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At least 55 records · Page 3Linked to original sources
PubMed1986

Effect of clomiphene citrate on the in vitro release of LH and FSH by the pituitary gland of the long-term ovariectomized rat pretreated with LRH or with LRH and oestradiol benzoate.

The effect of a combined in vivo pre-treatment with luteinizing hormone-releasing hormone (LRH) and either oestradiol benzoate (OB), clomiphene (-citrate) or OB plus clomiphene on the autonomous and the supramaximally LRH-stimulated in vitro secretion of LH and FSH by pituitary glands of long-term ovariectomized (OVX) rats was studied using a hemipituitary perifusion system. The concentration of LRH in the perifusion medium was 1 microgram/ml. Pre-treatment with LRH during 5 days was effected by means of sc implanted Alzet osmotic minipumps; control rats received a piece of silastic with the dimensions of a minipump. OB, 3 micrograms/injection, clomiphene 100 micrograms/injection or solvent were given on days 2 and 4 (day of perifusion: day 5). In rats not pre-treated with LRH neither OB, nor clomiphene changed the content of the pituitary gonadotropin stores. There was only a small but significant positive effect of the combined treatment with OB and clomiphene on the pituitary FSH content. LRH (partly) depleted the gonadotropin stores. This effect of LRH was potentiated by OB, but not by clomiphene. Clomiphene prevented the depletion-potentiating effect of OB. OB raised the LRH-stimulated secretion of LH and FSH as well as the autonomous secretion of LH. Clomiphene raised the LRH-stimulated (not the autonomous) secretion of LH and FSH. OB plus clomiphene had the same effect as OB alone. Clomiphene also raised the LRH-stimulated secretion of LH and FSH after pre-treatment with LRH, but OB did not do so: LRH prevented the stimulatory effect of OB but not of clomiphene. OB plus clomiphene had the same effect as OB alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Enhancement of antiproliferative effect of cis-diamminedichloroplatinum(II) by clomiphene and tamoxifen in human ovarian cancer cells.

In this study, we examined antiproliferative effect of clomiphene and tamoxifen alone and their combined effect on cis-diamminedichloroplatinum(II) (CDDP) by using human ovarian cancer cells (KF, KK, and MH cells) with different sensitivity to CDDP and MCF-7 cells derived from human breast cancer. KF, KK, and MH cells did not have estrogen receptor while MCF-7 cells had it. The KF cells were most sensitive to CDDP followed by KK, MCF-7, and MH cells. Similarly, the KF cells among three human ovarian cancer cell lines were most sensitive to clomiphene and tamoxifen alone. The MCF-7 cells had similar high sensitivity to both clomiphene and tamoxifen. When effects of clomiphene and tamoxifen on the protein kinase C (PKC) activity in the cancer cells were examined, the degree of inhibition of the PKC activity in the KF cells by clomiphene and tamoxifen was most marked and that by clomiphene was followed by those by KK, MH, and MCF-7 cells, while that by tamoxifen was, in increasing order, MH, MCF-7, and KK cells. Analyses of effects of clomiphene or tamoxifen on concentrations of CDDP required for 50% inhibition of cell proliferation (IC50) revealed that although the combined effects, in the KF and KK cells were only marginal, marked enhancement of antiproliferative effects of CDDP on the MH cells resistant to CDDP was obtained. When 5 x 10(6) cells were incubated with 100 microM CDDP for 3 hr, uptake of CDDP by MCF-7 cells was lowest, followed by MH, KK, and KF cells. The CDDP uptake by KF and KK cells was increased about 30-40% in the presence of clomiphene or tamoxifen. The CDDP uptake by the MH cells in which most marked enhancement of antiproliferative effect of CDDP was observed by a combination with clomiphene or tamoxifen was increased about 80-90% in the presence of clomiphene or tamoxifen. These results suggest that not only tamoxifen but also clomiphene can potentiate antiproliferative effect of CDDP in the ER-negative CDDP-resistant cancer cells by enhancing the CDDP uptake.

