A comparison of the effects of tributyltin chloride and triphenyltin chloride on cell proliferation, proapoptotic p53, Bax, and antiapoptotic Bcl-2 protein levels in human breast cancer MCF-7 cell line.

In recent years it was disclosed, that numerous organotin(IV) derivatives have remarkable cytotoxicity against several types of cancer cells. The property to inhibit cell growth makes these compounds promising for antitumor therapy, as the clinical effectiveness of cisplatin is limited by drug resistance and significant side effects. Tributyltin and triphenyltin are known as endocrine disruptors. Moreover, the compounds exert their toxicity in mammals predominantly through nuclear receptor signaling. Here we present the effects of tributyltin chloride (TBT-Cl) and triphenyltin chloride (TPT-Cl) on cell proliferation, expression of proapoptotic p53, Bax, and antiapoptotic Bcl-2 proteins in human breast cancer MCF-7 cell line. Dose and time dependent (24, 48 and 72 h) cell expositions have demonstrated TBT-Cl as more effective in inhibiting MCF-7 cell proliferation than TPT-Cl. Short time treatment with TBT-Cl displayed marked stimulation of p53 protein expression when compared to TPT-Cl. Both organotin compounds displayed similar mild enhancement of Bax protein expression. The 24h exposition of TPT-Cl induced substantial diminution of Bcl-2 protein expression in comparison with both, untreated cells and TBT-Cl treated cells. Our observations indicate that TBT-Cl and TPT-Cl have different antiproliferative potency and distinct impact on expression of apoptosis marker proteins.

Lower adrenocortical and adrenomedullary responses to hypoglycemia in premenopausal women with systemic sclerosis.

OBJECTIVES: To evaluate function of the hypothalamic-pituitary-adrenal (HPA) axis, adrenomedullary hormonal system (AMHS), and sympathetic noradrenergic system (SNS) in premenopausal women with systemic sclerosis (SSc). METHODS: Insulin-induced hypoglycemia (0.1 IU/kg) was performed in 17 longterm, glucocorticoid-naive SSc patients with low disease activity and in 18 healthy women matched for age and body mass index (BMI). Concentrations of glucose, adrenocorticotrophic hormone (ACTH), cortisol, androstenedione (ASD), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), 17a-hydroxyprogesterone (17OHP), epinephrine (EPI), norepinephrine (NE), interleukin 1ss (IL-1ss), IL-6, and tumor necrosis factor-a (TNF-a) were analyzed in plasma. RESULTS: Basal plasma levels of cortisol, ASD, 17OHP, DHEAS, IL-1ss, IL-6, and TNF-a were not significantly different in SSc compared to controls. Patients had higher basal ACTH (6.76 +/- 1.0 pmol/l in SSc vs 4.14 +/- 0.45 pmol/l in controls; p < 0.05), lower basal DHEA (9.02 +/- 1.64 nmol/l in SSc vs 17.0 +/- 2.8 nmol/l in controls; p < 0.05), and lower basal NE (1.61 +/- 0.26 nmol/l in SSc vs 2.57 +/- 0.38 nmol/l in controls; p < 0.05). Patients had comparable responses of glucose and ACTH to hypoglycemia. General linear model for repeated measurements, with BMI and age as covariates, revealed that the responses of 17OHP (p < 0.05), ASD (p < 0.05), DHEA (p < 0.01), EPI (p < 0.001), and NE (p < 0.001) to hypoglycemia were lower in SSc compared to controls. Cortisol response to hypoglycemia tended to be lower in SSc patients (p = 0.06) compared to controls. CONCLUSION: Our data indicate decreased adrenocortical and adrenomedullary functions in premenopausal women with SSc. Whether the observed changes in the neuroendocrine system are secondary to chronic disease deserves further investigation.

Comparison of hormone transfer to pleural and synovial exudates.

