Growth stimulation of a rat pituitary cell line MtT/E-2 by environmental estrogens in vitro and in vivo.
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Endocrine disruptors are a diverse group of chemicals that alter the functions of the endocrine system. A large proportion of endocrine disruptors have estrogenic effects, thus are called environmental estrogens. In the present study, an estrogen (E2) responsive rat pituitary cell line, MtT/E-2, was employed to examine 1) the potency of several endocrine disruptors including bisphenol A (BPA), o,p'-DDD, methoxychlor, 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and dibromoacetic acid (DBAA) in terms of E2 responsive pituitary cell growth; 2) whether BPA has estrogenic action in vivo causing the growth of MtT/E-2 cells grafted in rats. Binding assays showed the test chemicals were able to compete with 3H-E2 binding to the estrogen receptor (ER). The compounds also stimulated growth of MtT/E-2 cells at rates corresponding to their ER binding affinity. Their transcription activation of an (ERE)3-SV40-luciferase reporter in MtT/E-2 cells was comparable to their stimulation of cell growth, with the exception of HCH which showed little induction of cell growth but strong stimulation in ERE dependent transcription activation. MtT/E-2 cells were inoculated into ovariectomized female F344 rats treated with E2 or BPA. The first tumors were noted at day 22 in the E2 treated group, at day 25 in the highest dose of BPA group and at day 41 in the control group. These results suggest 1) that the growth assay with MtT/E-2 cells provides simple and sensitive test for detection of estrogenic activity of environmental chemicals; 2) that BPA has estrogenic potency to stimulate E2 responsive cell growth in vivo as well as in vitro. (+info)
Adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia treated with mitotane.
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We report a case of adrenocorticotropic hormone (ACTH)-independent bilateral macronodular adrenocortical hyperplasia (AIMAH), which was successfully treated with mitotane. A 71-year-old man visited our hospital because of central obesity and enlarged bilateral adrenal glands. The endocrinological studies showed elevated plasma cortisol and undetectable levels of ACTH, a lack of suppression with high-dose dexamethasone and a hyper-response to exogenous ACTH. These clinical features were compatible with the diagnosis of AIMAH. In this patient, extra-adrenal multiple tumors were also detected. After treatment with mitotane, the plasma level of cortisol was decreased while that of ACTH was increased and the signs of Cushing's syndrome were resolved. (+info)
Salmonid sexual development is not consistently altered by embryonic exposure to endocrine-active chemicals.
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Fish sexual development is sensitive to exogenous hormone manipulation, and salmonids have been used extensively as environmental sentinels and models for biomedical research. We simulated maternal transfer of contaminants by microinjecting rainbow trout (Oncorhynchus mykiss) and chinook salmon (Oncorhynchus tshawytscha) embryos. Fish were reared for 6 months and sexed, and gonads were removed for histology and measurement of in vitro steroid production. Analysis of fat samples showed that dichlorodiphenylethylene (DDE) levels, o, p'M-DDE and p,o, p'-DDE isomers, were elevated 6 months after treatment. A preliminary study showed an increased ratio of males to females after treatment with 80 mg/kg and 160 mg/kg of the xenoestrogen o,o, p'-DDE. One fish treated with 160 mg/kg o,o, p'-DDE had gonads with cells typical of both males and females. A follow-up study, using more fish and excluding the highly toxic 160 mg/kg o,o, p'-DDE dose, showed no effect on sex ratio or gonadal histology. Embryonic exposure of monosex male trout, monosex female trout, and mixed sex salmon to o, o, p'-DDE, p,o, p'-DDE, mixtures of DDE isomers, and octylphenol failed to alter sexual development. We observed no treatment-dependent changes in in vitro gonadal steroid production in any experiments. Trout exposed in ovo and reared to maturity spawned successfully. These results suggest that mortality attributable to the xenoestrogens o,o, p'-DDE, chlordecone, and octylphenol, and the antiandrogen p,o, p'-DDE, is likely to occur before the appearance of subtle changes in sexual development. Because trout appeared to be sensitive to endocrine disruption, we cannot dismiss the threat of heavily contaminated sites or complex mixtures to normal sexual development of salmonids or other aquatic organisms. (+info)
Changes in neoplastic cell features and sensitivity to mitotane during mitotane-induced remission in a patient with recurrent, metastatic adrenocortical carcinoma.
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A 58-year-old man had adrenocortical carcinoma in the right adrenal gland. The tumour secreted excessive cortisol and dehydroepiandrosterone-sulphate (DHEA-S), and had invaded the right hepatic lobe and vena cava. Eleven months after surgical tumour resection, the serum DHEA-S levels again increased. Local tumour recurrence and a metastasis was found in the lung. Eleven months after surgery chemotherapy with mitotane (o,p'-DDD) was initiated. Twelve weeks of mitotane reduced serum DHEA-S levels and caused these tumours to disappear. The patient was then treated with low-dose mitotane (1.5-2.0 g/day) for 2 years. Serum levels of mitotane remained at less than 10 microg/ml. Although such low serum levels of mitotane and delayed initiation of mitotane after surgery have been proposed to weaken the antineoplastic effect of mitotane, the patient had a remission for 2 years. However, there was then local re-recurrence with an increase in serum DHEA-S and death 4 months later. The histological features of neoplastic cells were quite different comparing tumour resected at surgery and tumour at autopsy. The latter had more frequent mitotic nuclei. This tumour was initially sensitive to mitotane, but later became insensitive. (+info)
A case of renin-producing adrenocortical cancer.
