoprotein cholesterol and triglyceride levels in plasma. Endothelium is thought to play an important role in the genesis of atherosclerosis. Several lines of evidence suggest that an intervention with endothelial function might influence the progression of coronary disease and the incidence of cardiovascular events. Raloxifene increases the nitric oxide/endothelin-1 ratio, and improves endothelium-dependent vasomotion in post-menopausal women to the same extent as estrogens. Furthermore, in two randomized trials on post-menopausal women raloxifene reduced homocysteine levels, another independent risk factor for the development of cardiovascular disease. Although estrogens remain the drugs of choice in the hormonal therapy of most postmenopausal women, raloxifene may represent and alternative in women who are at risk of coronary artery disease.

The effect of raloxifene on the uterine weight response in immature mice exposed to 17beta-estradiol, 1,1,1-trichloro-2, 2-bis(p-chlorophenyl)ethane, and methoxychlor

OBJECTIVE

The purpose of this study was to determine the effects of raloxifene on the uterine responses to both estradiol and the environmental estrogens 1,1,1-trichloro-2, 2-bis(p-chlorophenyl)ethane and methoxychlor in immature mice.

STUDY DESIGN

Immature female mice received the following compounds alone or in combination: sesame oil (control), 17beta-estradiol 1 mg/kg body weight, tamoxifen 1 mg/kg body weight, raloxifene 5 mg/kg body weight, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane 10 mg/kg body weight, and methoxychlor 10 mg/kg body weight. The animals were treated subcutaneously once a day for 5 consecutive days with the compound or compounds of interest in 0.1 mL sesame oil. Approximately 24 hours after the final treatment the animals were killed and the uteri were excised, stripped of remaining fat and mesentery, and weighed. Groups were analyzed with analysis of variance.

RESULTS

Estradiol increased the mean (+/-SE) weight from 20 +/- 6.4 mg (as measured in the control group) to 77 +/- 6.2 mg. Tamoxifen increased uterine weight to 60 +/- 6.2 mg; however, raloxifene had no effect on uterine weight. Both 1,1,1-trichloro-2, 2-bis(p-chlorophenyl)ethane and methoxychlor increased uterine weight significantly, to 82 +/- 2.4 mg and 35 +/- 6.0 mg respectively. When raloxifene was coadministered with 17beta-estradiol it did not block the increase in uterine weight; however, when raloxifene was coadministered with 1,1,1-trichloro-2, 2-bis(p-chlorophenyl)ethane or methoxychlor, it completely blocked the uterine weight gain induced by either xenoestrogen.

CONCLUSION

Raloxifene blocked the xenoestrogens 1,1,1-trichloro-2, 2-bis(p-chlorophenyl)ethane and methoxychlor but did not block 17beta-estradiol in the mouse model described. These results suggest that the xenoestrogens exert their estrogenic activities through a different site on the estrogen receptor or through a different mechanism than 17beta-estradiol.

The reversible effects of raloxifene on luteinizing hormone levels and ovarian morphology in mice

Raloxifene is a selective estrogen receptor modulator that has estrogen agonist effects on bone and serum lipids and estrogen antagonist effects on breast and uterine tissues. This study assessed the effects of raloxifene hydrochloride (HCl) treatment on circulating luteinizing hormone (LH) levels and ovarian morphology in sexually mature, 15-week-old, female CD-1 mice. Mice were maintained on diets providing average daily doses of 0 or 233 mg/kg raloxifene for 2 weeks (Study 1) or 0, 7.9, or 236 mg/kg raloxifene for 4 weeks (Study 2). At the end of the treatment period, blood samples were collected every 2 hours for 24 h in Study 1 (5 mice per group) and at 10:00 a.m. and 10:00 p.m. in Study 2 (8 mice per group). Serum LH levels were measured by radioimmunoassay. Ovarian histomorphology was evaluated in the 10 mice per group (Study 1) and the 8 mice per group (Study 2). For the reversibility phase (Study 2), mice were fed untreated diets for 3 weeks; serum LH levels and ovarian histomorphology were then assessed. Raloxifene treatment at 233 mg/kg/day for 2 weeks (Study 1) significantly elevated circulating LH levels by 4- to 7-fold compared with control. Raloxifene-treated mice had elevated LH levels sustained over the 24-h sampling period and did not exhibit the preovulatory LH surge evident in some control mice at the 4:00 p.m., 6:00 p.m., and 8:00 p. m. time points. Mice treated with 236 mg/day raloxifene for 4 weeks (Study 2) had elevated LH levels (4.4-fold compared to control), whereas mice exposed to 7.9 mg/kg/day raloxifene had a slight, nonsignificant increase in LH (2-fold compared to control). In both dose groups, LH levels were indistinguishable from controls 3 weeks after raloxifene treatment was discontinued. The ovaries in six of the eight mice treated with 7.9 mg/kg/day raloxifene had dilated and/or anovulatory follicles. One mouse in this group had a single hemorrhagic follicle; however, corpora lutea distribution was normal, indicating that ovulation was occurring. Raloxifene-treated mice in Study 1 and mice treated with a comparable raloxifene dose (236 mg/day) in Study 2 had histomorphological changes in the ovary indicative of arrested follicular maturation, including anovulatory hemorrhagic follicles, some developing follicles, and very few corpora lutea. At the end of the reversibility phase, hemorrhagic follicles were no longer evident and follicular maturation and corpora lutea distribution were normal. Raloxifene treatment in mice produces a dose-dependent, sustained elevation in serum LH levels and is associated with changes in ovarian follicular morphology. These changes are reversible upon discontinuation of raloxifene treatment.