Adenocarcinoma↗
PubMed1989

Peri-implantation phase endometrial estrogen and progesterone receptors: effect of ovulation induction with clomiphene citrate.

The effects of clomiphene citrate on endometrial nuclear estradiol receptors and progesterone receptors were examined in 10 normal women during an untreated cycle (control) and during treatment with 50 mg clomiphene citrate and 150 mg clomiphene citrate daily on days 5 through 9. Concentrations and binding constants of the receptors were determined in endometrium obtained 8 to 12 days after midcycle luteinizing hormone surge. Scatchard plots for both estrogen receptors and progesterone receptors were linear, indicating only one type of high-affinity binding sites. In control cycles, estrogen receptor levels (mean +/- SEM) were 199.6 +/- 23.1 fmol/mg deoxyribonucleic acid, (n = 8) and were not significantly different from either 50 mg clomiphene citrate (180.5 +/- 19.1 fmol/mg deoxyribonucleic acid, n = 6) or 150 mg clomiphene citrate (194.3 +/- 35.2 fmol/mg deoxyribonucleic acid, n = 4). Similarly, the dissociation constants were unaffected by clomiphene citrate treatment. The concentrations of progesterone receptors in the control cycles (613 +/- 31 fmol/mg deoxyribonucleic acid, n = 5) and treatment cycles (50 mg clomiphene citrate -652.8 +/- 121 fmol/mg deoxyribonucleic acid, n = 6; 150 mg clomiphene citrate -592.6 +/- 31 fmol/mg deoxyribonucleic acid, n = 7) were also not significantly different. Clomiphene citrate also did not affect dissociation constants for progesterone receptors. Therefore, ovulation induction with clomiphene citrate apparently did not affect peri-implantation phase endometrial estrogen receptors and progesterone receptors or their respective binding constants.

Adult↗
PubMed2002

Effect of clomiphene on Ca(2+) movement in human prostate cancer cells.

The effect of clomiphene, an ovulation-inducing agent, on cytosolic free Ca(2+) levels ([Ca(2+)](i)) in populations of PC3 human prostate cancer cells was explored by using fura-2 as a Ca(2+) indicator. Clomiphene at concentrations between 10-50 microM increased [Ca(2+)](i) in a concentration-dependent manner. The [Ca(2+)](i) signal was biphasic with an initial rise and a slow decay. Ca(2+) removal inhibited the Ca(2+) signal by 41%. Adding 3 mM Ca(2+) increased [Ca(2+)](i) in cells pretreated with clomiphene in Ca(2+)-free medium, confirming that clomiphene induced Ca(2+) entry. In Ca(2+)-free medium, pretreatment with 50 microM brefeldin A (to permeabilize the Golgi complex), 1 microM thapsigargin (to inhibit the endoplasmic reticulum Ca(2+) pump), and 2 microM carbonylcyanide m-chlorophenylhydrazone (to uncouple mitochondria) inhibited 25% of 50 microM clomiphene-induced store Ca(2+) release. Conversely, pretreatment with 50 microM clomiphene in Ca(2+)-free medium abolished the [Ca(2+)](i) increase induced by brefeldin A, thapsigargin or carbonylcyanide m-chlorophenylhydrazone. The 50 microM clomiphene-induced Ca(2+)release was unaltered by inhibiting phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). Trypan blue exclusion assay suggested that incubation with clomiphene (50 microM) for 2-15 min induced time-dependent decrease in cell viability by 10-50%. Collectively, the results suggest that clomiphene induced [Ca(2+)](i) increases in PC3 cells by releasing store Ca(2+) from multiple stores in an phospholipase C-independent manner, and by activating Ca(2+) influx; and clomiphene was of mild cytotoxicity.

Brefeldin A↗
PubMed2003

Correction of insulin resistance and hyperandrogenism in polycystic ovary syndrome by combined rosiglitazone and clomiphene citrate therapy.

