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PubMed1983

Medroxyprogesterone, immunosuppression, and conceptus size in Peromyscus.

Effects of exogenous medroxyprogesterone acetate (MPA) on skin transplant retention and conceptus size were studied in the deer mouse, Peromyscus maniculatus, and the oldfield mouse Peromyscus polionotus. Daily injections of 2 mg MPA significantly prolonged survival of allografts in P. maniculatus and transspecific grafts between P. maniculatus and P. polionotus. Allografts were retained significantly longer than transspecific grafts (17.2 vs 12.4 days) on MPA-treated P. maniculatus. Near-term fetal and placental sizes and weights were not detectably influenced by daily 1-mg MPA injections given to the mother from the 5th through the 19th day of pregnancy. The data are discussed relative to the possible immunosuppressive role of progestins in protecting the allogeneic conceptus from maternal immune rejection.

Animals↗
PubMed2005

Characterization of medroxyprogesterone and DMBA-induced multilineage mammary tumors by gene expression profiling.

Mouse mammary tumors arising during medroxyprogesterone-DMBA-mediated mammary carcinogenesis comprised three distinct phenotypes: adenocarcinoma, squamous cell carcinoma, and myoepithelial carcinoma. The molecular signature for each of the three tumor subsets was characterized by gene microarray analysis, and three distinct sets of gene expression profiles were obtained that were corroborated in part by quantitative RT-PCR and immunohistochemistry. These results suggest that this carcinogenesis and gene expression model will be useful for rapidly assessing the histopathological differences arising in mammary carcinogenesis and the effects of tumor promoting or chemoprevention agents.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2006

Reduced metabolites mediate neuroprotective effects of progesterone in the adult rat hippocampus. The synthetic progestin medroxyprogesterone acetate (Provera) is not neuroprotective.

The ovarian hormone progesterone is neuroprotective in different experimental models of neurodegeneration. In the nervous system, progesterone is metabolized to 5alpha-dihydroprogesterone (DHP) by the enzyme 5alpha-reductase. DHP is subsequently reduced to 3alpha,5alpha-tetrahydroprogesterone (THP) by a reversible reaction catalyzed by the enzyme 3alpha-hydroxysteroid dehydrogenase. In this study we have analyzed whether progesterone metabolism is involved in the neuroprotective effect of the hormone in the hilus of the hippocampus of ovariectomized rats injected with kainic acid, an experimental model of excitotoxic cell death. Progesterone increased the levels of DHP and THP in plasma and hippocampus and prevented kainic-acid-induced neuronal loss. In contrast to progesterone, the synthetic progestin medroxyprogesterone acetate (MPA, Provera) did not increase DHP and THP levels and did not prevent kainic-acid-induced neuronal loss. The administration of the 5alpha-reductase inhibitor finasteride prevented the increase in the levels of DHP and THP in plasma and hippocampus as a result of progesterone administration and abolished the neuroprotective effect of progesterone. Both DHP and THP were neuroprotective against kainic acid. However, the administration of indomethacin, a 3alpha-hydroxysteroid dehydrogenase inhibitor, blocked the neuroprotective effect of both DHP and THP, suggesting that both metabolites are necessary for the neuroprotective effect of progesterone. In conclusion, our findings indicate that progesterone is neuroprotective against kainic acid excitotoxicity in vivo while the synthetic progestin MPA is not and suggest that progesterone metabolism to its reduced derivatives DHP and THP is necessary for the neuroprotective effect of the hormone.

3-Hydroxysteroid Dehydrogenases↗
PubMed2001

Quantitative determination of medroxyprogesterone acetate in plasma by liquid chromatography/electrospray ion trap mass spectrometry.

A sensitive and rapid liquid chromatography/electrospray ion trap mass spectrometry (LC/MS/MS) method has been developed for the quantitative determination of medroxyprogesterone acetate (MPA) in human plasma. Plasma samples (1.0 mL) were simply extracted with pentane and the extracts were analyzed by HPLC with the detection of the analyte in the selective reaction monitoring (SRM) mode. The determination of MPA was accurate and reproducible, with a limit of quantitation of 0.05 ng/mL in plasma. The standard calibration curve for MPA was linear (r = 0.998) over the concentration range 0.05-6.0 ng/mL in human plasma. Analysis precision over the concentration range of MPA was lower than 18.8% (relative standard deviation, RSD) and accuracy was between 96.2 and 108.7%.