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Here we report a case of a renin-producing adrenocortical carcinoma. A 57-year-old woman was referred to our hospital complaining of thirst and generalized muscle weakness. She was diagnosed as being hypertensive and diabetic with associated hypokalemia and she had a hard elastic mass with a diameter of 10 cm on the left side of her neck. An abdominal computed tomography scan revealed a suprarenal mass on the left side (8.5 x 8 x 6.5 cm). Endocrinological examination demonstrated a marked elevation in the patient's serum glucocorticoid and sex steroid hormones as well as plasma renin activity. Histological examination of a sample taken from the neck mass revealed a metastasis from an adrenal carcinoma, which was stained positively with antibodies against cytochrome P450 and renin, establishing the diagnosis of a renin-producing adrenocortical carcinoma. Trilostane was effective in reducing serum cortisol levels, but mitotane was ineffective. (+info)
Clinical results of the use of mitotane for adrenocortical carcinoma.
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Mitotane (o,p'-DDD) acts mainly as an inhibitor of intramitochondrial pregnenolone and cortisol synthesis. Its adrenolytic effect depends on metabolic activation due to conversion to o,p'-DDA and o,p'-DDE. The drug has been used for 40 years in the treatment of adrenocortical carcinoma, mainly its regional and metastatic stage, as an adjuvant to surgical resection of the tumor. In the medical literature there are controversial opinions about its efficacy for the treatment of adrenocortical carcinoma. In our experience, mitotane administered immediately after surgery appeared to be much more efficient than when administered later. We have administered this drug in all cases of microscopically confirmed adrenocortical carcinoma, irrespectively of stage at the time of surgery, for fear of a false too optimistic classification. In our series of 82 patients with adrenocortical carcinoma, 59 patients have been treated with mitotane, 32 of them immediately after surgery, and 27 with a delay of 2 to 24 months. Today there are 18 survivors in the group of patients treated with mitotane soon after the operation and only 6 survivors in the group receiving mitotane with a delay. All patients were simultaneously given replacement therapy. Undesired effects of mitotane administration included increased aminotransferase and alkaline phosphatase activity, decreased white cell, platelet or red cell number, and myasthenia. Furthermore, we used mitotane with good results in Cushing's syndrome of non-malignant origin as pre-treatment before surgery or in long-term treatment for patients with poor tolerance of other adrenal inhibitors. (+info)
Conventional and novel strategies in the treatment of adrenocortical cancer.
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Adrenocortical carcinoma is a highly malignant neoplasm with an incidence of two per million people per year. Several treatment strategies have resulted in temporary or partial tumor regression but very few cases have attained long survival. Surgical resection of the primary tumor and metastases is most effective. Several chemotherapeutic protocols have been employed with variable success. Mitotane (o,p'-DDD) is an adrenalytic drug effective in inducing a tumor response in 33% of patients treated. Mitotane requires metabolic transformation for therapeutic action. Tumors may vary in their ability to metabolize mitotane and the ability of tumors to transform mitotane may predict the clinical response to the drug. Preliminary data show a possible correlation between metabolic activity of neoplastic adrenocortical tissue and response to mitotane. We have attempted to develop mitotane analogs with enhanced adrenalytic effect. Compared to mitotane, a di-chloro compound, the bromo-chloro and di-bromo analogs appear to have a greater effect. Future approaches to the treatment of adrenocortical carcinoma are likely to be based on blocking or reversing the biological mechanisms of tumorigenesis. Angiogenic and chemotactic mechanisms may play a role in adrenal tumor growth and inhibition of these mechanisms may result in inhibition of tumor growth. New mitotane analogs with greater adrenalytic potential could be a promising approach to developing more effective and selective therapies for adrenal cancer. Alternative approaches should attempt to suppress tumor growth by means of compounds with anti-angiogenic and anti-chemotactic activity. (+info)
Streptozocin and o,p'DDD in the treatment of adrenocortical cancer patients: long-term survival in its adjuvant use.
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BACKGROUND: To evaluate the efficacy of streptozocin and o.p'DDD (SO) in adrenocortical cancer (ACC) patients since other chemotherapeutic regimens have limited effects. PATIENTS AND METHODS: We performed a phase II study with SO therapy in 40 ACC patients (median age 44 years). Oral o,p'DDD administration (1-4 g/d, every day) was given together with intravenous streptozocin (1 g/d for five days, thereafter 2 g once every three weeks). 5HT3-receptor blocker was used as standard premedication for streptozocin. RESULTS: The SO therapy was found to have significant effects on disease-free interval (P = 0.02) as well as on survival (P = 0.01) in adjuvantly treated cases (n = 17) in comparison to the patients who did not get any therapy after complete resection (n = 11). Complete or partial response was obtained in 36.4% of patients with measurable disease (n = 22). The overall two-year and five-year survival rates were 70% and 32.5%, respectively. The presence of metastases at diagnosis was identified as a poor prognostic factor (P = 0.02). CONCLUSIONS: The present study necessitates further randomized clinical study of SO therapy in the treatment of ACC, mainly as adjuvant treatment immediately after curative intended surgery, and could be developed into a regular treatment regimen. (+info)