OBJECTIVE: To investigate the effects of combined rosiglitazone and clomiphene citrate versus clomiphene citrate monotherapy on serum insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels in polycystic ovary syndrome (PCOS) and to evaluate these therapeutic interventions in the link between hyperinsulinemia and hormonal perturbations in PCOS. METHODS: We performed a randomized clinical study at the King Abul-Aziz and Cairo University Hospitals. We studied 50 women with PCOS. Clinical diagnosis was based on hyperandrogenism; hyperinsulinism; oligomenorrhea; or amenorrhea, anovulatory cycles, and ultrasonographic findings. They were randomly assigned to two groups of 25 women each. One group was treated with rosiglitazone and clomiphene citrate; the other was treated only with clomiphene citrate. Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, dehydroepiandrosterone sulfate (DHEAS), free testosterone, IGF-1, and IFGBP-3 were measured by specific radioimmunoassays before and after treatment. RESULTS: Combined rosiglitazone and clomiphene treatment led to a significant reduction in area under the insulin curve (AUC insulin), whereas clomiphene monotherapy did not lead to this reduction. Both types of treatment induced a significant decrease in LH, LH:FSH ratio, free testosterone, and IGF1:IGBP-3 ratio and were associated with a significant increase in IGFBP-3 levels. These changes were more pronounced in PCOS patients treated with combined rosiglitazone and clomiphene than in those treated with clomiphene monotherapy. Regular menstrual cycles occurred in 72% of the former group and 48% of the latter. CONCLUSION: Combined rosiglitazone and clomiphene was an effective therapeutic regimen for correcting insulin resistance in patients with PCOS, possibly by reducing IGF1 bioavailability to the ovaries, thus modifying the hyperandrogenic intrafollicular milieu that occurs in PCOS. In addition, the clinical and hormonal responses were better than with clomiphene alone.

Adult↗
PubMed1998

Effects of metformin on spontaneous and clomiphene-induced ovulation in the polycystic ovary syndrome.

BACKGROUND: Obese women with the polycystic ovary syndrome are relatively unresponsive to the induction of ovulation by clomiphene. We hypothesized that reducing insulin secretion by administering metformin would increase the ovulatory response to clomiphene. METHODS: We performed oral glucose-tolerance tests before and after the administration of 500 mg of metformin or placebo three times daily for 35 days in 61 obese women with the polycystic ovary syndrome. Women who did not ovulate spontaneously were then given 50 mg of clomiphene daily for five days while continuing to take metformin or placebo. Serum progesterone was measured on days 14, 28, 35, 44, and 53, and ovulation was presumed to have occurred if the concentration exceeded 8 ng per milliliter (26 nmol per liter) on any of these days. RESULTS: Twenty-one women in the metformin group and 25 women in the placebo group were given clomiphene because they did not ovulate spontaneously during the first phase of the study. Among the 21 women given metformin plus clomiphene, the mean (+/-SE) area under the serum insulin curve after oral glucose administration decreased from 6745+/-2021 to 3479+/-455 microU per milliliter per minute (40.5+/-12.1 to 20.9+/-2.7 nmol per liter per minute, P=0.03), but it did not change significantly in the 25 women given placebo plus clomiphene. Nineteen of the 21 women (90 percent) who received metformin plus clomiphene ovulated (mean peak serum progesterone concentration, 23.8+/-3.4 ng per milliliter [7.6+/-10.9 nmol per liter]). Two of the 25 women (8 percent) who received placebo plus clomiphene ovulated (P<0.001). Overall, 31 of the 35 women (89 percent) treated with metformin ovulated spontaneously or in response to clomiphene, as compared with 3 of the 26 women (12 percent) treated with placebo. CONCLUSIONS: The ovulatory response to clomiphene can be increased in obese women with the polycystic ovary syndrome by decreasing insulin secretion with metformin.

Adult↗
PubMedDate not supplied

Development, pharmacology and clinical experience with clomiphene citrate.