Calibration↗
PubMed1977

Prenatal toxicity of medroxyprogesterone acetate in rabbits, rats, and mice.

Medroxyprogesterone acetate (MPA) was given once daily sc at 0.1-3,000 mg/kg/day for 3, 6, or 9 consecutive days during gestation days 7 to 15 to CD1 and A/J mice, and New Zealand (NZ) and Dutch Belted (DB) rabbits, and during days 8 to 16 to CD rats. Malformations attributable to MPA did not occur in fetuses of mice or rats exposed to the largest dosage tested. However, 1, 3, or 10 mg/kg on days 13 to 15 to NZ rabbits resulted in 6, 28, and 42% cleft palate, respectively. Comparable cleft palate frequencies were seen in DB offspring.

Abnormalities, Drug-Induced↗
PubMed1988

Medroxyprogesterone acetate therapy in early pregnancy has no apparent fetal effects.

Medroxyprogesterone acetate (MPA; Provera) was given orally to 449 women from the 5th to 7th week of pregnancy until at least the 18th week. Data are recorded from two treatment groups (recurrent abortion and threatened abortion) and are compared to a matched series. A total of 1,016 pregnancies are included in the study, and all patients were recruited from a subfertile population conceiving from a range of infertility treatments. Early pregnancy wastage was high throughout the groups and was significantly elevated (43%; P less than .001) in those women who had vaginal bleeding in early pregnancy. The study focuses on the question of potential teratogenicity of progestagens administered in the first trimester. There were 15/366 (4.1%) infants with congenital abnormalities in the MPA-treated group and 15/428 in the untreated group (3.5%). The difference was not significant, and MPA is considered to have no embryopathic risk, nor is it likely to retain an abnormal fetus that might otherwise abort. It appears that MPA is a safe drug to use in pregnancy although the question of efficacy has not been addressed in this report. Considering other recent negative epidemiologic studies with regard to teratogenicity, we add to the conclusion that MPA cannot be demonstrated to have a measurable teratogenic risk and certainly does not present a risk for congenital heart disease and limb reduction defects.

Abnormalities, Drug-Induced↗
PubMed1993

Enhanced expression of angiotensin II receptor subtypes and angiotensin converting enzyme in medroxyprogesterone-induced mouse mammary adenocarcinomas.

Angiotensin II receptors of the AT1 subtype were very highly expressed in medroxyprogesterone-induced ductal adenocarcinomas of the mammary gland in BALB/c mice. AT1 receptors are associated only to neoplastic epithelial cells. Lobular adenocarcinomas expressed very few AT1 receptors and expressed AT2 receptors only in areas corresponding to peritumoral connective tissue. Binding to angiotensin converting enzyme was present in all adenocarcinomas studied and was higher in ductal than in lobular adenocarcinomas. Normal mammary gland did not express either angiotensin II receptors or angiotensin converting enzyme. The present results are the first demonstration of angiotensin receptor subtypes and converting enzyme in mammary adenocarcinomas differentially expressed in tumors of ductal and lobular origin. Localization of receptor subtypes could be useful to study the differentiation of mammary cells during experimental mammary carcinogenesis in mice.

Adenocarcinoma↗
PubMed1995

Cisplatin, adriamycin, etoposide, megestrol acetate versus melphalan, 5-fluorouracil, medroxyprogesterone acetate in the treatment of endometrial carcinoma.