Clomiphene-induced severe hypertriglyceridemia and pancreatitis

Clomiphene has been available for clinical use since 1960 and has been successfully used to aid fertility in women with certain anovulatory disorders. It is a synthetic estrogen analog, of the triphenylethylene derivative group, and its biochemical structure is similar to that of tamoxifen. Estrogen and tamoxifen lower total and low-density lipoprotein cholesterol and increase triglyceride and high-density lipoprotein cholesterol levels. In patients with baseline hypertriglyceridemia, these agents can induce severe hypertriglyceridemia and pancreatitis. The actions of clomiphene on lipid metabolism have not been studied, and to our knowledge, no cases of severe hypertriglyceridemia related to the use of clomiphene have been described. We report the case of a woman who developed 2 episodes of clomiphene-induced hypertriglyceridemia and pancreatitis while receiving this drug for treatment of infertility. Given the striking structural similarity between clomiphene and tamoxifen, it is likely that clomiphene is capable of inducing severe hypertriglyceridemia in patients with certain underlying lipid disorders by a mechanism similar to that of tamoxifen.

The effects of the estrogen receptor blocker, Faslodex (ICI 182,780), on estrogen-accelerated bone maturation in mice

Sex steroids accelerate bone maturation, but it is believed that estrogen action is needed for terminal epiphyseal fusion. In this study, we investigated the effects of a new estrogen-blocking agent, Faslodex (ICI 182,780), on estrogen-accelerated skeletal maturation in immature mice. On day-of-life 2 through 8, mice pups received either estradiol (5 microg/100 g body weight), Faslodex (100 microg/100 g body weight), a combination of Faslodex + estradiol, or vehicle alone. Skeletal maturation was assessed with a scoring system based on the size and appearance of epiphyseal plates in the forepaw and the lumbar spine. Estradiol caused acceleration of bone maturation in our mouse model (p < 0.05). Faslodex blocked the effect of estrogen, such that the mice receiving Faslodex + estradiol did not vary significantly from controls. Faslodex may prove useful in the treatment of patients with diseases causing rapid skeletal maturation, such as precocious puberty.

Selected hormonal agents in gynecology

Hormonal agents are used to treat many conditions, including endometriosis, amenorrhea, fibroids, and dysfunctional uterine bleeding. Because women visit their care provider for various gynecologic problems more than any other reason, application of therapeutic uses in this rapidly expanding field is essential for nurses working in endocrine gynecology. Strategies for hormone use are discussed in light of the goals of patient education and treatment in the areas of pain relief, fertility, and cycle regulation.

Modern antioestrogens and the coming revolution in women's health care

This review will focus on antioestrogens and selective oestrogen receptor modulators (SERMS). The more traditional SERMS, clomiphene citrate and tamoxifen, will be reviewed along with such modern drugs as raloxifene and faslodex, with emphasis upon their actions on breast, uterus, bone and lipids. The future potential of these medications, in the management of oestrogen-dependent gynaecological conditions such as endometriosis, dysfunctional uterine bleeding, fibroids and breast cancer will be discussed.