This review describes the development and pharmacology of clomiphene and those specific characteristics of both drug and patients which determine its clinical efficacy. The studies reviewed describe clinical observation of patient characteristics (age, additional infertility diagnosis, semen quality), vaginal ultrasound observations of ovaries (number and size of pre-ovulatory follicles) and endometrial lining (thickness, pattern) in 2841 clomiphene cycles in patients who required intrauterine insemination (IUI) because of poor sperm quality or an unsatisfactory postcoital test. They show that (i) conception in clomiphene cycles is related to the number and size of pre-ovulatory follicles, endometrial thickness, patient age, pelvic adhesions, type of anovulatory disorder and semen quality; (ii) pregnancy rates per clomiphene-IUI cycle are constant through at least six cycles; (iii) multiple births cannot be prevented by withholding human chorionic gonadotrophin or advising against coitus when multiple pre-ovulation follicles are present unless all follicles down to 10-12 mm diameter are counted. We also reviewed pregnancy outcome (number of gestational sacs, babies, preclinical and clinical abortion, ectopic pregnancy and birth sex) in 1744 clomiphene pregnancies from our clinic. We found that (i) preclinical and clinical abortions are increased only slightly by clomiphene use, compared to spontaneous pregnancy; (ii) clinical abortions are decreased in patients with polycystic ovaries and luteal insufficiency who use clomiphene; (iii) conception and preclinical abortions are related to endometrial thickness prior to ovulation; (iv) ectopic pregnancies are not increased by clomiphene and (v) the ratio of male births is not altered by clomiphene, except possibly in timed insemination cycles. These studies repudiate many misconceptions regarding clomiphene. They also show that clinical outcome may be improved by pre-ovulation ultrasound monitoring of ovarian and endometrial response.

Adult↗
PubMed1983

Clomiphene citrate induces luteinizing hormone release through hypothalamic luteinizing hormone-releasing hormone in vitro.

The releasing effects of clomiphene citrate (clomiphene) on luteinizing hormone (LH) and LH-releasing hormone (LRH) were examined in a sequential double chamber superfusion system by superfusing the mediobasal hypothalami (MBH) and/or pituitaries excised from normal female rats in dioestrus. When the MBH and the pituitary were superfused in sequence with medium containing 2 X 10(-10) M oestradiol (E2), two significant peaks in LH release (60-130% increase, P less than 0.05) were observed 40 min and 90 min after the administration of 3 X 10(-8) mol clomiphene. Administration of clomiphene in medium without E2 induced a low peak (25-50% increase, P less than 0.05) of LH released from the pituitary perfused in series with the MBH. Administration of clomiphene did not cause a marked increase of LH from the pituitary superfused alone, when superfused with or without E2 containing medium. The concentration of LRH in the efflux was significantly increased (50-100%) 40 min and 90 min after clomiphene administration when MBH was superfused with medium containing E2, whereas clomiphene had no effect when superfused with medium alone. These data indicate: 1) that clomiphene induces LRH release from the MBH, that it may induce LH release, in part, by acting directly at the pituitary level; 2) that changes in LH after clomiphene administration coincide with LRH release, and 3) that a certain concentration of E2 may be necessary for the secretion of LRH by clomiphene.

Animals↗
PubMed1985

A possible role of clomiphene citrate in the control of pre-ovulatory LH surge during induction of ovulation.

A possible role of clomiphene citrate (clomiphene) in the control of ovulation in anovulatory women was investigated. Since a single ip administration of 5 micrograms oestradiol-17 beta (E2) to long-term ovariectomized rats did not induce LH surge, the following studies were designed to determine whether pretreatment with clomiphene followed by administration of E2 could induce LH surge in the ovariectomized rats. Changes in cytoplasmic and nuclear oestrogen receptors (ER) were also examined in the pituitaries of these animals. An ip injection of 200 micrograms clomiphene suppressed serum LH levels significantly for 72 h. The clomiphene injection rapidly caused an elevation of nuclear ER with a concomitant depletion of cytoplasmic ER level in the pituitary and the ER levels remained almost unchanged for 72 h. An administration of E2 12 or 24 h after the clomiphene injection had no significant effects on either the serum LH levels or the cytoplasmic and nuclear ER levels, compared with those induced by clomiphene alone. However, LH surge and the depletion of nuclear ER in the pituitary occurred 24 h later when E2 was injected 48 h after the clomiphene administration. The E2-induced LH release seems to be induced by a replacement of clomiphene by E2 on the nuclear receptor complex. These results suggest that clomiphene may exert actions directly on the pituitary gland to augment oestrogen-induced LH release.