Fifty consecutive patients with documented advanced or recurrent endometrial carcinoma from 1978 through 1985 were prospectively treated with melphalan, 5-fluorouracil, medroxyprogesterone acetate (MFP) as first-line chemotherapy. From 1987 through 1993, 50 consecutive patients with documented advanced or recurrent endometrial carcinoma were prospectively treated with cisplatin, Adriamycin, etoposide, megestrol acetate (PAV-M) as first-line chemotherapy. Response rates for MFP versus PAV-M, 2- and 5-year survival, median survival, 2- and 5-year progression-free survival, and median progression-free survival were not statistically different. However, there was a significant improvement favoring PAV-M in 2-year (45 versus 14%), 5-year (30 versus 5%), and median survival (22.3 versus 8.7 months) (P = 0.008) compared to MFP in patients with primary advanced endometrial adenocarcinoma. Moreover, there was a significant improvement in 2- and 5-year and median survival (55 and 15% and 26.7 months) for PAV-M compared to MFP (7 and 0% and 7.3 months) (P = 0.002) for the more aggressive other adenocarcinomas (adenosquamous, clear cell, papillary serous, undifferentiated) compared to the more common endometrioid adenocarcinoma. The current data suggest that cisplatin- and adriamycin-based chemotherapy results in some long-term survival benefit for patients with primary advanced endometrial adenocarcinoma and the more aggressive nonendometrioid adenocarcinoma histologies.

Aged↗
PubMed1996

Vascular endothelial growth factor expression is not regulated by estradiol or medroxyprogesterone acetate in endometrial carcinoma.

OBJECTIVE: To determine whether the expression of vascular endothelial growth factor (VEGF) is altered by treatment in an in vivo tumor with 17 beta-estradiol (E2) or medroxyprogesterone acetate (MPA). METHODS: A well-differentiated endometrial carcinoma tumor was isolated from a patient and explanted into the dorsal skin of ovariectomized nude mice, from which it was serially passaged in vivo. The explanted tumor retained all the properties of the original tumor, including estrogen and progesterone receptor expression and growth promotion and inhibition by E2 and MPA, respectively. The mice were treated with continuous E2 administration followed by treatment with either a single intramuscular administration of 2 mg MPA or weekly administrations of 2 mg MPA. Untreated tumor-bearing mice served as controls. The tumors were harvested at 0 to 21 days from first MPA administration. RNA from the tumors was isolated and VEGF expression was determined by Northern analysis. RESULTS: VEGF was expressed in the absence of treatment with E2 or MPA, and expression was unaltered by continuous treatment with E2. Additional treatment with a single does of MPA did not alter expression at Days 1, 2, 3, 7, 14, and 21, and additional treatment with E2 or E2 + MPA. Regulation of VEGF expression is not a mechanism by which these hormones exert their growth effects on endometrial tumors.

Actins↗
PubMed2000

Endometrial carcinoma remaining after term pregnancy following conservative treatment with medroxyprogesterone acetate.

BACKGROUND: Successful pregnancies after conservative progestin treatment to young women with endometrial carcinoma have recently been reported. However, it is not known for certain whether the lesion is completely eradicated in such patients. We present a case of residual endometrial carcinoma after term pregnancy which had been treated conservatively before the pregnancy began. CASE: A 28-year-old woman with endometrial carcinoma received conservative treatment with high-dose medroxyprogesterone acetate (MPA) and then conceived. After delivery at term, atypical cells were found in the endometrial curettage specimen. A hysterectomy was performed 6 months after delivery and revealed the presence of a small focus of intramucosal, grade 1, endometrioid-type adenocarcinoma. Immunohistochemically, the tumor cells were positive for estrogen and progesterone receptors. CONCLUSION: We concluded that while MPA treatment had been effective, it had not completely eradicated the carcinomatous lesion, which remained during and after the term pregnancy.

Adenocarcinoma↗
PubMed2002

A pilot study of ovarian cancer chemoprevention using medroxyprogesterone acetate in an avian model of spontaneous ovarian carcinogenesis.