OBJECTIVES: Local effects of hormones on immune and connective tissues could play some role in the development of local inflammation processes. The aim of this study was to investigate the levels of selected hormones in pleural exudates of patients with pleurisy and lung tumours, and compare these levels with hormone concentration in knee synovial fluid. SUBJECTS AND METHODS: Eleven patients with pleural exudate (mean age 62+/-3) and l9 subjects with rheumatoid arthritis (of the same mean age) participated in the observations. Plasma, pleural exudates and synovial fluid levels of cortisol, prolactin, aldosterone, testosterone, 17-beta-estradiol, dehydroepiandrosterone, progesterone, insulin and C-peptide were determined by specific radioimmunoassay. RESULTS: It was noted that all estimated hormones are transferred into pleural exudates and synovial fluid. Higher levels of dehydroepiandrosterone and C-peptide were observed in pleural exudates as compared to plasma. The concentrations of testosterone, prolactin and estradiol in males were lower in exudates as compared to plasma. Mean levels of cortisol, aldosterone, progesterone and insulin in plasma were similar to these found in pleural exudates. The comparison of hormone levels in pleural exudates and synovial fluid showed that the levels of cortisol, progesterone and dehydroepiandrosterone tended to be higher in the exudates as compared to synovial fluid. However, the levels of insulin, testosterone and estradiol in exudates were lower than these in inflammatory synovial fluid from patients with rheumatoid arthritis. CONCLUSIONS: This study showed the presence of hormones in pleural exudates. The differences in hormone concentrations in pleural exudates and synovial fluid were observed suggesting a specificity of hormone transfer from plasma to these exudates.

Prolactin and growth hormone responses to hypoglycemia in patients with systemic sclerosis and psoriatic arthritis.

This study compared prolactin (PRL) and growth hormone (GH) responses to hypoglycemia in premenopausal females with systemic sclerosis (SSc) and psoriatic arthritis (PsA) with those in matched healthy controls. No differences were found in glucose and GH responses to hypoglycemia in both groups of patients compared to controls. SSc patients had lower PRL response (P < 0.05) to hypoglycemia compared to controls. PRL response tended to be lower also in PsA patients, however the difference did not reach level of statistical significance (P = 0.11). The present study showed decreased PRL response to hypoglycemia in premenopausal females with SSc.

MNU-induced carcinogenesis of rat mammary gland: effect of thyroid hormone on expression of retinoic acid receptors in tumours of mammary gland.

The rat model of N-methyl-N-nitrosourea (MNU)-induced mammary carcinomas is well-established animal model for breast cancer. This study was carried out to investigate whether hypothyroid (thyroidectomy or PTU treatment) or hyperthyroid status of female rats would affect MNU-induced mammary carcinogenesis with specific focus on both retinoid and rexinoid receptor expression in mammary tumours. Application of PTU before and during MNU-induced mammary gland carcinogenesis yielded in a marked decrease of the number and volume of tumours per animal, however, there was no effect of hypothyroid state in thyroidectomized rats as well as hyperthyroid state concerning the number and volume of tumours. Mammary tumours of in euthyroid group of MNU animals showed that there was no tumour, in which all of subtypes of retinoid and rexinoid receptors were expressed. A different pattern of expression of retinoid or rexinoid receptors was found either in MNU-induced mammary carcinomas in both hypothyroid and hyperthyroid rats.

Prolactin and growth hormone responses to hypoglycemia in patients with rheumatoid arthritis and ankylosing spondylitis.

OBJECTIVE: Prolactin (PRL) and growth hormone (GH) are pituitary hormones with immunomodulating properties. Their upregulated secretion may play a role in the pathogenesis of chronic inflammatory diseases. We evaluated PRL and GH responses to secretion stimulus in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). METHODS: Insulin hypoglycemia (0.1 IU/kg) was induced in 15 women with RA, 18 men with AS, and healthy controls matched for age, sex and body mass index. Plasma concentrations of glucose, PRL, GH, interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-a) were analyzed. RESULTS: RA patients had significantly lower area under the curve (AUC) of PRL (p = 0.049) compared to RA controls. During hypoglycemia double or higher increase of plasma PRL occurred in 5 RA (33%) patients and in 8 RA controls (57%). Using the General Linear Model procedure, no significant differences in PRL or GH responses were observed in patients with RA and AS. TNF-a was higher in patients with RA compared to RA controls (p < 0.05). There was no significant difference in TNF-a concentrations between AS patients and AS controls. IL-6 was higher in RA patients compared to controls (p < 0.05) and in AS patients compared to controls (p < 0.01). Significant positive correlation was found between TNF-a levels and AUC of PRL in AS patients (r = 0.46, p = 0.047), but not in the 2 control groups or in RA patients. CONCLUSION: Our results indicate no upregulated PRL or GH responses to stimulation in premenopausal women with RA or men with AS.