Post-menopausal women and osteoporosis: available choices for maintenance of skeletal health

OBJECTIVE

To briefly summarize the therapeutic choices for osteoporosis prevention which are currently available to post-menopausal women.

METHODS

Results of randomized clinical trials and epidemiological studies in postmenopausal women, and pre-clinical studies in ovariectomized rats were summarized.

RESULTS

Estrogen combined with progestogen in hormone replacement therapy (HRT) is effective in relieving perimenopausal symptoms and maintaining bone mineral density. However, the increased breast cancer risk associated with long-term HRT use makes it a less desirable option for many women. Selective estrogen receptor modulators (SERMs), such as raloxifene, are also effective in maintaining bone density, without stimulating the breast or uterus. However, SERMs do not relieve perimenopausal hot flashes.

CONCLUSION

HRT is effective for acute relief of perimenopausal symptoms, but for women who are unwilling or unable to take HRT long-term, SERMs such as raloxifene are a useful therapy for the prevention of osteoporosis.

The effect of estrogens and antiestrogens in a rat model for hot flush

The present studies evaluated the effect of estrogens and the selective estrogen receptor modulator (SERM) tamoxifen and raloxifene in a rat model for hot flush. In this model, ovariectomized rats were treated for 8 or 9 days either sc or po. Rats were dependent to morphine by implanting a morphine pellet (75 mg each) sc on days 3 and 5 of treatment. On the last day of treatment, a thermistor, connected to a data acquisition system, was placed on the tail of each animal and morphine addiction was withdrawn by naloxone injection (1.0 mg/kg, sc). Temperature measurements were taken for 1 h under ketamine (80 mg/kg, im) anesthesia. In general, vehicle treated rats showed a 5-6 degrees C elevation of their tail skin temperature with the peak occurring about 15 min after naloxone injection. 17 alpha-Ethinyl estradiol (EE) was evaluated both sc and po using a broad range of doses. The IC50 for inhibition of tail skin temperature rise was approximately 0.1 mg/kg, sc and 0.2 mg/kg, po. 17 beta-Estradiol and 17 alpha-estradiol were also active in this model whereas non-estrogenic steroids were inactive. Raloxifene and tamoxifen were tested for estrogen agonist and antagonist activity administered sc and po. Raloxifene did not demonstrate reproducible estrogen agonist activity at doses up to 10 mg/kg, whereas it demonstrated significant antagonistic activity at the 10 mg/kg dose regardless of the route of administration. Tamoxifen exhibited significant estrogen agonist activity at all doses tested (0.1-10.0 mg/kg) and was a significant antagonist of EE at the 1.0 mg/kg dose. Our results demonstrate the potential utility of this model to evaluate and discriminate among classes of compounds with varying degrees of estrogen agonist and antagonist activity.

Other medical management of uterine fibroids

Several medicines are emerging with the potential to treat symptomatic uterine fibroids. Anti-progesterone compounds seem particularly promising. These drugs have been widely used for nearly 20 years and are known to be safe; medical politics have prevented their proper investigation for uterine fibroids. In particular, the value of mifepristone, 50 mg per day for 3 months, seems particularly promising. Further investigation is clearly warranted for this medicine. Several anti-oestrogen compounds have recently become available and may also be useful for the medical treatment of symptomatic uterine fibroids. This includes the possibility of the use of selective oestrogen receptor modulators as well as the prospect of the use of pure anti-oestrogens. On a longer time frame, inhibitors of angiogenesis may be useful. These medicines would act upon the blood supply to uterine fibroids. Physicians also have an obligation to investigate scientifically any promising naturopathic treatment that appears to have possible activity for symptomatic fibroids.

Oestrogenic effects of ICI 182,780, a putative anti-oestrogen, on the secretion of oxytocin and prostaglandin F2 alpha during oestrous cycle in the intact ewe