Animals↗
PubMed1986

Inhibition of androgen and oestrogen production by clomiphene citrate in avian theca cells.

Isolated theca cells (2 X 10(5)/ml) were pre-incubated for 1 h in the presence or absence of clomiphene citrate (10(-12)-10(-4) M). Ovine LH (50 ng/ml) was added and cells were incubated for an additional 3 h. A 50% inhibition of LH-stimulated androstenedione and oestrogen production was obtained with doses of 10(-8) M and 2 X 10(-7) M clomiphene, respectively. Furthermore, the effect of clomiphene on LH-stimulated androstenedione production was reversed by washing clomiphene from the cells before stimulation with LH. In subsequent experiments, the effects of clomiphene on C17-20-lyase and aromatase activities were examined. Conversion of [3H]17-hydroxyprogesterone to androstenedione was inhibited by 50% when theca cells were pretreated with 10(-5) M-clomiphene. In addition, conversion of testosterone to oestrogen by theca cells was inhibited in a dose-dependent manner by clomiphene, with 50% inhibition occurring at a dose of 5 X 10(-6) M. The results show that clomiphene treatment in vitro inhibits androgen and oestrogen production in theca cells by inhibitory effects on the activities of C17-20-lyase and aromatase. In addition to the widely-accepted effects of clomiphene on the hypothalamic-pituitary axis, the present findings add further support to the suggestion that clomiphene exerts direct effects on ovarian steroidogenesis.

Aldehyde-Lyases↗
PubMed1996

The number of follicles and ovarian volume in the assessment of response to clomiphene citrate treatment in polycystic ovarian syndrome.

OBJECTIVE: To evaluate whether the number of follicles and ovarian volume have any significance in evaluating the response to clomiphene citrate treatment in polycystic ovarian syndrome (PCOS). DESIGN: A prospective study of 70 infertile women, 44 of which were diagnosed with polycystic ovarian syndrome. MAIN OUTCOME MEASURES: Follicle numbers and volumes in both ovaries, hormonal profile, response to Clomiphene Citrate(CC). RESULTS: Ovarian volume was significantly greater in cases with polycystic ovarian syndrome than controls. However, ovarian volume in the Clomiphene Citrate nonresponders was significantly greater than in Clomiphene Citrate responders in the polycystic ovarian syndrome group. The number of small follicles was significantly higher in cases with polycystic ovarian syndrome than controls, and in the Clomiphene Citrate nonresponder group this number was also significantly higher than in Clomiphene Citrate responders. Endocrine features of patients with polycystic ovarian syndrome revealed that Dehydroepiandrostenedione sulfate, Androstenedione, follicle stimulating and luteinizing hormone do not discriminate between patients who respond to Clomiphene Citrate and those who do not respond. However, Testosterone and luteinizing hormone levels differ significantly in responders and nonresponders. CONCLUSIONS: Small multiple follicles (> 9) and enlarged ovarian volume (> 6.8 ml) were the most prominent transvaginal ultrasonographic features of ovaries in Clomiphene Citrate nonresponsive patients with polycystic ovarian syndrome. Higher levels of Testosterone, luteinizing hormone and significantly higher number of small follicles were associated with lack of Clomiphene Citrate response. These ultrasonographic features and laboratory assays could be clinically useful for distinguishing better the Clomiphene Citrate nonresponders from responders.

Adult↗