Effects of real and simulated microgravity on response of sympathoadrenal system to various stress stimuli.

Changes in plasma levels of epinephrine (EPI) and norepinephrine (NE) were investigated in humans exposed to physical exercise (WL), to psychic stressor (mental arithmetic test, MAT), and to oral glucose administration (oGTT) before and during a stay in microgravity (real space flight, SF) or in simulated microgravity (head-down bed rest, HDBR). A permanent cannula inserted into the cubital vein and a special appliance, Plasma-03, were used for blood collection, plasma separation, and freezing of samples during SF. Plasma EPI, NE, dihydroxyphenylglycol (DHPG), and dihydroxyphenylalanine (DOPA) levels were measured by the high-pressure liquid chromatography (HPLC) method. Basal plasma EPI, NE, DHPG, and DOPA levels were found within the range of control values during SF. Preflight WL produced high increase in plasma NE and moderate elevation of plasma EPI, DHPG, and DOPA levels. Exaggerated exercise induced increases in plasma NE, DHPG, EPI, and DOPA levels were demonstrated in real microgravity. A return to preflight responses of sympathoadrenal system was seen after the landing. Plasma EPI, NE, and DHPG responses to MAT were relatively small, but increased during SF. During the oGTT the plasma EPI levels were slightly reduced in microgravity. Similarly as in SF, WL in HDBR was followed by significantly exaggerated responses of plasma catecholamines. These results show that both somatic and psychological stressors are able to induce an increased activation of sympathoadrenal system during SF or simulated microgravity in HDBR.

Effects of space flight and -6 degrees bed rest on the neuroendocrine response to metabolic stress in physically fit subjects.

The aim of this study was to evaluate the association of plasma epinephrine (EPI) and norepinephrine (NE) responses to insulin-induced hypoglycemia (ITT) 3 weeks before the space flight (SF), on the fifth day of SF, on days 2 and 16 after landing in the first Slovak astronaut, and before and on the fifth day of prolonged bed rest (BR) in 15 military aircraft pilots, aged 33.5 +/- 1.4 years, body mass index (BMI) 26.5 +/- 0.7 kg/m(2), maximal oxygen uptake (VO(2max)) 55.2 +/- 2.4 mL/kg/min, who volunteered for the study. ITT was induced by i.v. administrations of 0.1 IU/kg body weight insulin (Actrapid HM) in a bolus. Insulin administration led to a comparable hypoglycemia in preflight, actual flight conditions, and before and after bed rest. ITT led to a pronounced increase in EPI levels and moderate increase in NE in preflight studies. However, an evidently reduced plasma elevation of EPI was found after insulin administration during SF and during BR. Thus, during the real microgravity in SF and simulated microgravity in BR, ITT activates the adrenomedullary system to less extent that at conditions of the Earth's gravitation. Post-flight changes in EPI and NE did not differ from those of preflight values, since SF was relatively short (8 days) and the readaptation to Earth's gravitation was fast. It seems that an increased blood flow in brain might be responsible for the reduced EPI response to insulin. Responses to ITT in physically fit subjects indicate the stimulus specificity of the deconditioning effect of 5 days of bed rest on the stress response.

Gonadal and adrenal steroid hormones in plasma and synovial fluid of patients with rheumatoid arthritis.