OBJECTIVE: Our previous studies have documented the feasibility of using the laying hen, Gallus domesticus, as a model of spontaneous ovarian carcinogenesis. This study was performed to determine the ability of medroxyprogesterone acetate (Depo-Provera) to reduce the frequency of spontaneously developing reproductive tract adenocarcinoma in the avian model. METHOD: Four hundred 3-year-old hens were in a two-arm trial designed to determine the frequency of epithelial reproductive tract adenocarcinomas. Animals were designated to receive three injections of 100 mg Depo-Provera versus no injection over a 16-month period. Both groups were subjected to two induced molts 12 months apart. Egg counts were obtained and decreased egg production was documented in the treated hens due to Depo-Provera. At the end of 16 months surviving animals were sacrificed and the frequency of reproductive tract adenocarcinoma was determined histologicically. RESULTS: Histologic information was obtained from the 293 hens that completed the full prescribed course of study. At the time of necropsy, multiple hens had evidence of carcinomatosis and massive ascites consistent with metastatic reproductive tract adenocarcinomas. Of the tissues examined from the informative cases gathered at the time of sacrifice, there was evidence of a reduction of reproductive tract adenocarcinoma observed in the Depo-Provera group (45/127-35%) when compared to the control group (69/166-42%). A risk reduction of 15% is observed in the treatment group (risk ratio 0.85: 95% confidence interval 0.63-1.15). CONCLUSION: The high rate of reproductive tract adenocarcinoma observed in this study supports the avian hen as a valid model of spontaneous ovarian carcinogenesis in which to test chemoprevention strategies and provides a unique opportunity for investigating the pathogenesis of ovarian carcinoma. The current histologic findings are consistent with the theory that a reduction of ovulatory events may prevent the development of ovarian adenocarcinoma.

Adenocarcinoma↗
PubMed1979

The use of medroxyprogesterone acetate to study progestin receptors in immature, pregnant, and adult rabbit uterus.

Medroxyprogesterone acetate (MPA)3, a potent synthetic progestin, was employed as the 3H-ligand to investigate the status of the rabbit uterine progestin receptor under various hormonal conditions. MPA dissociated slowly from the cytosol and nuclear progestin receptor obtained from ovariectomized, estrogen-primed rabbits. This slow rate of dissociation permitted a partial characterization of the receptors in pregnant and immature, unprimed rabbit uteri. High affinity progestin binding to 6--7 S and 4 S macromolecular species was detected in cytosol and nuclear extracts, respectively, from these animals. In contrast to the 3 peaks of cytosol receptor activity from estrogen-primed animals which were eluted stepwise from DEAE-cellulose columns, predominantly 2 peaks were obtained with cytosols from pregnant and immature, unprimed uteri. Further studies are required to determine to what extent progestin action is modified through interaction of these binding components with themselves and other cellular proteins.

Aging↗
PubMed1980

Comparative pharmacokinetics of medroxyprogesterone acetate administered by oral and intramuscular routes.

The present study was undertaken to elucidate (1) the relationship between plasma concentration of medroxyprogesterone acetate (MPA; Clinovir) administered by the PO and the IM routes; and (2) the relationship between dose and plasma concentration of MPA. Nineteen patients entered the study. In each patient the plasma concentration was monitored after a single PO and IM administration of MPA at the following dose levels: 100 mg (5 patients), 400 mg (5 patients), 800 mg (5 patients) and 1,200 mg (4 patients). The time interval between PO and the IM administration was 1 week. The results show (1) a very large interindividual variation in plasma concentration; (2) increasing plasma concentration with both PO and IM dose; (3) after the IM administration plasma levels are steady or increase slightly within the test period; (4) after the oral administration the concentration increases rapidly to reach a peak before 2-7 h and subsequently decreases again, peak concentrations being 2-10 times higher than after IM administration; and (5) within the test periods the plasma concentration x time (0-168 h) is comparable with the two methods of administration.

Administration, Oral↗
PubMed1995

Effects of medroxyprogesterone acetate therapy on advanced or recurrent breast cancer and its influences on blood coagulation and the fibrinolytic system.

The effects of medroxyprogesterone acetate (MPA) therapy on advanced or recurrent breast cancer and its influence on blood coagulation and the fibrinolytic system were compared among three different therapy regimens consisting of cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) + MPA and CAF or MPA alone. A clinical response was observed in 42.9% (9/21) of the patients for CAF + MPA, 36.4% (8/22) for CAF and 23.8% (5/21) for MPA alone. No marked thrombosis or its prodromal condition was observed in any group. The effects on the test values for blood coagulation and the fibrinolytic system did not significantly change in the CAF group. However, both AT-III and protein C significantly increased above the normal ranges in the CAF+MPA and MPA groups. Increases in factor X, plasminogen, and alpha 2-plasmin inhibitor/plasmin complex (PIC) and decreases in fibrinogen, tissue plasminogen activator, and D-dimer, were all observed in the MPA and CAF + MPA groups, especially in the MPA group, although these changes remained within the normal ranges. The data indicated that MPA has various influences on blood coagulation and the fibrinolytic system, but these changes did not suggest activation of the blood coagulation system.

