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Biomedical subjects

Y Shibutani

Publications and source records attributed to Y Shibutani.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of dienogest on bleeding time, coagulation, fibrinolysis, and platelet aggregation in female rats.

We investigated the effect of dienogest on bleeding time, coagulation, fibrinolysis, and platelet aggregation in female rats compared with that of medroxyprogesterone acetate (MPA) and danazol, in order to elucidate the reason for relatively high incidence of bleeding in dienogest-treated patients with endometriosis. Dienogest caused no change in the bleeding time at a single dose of 100 mg/kg or at a repeated dose of 10 mg/kg per day for 2 weeks. The drug increased the fibrinogen level, coagulation factor II and V activities, and antithrombin III activity, but had no effect on fibrinolysis or on platelet aggregation at repeated doses of 1 and 10 mg/kg per day for 4 weeks. MPA significantly shortened the bleeding time at the same doses as dienogest. MPA increased the fibrinogen level and plasminogen activity, potentiated the platelet aggregation, and increased the platelet cholesterol-to-phospholipid ratio at a repeated dose of 10 mg/kg per day for 4 weeks. Danazol significantly shortened the bleeding time like MPA. Danazol increased the fibrinogen level, coagulation factor II, V, VII, VIII, IX, X, XI, and XII activities, and antithrombin III activity, but had no influence on the platelet aggregation at repeated doses of 10 and 100 mg/kg per day for 4 weeks. In comparison with MPA and danazol, dienogest may induce a relatively high incidence of bleeding in patients with endometriosis partially because of its minimal effect on hemostasis.

Animals↗
PubMed1999

Histopathological and biochemical studies on pancreatic fibrosis in WBN/Kob rats.

We investigated the time-course of changes in pancreatic fibrosis accompanied with pancreatitis in WBN/Kob rats. The areas of fibrosis and fatty replacement were analysed morphometrically, and biochemical measurements of pancreatic and plasma prolyl hydroxylase and of pancreatic collagenase were assessed. Male rats showed acute pancreatitis at 2-3 months of age, lesions that later underwent a transition to widespread fibrosis. The fibrosis then decreased, and the fibrotic tissue was replaced with adipose tissue. Morphometrically, the fibrotic area reached its maximal size when the rats were 4 months old, diminishing thereafter. The fibrosis occurred mainly in the intralobular space, and was principally attributable to type-III collagen. Type-I collagen scarcely appeared throughout the experimental period. Alpha-Smooth muscle actin appeared in and around myofibroblasts that developed in an early stage and diminished later in accordance with the progressive manner of fibrosis. The plasma prolyl hydroxylase level was higher in males than in females from 4 through 10 months of age. Pancreatic collagenase activity in the males also increased during the same period. These findings suggest that pancreatic fibrosis in male WBN/Kob rats is affected by the balance between prolyl hydroxylase and collagenase.

Actins↗
PubMed1999

A case of classical xanthinuria (type 1) with diabetes mellitus and Hashimoto's thyroiditis.

In a 62-year-old woman with non-insulin-dependent diabetes mellitus and Hashimoto's thyroiditis, hypouricemia was detected by a routine examination. Her plasma uric acid level was markedly low and urinary excretion of uric acid was undetectable. The high plasma and urine levels of xanthine were observed, although those of hypoxanthine were within normal ranges at rest after an overnight fast. After taking diet, plasma concentration and urinary excretion of hypoxanthine were markedly increased together with those of xanthine. The xanthine oxidase activity of duodenal mucosa was below the limits of detection. Allopurinol was metabolized to oxypurinol and pyrazinamide to 5-hydroxypyrazinamide in spite of no activity of xanthine oxidase, suggesting that aldehyde oxidase converted allopurinol to oxypurinol and pyrazinamide to 5-hydroxypyrazinamide. Based on these findings, she was diagnosed as having a subtype of classical xanthinuria type 1 with the normal plasma concentration of hypoxanthine in fast.