OBJECTIVES: Gonadal and adrenal steroids were shown to affect multiple immune processes including inflammatory response. These effects were documented, specifically, through an influence on local productions of cytokines and the functions of synovial cells at the site of inflammatory processes. The aim of this study was to investigate the levels of selected hormones in synovial fluid of knee joints of patients with rheumatoid arthritis (RA) and with osteoarthrosis (OS, control group). METHODS: The concentrations of cortisol (CORT), 17-beta-estradiol (ES), dehydroepiandrosterone (DHEA), testosterone (TE), progesterone (PRG), and aldosterone (ALD) were determined in plasma and synovial fluid. RESULTS: Significant positive correlations between the levels in plasma and synovial fluids were observed in hormones ES, PRG, TE, DHEA and ALD. In most hormones, the levels in synovial fluids were similar as in plasma; however, the content of ALD was higher in synovial fluid as compared to plasma. Higher levels of ES (in females), DHEA (in males), and ALD were observed in plasma and synovial fluids of RA patients as compared to OS patients. After adjustment to age, no significant RA vs. OS difference was noted in ES, TE, DHEA, PRG, and CORT in plasma and synovial fluid. Age-adjusted ALD concentration tended to be higher in synovial fluid of RA patients as compared to OS patients. The ratio of ES/TE concentrations in synovial fluid was significantly higher in male RA patients compared to OS group. Also the ES/CS and ES/DHEA ratios in synovial fluid were elevated in RA patients in comparison to controls. CONCLUSIONS: These results demonstrated the prevalence of pro-inflammatory hormones in synovial fluid of RA patients, suggesting the possible role of these steroid hormones in inflammatory processes.

Ethanol consumption affects stress response and insulin binding in tissues of rats.

OBJECTIVE: The mechanisms of harmful effect of excessive chronic ethanol intake on cardiovascular and neuronal systems, metabolic processes and protective effects of low ethanol intake on cerebrovascular and cardiovascular disturbances are not yet known. The aim of present study was to investigate the effect of short-term and long-term ethanol consumption on food intake, plasma levels of corticosterone (CS), glucose (G) and insulin (INS) in intact rats and in animals exposed to immobilization stress (IMO) or restrain stress (RESTR). The insulin binding to specific membrane receptors in adipocytes, muscle and liver was also determined. METHODS: Adult male rats were fed liquid diet without and with ethanol (5% per weight) for 9-12 days (short-term intake) and at the end the animals were exposed to acute IMO stress. The second group of rats was fed solid diet and without or with ethanol in drinking water (6% per volume) for 52 days (long-term ethanol intake). A part of these animals was exposed to repeated restrain stress during 42 days. The groups of pair fed rats with the same food intake as in ethanol diet fed animals were in both experiments. The food intake, plasma glucose, insulin and corticoster-one levelswere determined. Plasma cell membranes were isolated from adipose, liver and skeletal muscle tissues and insulin binding to specific receptors was determined. RESULTS: Decreased food consumption was observed after ethanol intake. Increased plasma G and CS were noted in rats fed ethanol diet for a short time. Plasma insulin levels were not affected by ethanol intake. Exposure to IMO stress resulted in increase of plasma G levels in controls and pair fed groups. A higher increase of CS plasma levels after IMO stress was noted in rats with ethanol intake for a short-time, however, no changes of plasma CS were noted after repeated exposure to restrain stress. Plasma levels of insulin were decreased after IMO and restrain stresses, while in rats fed ethanol diet for a short-time insulin decrease was deeper as compared to controls. The binding capacity of insulin receptors in adipose tissue was elevated in rats fed ethanol diet and deep decrease of insulin binding was noted in rats exposed to stress. In liver insulin binding was elevated after short-term ethanol intake and stress exposure resulted in decrease of insulin binding in ethanol fed rats. The binding capacity of insulin receptors in skeletal muscle was not changed in rats fed ethanol diet. CONCLUSIONS: The results showed 1. differences in short term and long term ethanol intake on basal glucose, insulin and corticosterone levels, 2. effects of ethanol intake on changes of insulin plasma levels and insulin binding in adipose and liver tissues after exposure to stress, 3. effects of short term ethanol intake on the response of plasma hormones to immobilization stress.

Remote controlled equipment for multiple blood withdrawal in gravitational physiology experiments.

Electro-mechanical equipment for multiple blood withdrawal from small experimental animals applied to a centrifuge with maximal 6g gravitational overloading has been developed and tested. The equipment consists of a transmitter and receiver equipped by microcomputers. Active rotor stepping motors are driving four pairs of syringes. It is also possible to measure the instantaneous gravitational force using an accelerometric transducer. This telemetrically regulated blood sampling allows studying selective effects of hypergravity during centrifugation. It can be also used for study of microgravity effects in the animal organism during space flights for the understanding of the mechanism of the changes of the activity of neuroendocrine system and metabolic processes.