Antineoplastic Agents, Hormonal↗
PubMed1996

The effectiveness of medroxyprogesterone in the treatment of multiple metastasizing leiomyosarcomas: report of a case.

A 51-year-old woman was admitted to our hospital for further investigation of chest X-ray films which showed multiple shadows that had been growing slowly over 2 years. Her only symptom was hemosputa. The lesions were suspected of being metastasizing leiomyoma due to her past history of uterine leiomyoma. Just 1 week before undergoing scheduled open lung biopsy, the lung lesions increased remarkably in size and number. A thoracotomy was performed and six of the numerous nodules were removed. The resected specimens were pathologically diagnosed as metastasizing leimyosarcoma which was positive for the progesterone and estrogen receptors. Thus, 1 month postoperatively, a course of medroxyprogesterone (MPA), 600 mg daily, was commenced. The residual lesions in her chest started to diminish, shortly afterward. She has remained well on this MPA regimen for 45 months. The prognosis of patients with metastasizing leiomyosarcoma is poor because of its low sensitivity to chemotherapy; however, some types of leiomyosarcoma are hormone-sensitive. It is therefore important to examine the hormone receptors of excised tumors from patients suspected of having metastasizing leiomyoma or leimyosarcoma.

Antineoplastic Agents, Hormonal↗
PubMed1995

Inhibitory effects of medroxyprogesterone acetate (MPA) and the pure antiestrogen EM-219 on estrone (E1)-stimulated growth of dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat.

Estrogens are well known to play a predominant role in promoting the growth of DMBA-induced mammary tumors in the rat. Estrone (E1), a steroid having weak estrogenic activity, is one of most important estrogens in post-menopausal women, where it is converted into the potent estrogen estradiol (E2) by 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) in many peripheral tissues, including the mammary gland. In this report, we have studied the effect of a new antiestrogen (EM-219) (N-butyl, N-methyl-11-(3', 17'beta-dihydroxy-17'alpha-ethinyl-estra-1'3'5'(10'), 14'-tetraen-7'alpha-yl) undecanamide) on E1-stimulated growth of DMBA-induced mammary tumors and compared its effect with that of medroxyprogesterone acetate (MPA) alone or in combination. After 18 days, ovariectomy (OVX) reduced total tumor area to 29.6 +/- 7.1% of the original size, while E1 (1.0 microgram, twice daily) caused a 139 +/- 21% increase in tumor size in OVX animals. MPA (1.5 mg, twice daily) partially reversed the stimulatory effect of E1 to 66.0 +/- 9.0%, while the antiestrogen EM-219 (40 micrograms, twice daily) decreased tumor size to 70.0 +/- 10%. Combination of these two compounds led to a further inhibition of tumor size to 30.7 +/- 7.4% of the value found in OVX animals treated with E1. Tumor E2 levels decreased from 1688 +/- 155 pmoles/kg tissue in OVX animals receiving E1 to 709 +/- 92, 1347 +/- 98, and 184 +/- 11 pmoles/kg tissue in MPA-, EM-219-, and MPA+EM-219-treated OVX-E1 animals, respectively. Treatment of OVX animals with E1 increased by 69% the reductive activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) while MPA abolished completely this effect of E1. In the oxidative direction, treatment with E1, E1 + MPA, or E1 + EM-219 had minimal or no significant effect on the activity of 17 beta-HSD (vs OVX), while the combined treatment with MPA+EM-219 induced a 2-fold increase in 17 beta-HSD activity, thus leading to an increased conversion of E2 into E1. The present data show that combination of the pure antiestrogen EM-219 with MPA exerts a greater reduction in DMBA-induced mammary tumor growth and intratumoral E2 levels stimulated by E1 than either compound used alone. This interactive effect of the antiestrogen and MPA could at least partially be related to the increased inactivation of E2 into E1.(ABSTRACT TRUNCATED AT 400 WORDS)

17-Hydroxysteroid Dehydrogenases↗
PubMed1993

Controlled release low dose medroxyprogesterone acetate (MPA) inhibits the development of mammary tumors induced by dimethyl-benz(a) anthracene in the rat.