Diabetes Mellitus, Type 2↗
PubMed1999

Effect of highly purified eicosapentaenoic acid ethyl ester on insulin resistance and hypertension in Dahl salt-sensitive rats.

We investigated the effect of long-term administration of highly purified eicosapentaenoic acid ethyl ester (EPA-E), an n-3 polyunsaturated fatty acid derived from fish oil, in comparison to lard on the development of hypertension and insulin resistance in Dahl salt-sensitive (Dahl-S) rats fed a high-sucrose diet (HSD), a model of salt-sensitive hypertension. After 16 weeks of treatment, the glucose infusion rate (GIR) during the euglycemic insulin-glucose clamp test significantly increased in the HSD-EPA-E group compared with the HSD-water or -lard control group. The GIR was approximately three times higher in the HSD-EPA-E group versus the HSD-water or -lard control group, and it was about 70% of the rate in the calorically deprived control group fed a low-fat-high-fiber diet (LF-HFD). In addition, EPA-E significantly suppressed the elevation of plasma glucose and insulin levels after oral glucose loading. These results indicate that EPA-E prevents the development of insulin resistance in Dahl-S rats fed a HSD. Fatty acid analysis of phospholipids in skeletal muscle showed a significant increase in C18:2, C20:5, and C22:5 components in the HSD-EPA-E group and, conversely, a significant decrease in C16:0, C20:4, and C22:6. The present results indicate that the beneficial effect of EPA-E on insulin resistance in Dahl-S rats fed a HSD is likely dependent on the modification of phospholipid components in the skeletal muscle membrane. These findings suggest that EPA-E might prevent the development of insulin resistance in dietary obesity. In addition, the HSD-EPA-E group showed a significant increase in the level of uncoupling protein (UCP) in brown adipose tissue as compared with the HSD-water or -lard control group. However, EPA-E had no effect on the development of hypertension and obesity in Dahl-S rats fed the HSD.

Animals↗
PubMed1999

Protection against preterm delivery in mice by urinary trypsin inhibitor.

OBJECTIVE: To investigate the precise mechanism by which urinary trypsin inhibitor suppresses cytokine production in the prevention of preterm delivery. METHODS: In vivo and in vitro studies were performed using ascites and peritoneal macrophages obtained on day 15 of pregnancy from female C3H/HeN mice that had been impregnated by B6D2F1 male mice. Lipopolysaccharide receptor, the intracellular signal transduction system, and nuclear factor-kappaB level were examined. RESULTS: In the in vivo study, we found that urinary trypsin inhibitor ameliorated the deterioration of intraperitoneal conditions induced by lipopolysaccharide (ie, increases in ascitic volume, peritoneal cell count, and tumor necrosis factor-alpha level) and caused a decrease in the binding of lipopolysaccharide to mouse macrophages. In the in vitro studies, urinary trypsin inhibitor decreased the binding capacity of lipopolysaccharide for its receptor, blocked the intracellular signal transduction induced by lipopolysaccharide, and decreased the nuclear factor-kappaB level. Increases were induced in the binding capacity of the macrophages for urinary trypsin inhibitor and its incorporation into them in the presence of lipopolysaccharide. CONCLUSION: We postulate that urinary trypsin inhibitor may suppress the production of inflammatory cytokines induced by lipopolysaccharide in mouse peritoneal macrophages through suppression of the lipopolysaccharide receptor, inhibition of the intracellular signal transduction system, and decrease in the nuclear factor-kappaB level.

Animals↗
PubMed1999

Silver and thallium(I) complexation with dibenzo-16-crown-4.

Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivity over sodium, potassium, and rubidium ion evaluated from the solvent extraction of metal picrates, while its cation-binding ability is lower than those of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium(I) ion selectivity for 1 obtained from extraction experiments, PVC membrane thallium(I)-selective electrodes based on 1 are prepared. The electrode shows the best potentiometric selectivity coefficients for thallium(I) over potassium and rubidium than those of 2 and 3, and commercially available bis(crown ether)s (4).