The effect of ICI 182,780, oestrogen antagonist, on the concentration of oxytocin and uterine PGF2 alpha was investigated in intact Border Leicester Merino cross ewes during the late oestrous cycle. Twelve cyclic ewes (n = 6 per group) were randomly assigned to receive, at 6 h intervals, intra-muscular injection of either peanut oil or ICI 182,780 (1.5 mg kg-1 day-1) in oil for 2 days, starting at 1900 h on day 13 until 1300 h on day 15 post-oestrus. Hourly blood samples were collected via a jugular catheter from 0800 h on day 14 for 37 h and then daily over days 16, 17 and 18 post-oestrus. Peripheral plasma concentrations of oxytocin, the metabolite of prostaglandin F2 alpha, 15-keto-13,14-dihydro-prostaglandin F2 alpha, (PGFM) and progesterone were measured by radioimmunoassay. All ewes treated with ICI 182,780 exhibited functional luteal regression as indicated by a marked reduction in plasma progesterone concentrations to less than 1000 pg/ml over the period of 18-36 h during sampling period on days 14 and 15 of the oestrous cycle. In five of six vehicle-treated ewes, progesterone concentrations declined between day 16 and day 18 post-oestrus. In the remaining control ewe, progesterone concentrations reach less than 1000 pg/ml within 36 h of the commencement of the sampling period. During the frequent sampling period, the number of oxytocin pulses in the ICI 182,780 treated ewes was significantly higher compared to control ewes (2.7 +/- 0.3 vs. 0.8 +/- 0.3). The mean amplitude of oxytocin pulses observed was also greater (70.4 +/- 19.5 pg/ml) in ewes treated with ICI 182,780, but was not significantly different from the control ewes (33.5 +/- 12.9 pg/ml). Oxytocin pulses may however have occurred following the initial two ICI 182,780 injections but before commencing blood sampling. The oxytocin pulses were detected at a mean of 3.2 +/- 0.2 h following each injection with ICI 182,780 during blood sampling. In the ICI 182,780-treated ewes, the pulsatile pattern of plasma PGFM in jugular blood samples over the 37 h sampling period on days 14 and 15 post-oestrus had a higher amplitude (512.9 +/- 158.9 vs 121.7 +/- 78.7 pg/ml) and pulse area (618.1 +/- 183.3 vs 151.5 +/- 102.9 (ph/ml)tau) compared to the vehicle-treated ewes (P < 0.05) respectively.. The average number of PGFM pulses observed per ewe was 3.0 +/- 0.7 in the ICI 182,780-treated group and was significantly (P < 0.02) higher than the number of pulses (0.5 +/- 0.3) observed in ewes treated with vehicle alone. The PGFM pulses were detected at 4.2 +/- 0.6 h following each injection with ICI 182,780 during blood sampling. The percentage of PGFM pulses that occurred coincidently with significant elevation of oxytocin concentrations was 44.4% in ICI 182,780-treated compared to 66.6% in control ewes. We conclude that administration of oestrogen antagonist ICI 182,780 accelerated development of the luteolytic mechanism by enhancing pulsatile secretion of oxytocin and PGFM which suggests that ICI 182,780 acts as an agonist for oxytocin and prostaglandin f2 alpha release in intact ewes when administered at 1.5 mg/kg/day over day 13 to 15 post-oestrus.

Reproductive endocrine and endometrial effects of raloxifene hydrochloride, a selective estrogen receptor modulator, in women with regular menstrual cycles

Previous studies of raloxifene conducted in animal models and postmenopausal women have demonstrated antiestrogenic action on the endometrium. The purpose of this first study of raloxifene in women with normal menstrual cycles was to determine its reproductive endocrine and endometrial effects. In part I, raloxifene (400 mg) was administered for 5 days in the follicular, periovulatory, or luteal phase of the menstrual cycle (n = 12). In part II, women were randomized to receive raloxifene (100 or 200 mg) for 28 days beginning on day 3 of the cycle (n = 19). All women ovulated in both parts of the study. Raloxifene did not alter the length of the menstrual cycle or the day of the LH surge. A 5-day course of raloxifene administered in any phase of the cycle elevated FSH area under the curve (AUC) for the entire cycle and estradiol AUC for the second half of the cycle compared with those in control cycles. In part II, raloxifene also appeared to increase the FSH AUC and estradiol AUC. Raloxifene decreased the number of gland mitoses in follicular phase endometrial biopsies. Subtle effects suggestive of gland-stromal dysynchrony were noted in a limited number of the secretory phase endometrial biopsies. This study has demonstrated that 1) raloxifene does not prevent ovulation in women with normal menstrual cycles; 2) ovarian estrogen production will continue, and in some cases increase, in response to raloxifene; and 3) antiestrogenic effects of raloxifene on the endometrium are subtle in the endocrine milieu of normal to high circulating estradiol concentrations.