Medroxyprogesterone acetate (MPA) is well recognized to have beneficial effects for the treatment of advanced breast cancer which are comparable to those achieved with other forms of endocrine therapy. Using mammary tumors induced in the rat by dimethylbenz(a)anthracene (DMBA) as a model, we have studied the possibility that low dose MPA could prevent the development of these tumors. Single subcutaneous injection of Depo-Provera (crystalline suspension of MPA) or MPA encapsulated in biodegradable microspheres of 50:50 poly[DL-lactide-co-glycolide] was given 7 days before oral DMBA. While 63% of intact animals developed palpable mammary tumors within 85 days after DMBA administration, tumor incidence decreased to 28% and 23% in animals who had received 30 mg and 100 mg of Depo-Provera, respectively. The same amounts of MPA delivered in microspheres caused a further decrease in tumor incidence to respective values of 7% and 6%. Average tumor area, on the other hand, decreased from 4.89 cm2 in intact rats to about 0.75 (0.57-0.88) cm2 and approximately 0.20 (0.14-0.22) cm2 in the Depo-Provera and microsphere-treated groups, respectively. Using the 50:50 formulation of poly[DL-lactide-co-glycolide] designed to release MPA at a constant rate for a 4-month period, the serum MPA concentration at 3 months was measured at 4.99 +/- 0.43 ng/ml. Such data suggest that administration of a low dose controlled-release formulation of MPA in 50:50 poly[DL-lactide-co-glycolide] microspheres could well be an efficient and well tolerated approach for the prevention of breast cancer in women.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Effect of medroxyprogesterone acetate (MPA) and serum factors on cell proliferation in primary cultures of an MPA-induced mammary adenocarcinoma.

The effect of progesterone (Pg), medroxyprogesterone acetate (MPA), estradiol (E2), dihydrotestosterone (DHT) and dexamethasone (DEXA) was studied on the in vitro growth rate of a progestin-dependent (PD), estrogen-sensitive mammary tumor line originated in an MPA-treated BALB/c mouse (C4-HD), and on its estrogen-resistant variant (C4-HDR). The specificity of hormone action was further investigated using the anti-hormones RU-486 and hydroxyflutamide (FLU). Cell growth was evaluated in epithelial and fibroblast-enriched cultures using 3H-thymidine and/or autoradiography and immunocytochemistry. The results indicate that cell growth is directly stimulated by MPA and Pg at concentrations ranging from 10(-11) to 10(-7) M. RU486 prevented MPA-induced stimulation in concentrations 10 to 100 fold lower than those of MPA. When used alone, it inhibited cell proliferation only in concentrations higher than 10(-11) M. At nM concentrations, neither DEXA nor DHT stimulated 3H-thymidine uptake except DEXA at 100 nM. MPA-induced stimulation was not reverted by micromolar concentrations of FLU. As for E2 (10(-7)-10(-9) M) it prevented MPA stimulation only in cultures of estrogen-sensitive tumors. Progesterone receptors (PR) (475 +/- 115 fmoles/10(5) cells, n = 5) and estrogen receptors (ER) (ND-115 fmoles/10(5) cells, n = 5) were detected only in epithelial-enriched cultures. Serum from 7 day-MPA-treated mice induced a significant increase of 3H-thymidine uptake; an increase was also obtained with serum from untreated ovariectomized animals to which 1 nM-100 nM concentrations of MPA had been added. The stimulatory effect of the exogenous MPA was much lower than that of the serum obtained from MPA-treated animals. It is concluded that MPA stimulates cell growth of primary cultures of MPA-induced PD tumors via PR. The results provide support for a direct effect of MPA which may be mediated or potentiated by serum factors.

Adenocarcinoma↗