Crown Ethers↗
PubMed1998

Effects of dienogest (a synthetic steroid) on coagulation, fibrinolysis, and platelet aggregation in female monkeys.

We investigated the effects of dienogest (0.1-10 mg/kg per day, p.o.) on coagulation, fibrinolysis and platelet aggregation in female rhesus monkeys. Then, we also examined those of medroxyprogesterone acetate (MPA, 10 mg/kg per day, p.o.) or danazol (10-1000 mg/kg per day, p.o.) on these parameters in the same species. In addition, we assessed the effects of dienogest (1 and 3 mg/kg per day, p.o.) or MPA (10 mg/kg per day, p.o.) on platelet aggregation and platelet lipids in female cynomolgus monkeys. At doses of 0.3 mg/kg or greater, dienogest increased the levels of several coagulation and anticoagulation factors, but had no effect on the prothrombin time, activated partial thromboplastin time, fibrinolysis, or platelet aggregation. MPA (10 mg/kg) had no effect on coagulation or fibrinolysis, but significantly potentiated platelet aggregation in response to ADP and collagen and also increased the platelet cholesterol-to-phospholipid ratio. Danazol (10 mg/kg or more) increased the activities of coagulation factors V, VII, VIII, X, XI, and XII in comparison to dienogest and MPA. Consequently, dienogest caused less potentiation of platelet aggregation than MPA and less potentiation of coagulation than danazol.

Animals↗
PubMed1998

Lipoteichoic acid induces preterm delivery in mice.

The purpose of this study was to determine whether or not lipoteichoic acid (LTA) could induce preterm delivery in mice. On days 15 and 17 of pregnancy, female C3H/HeN mice impregnated by male B6D2F1 mice were given intraperitoneal injections of LTA (12.5-75 mg/kg, single dose or repeated doses at a 3-h interval). We examined the changes in cervix, placental trophoblasts, and plasma and amniotic fluid concentrations of interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) after dosing with LTA. In addition, the effect of LTA on the contraction of isolated uterine muscle from pregnant mice was also measured. The incidence of preterm delivery was highest (100%), when the pregnant animals were treated with 75 mg/kg LTA twice on day 15 of pregnancy or with 25 mg/kg LTA twice on day 17 of pregnancy. LTA-accelerated cervical ripening and placental abruption preceding the onset of preterm delivery, as well as increased plasma and amniotic fluid concentrations of IL-1alpha, IL-6, and TNF-alpha. Also, LTA increased contraction of uterine muscle strips. In conclusion, LTA induced preterm delivery in mice in the same manner as lipopolysaccharide (LPS), but the effective dose of LTA was larger than that of LPS.

Amniotic Fluid↗
PubMed1998

Tocolytic effect of magnesium sulfate and/or urinary trypsin inhibitor against lipopolysaccharide-induced preterm delivery in mice.

BACKGROUND: The purpose of this investigation was to evaluate the effect of magnesium sulfate (magnesium) alone or along with urinary trypsin inhibitor (UTI) in a mouse model in the prevention of preterm delivery. METHODS: On day 17 of pregnancy, female C3H/HeN mice impregnated by male B6D2F1 mice were given two intraperitoneal injections of lipopolysaccharide (LPS; 50 microg/kg) at a 3-hour interval, which treatment induced a 100% incidence of preterm delivery within 25 hours of the second dose. Magnesium (4, 5, 6, 7, or 8 mg/hr, s.c.), UTI (25 x 10(4) units/kg, i.p.), magnesium (5 mg/hr, s.c.) plus UTI (25 x 10(4) units/kg, i.p.), saline solution (0.3 ml/hr, s.c.), or saline solution (0.1 ml/hr, s.c. and 2.5 ml/kg, i.p.) was administered to pregnant animals on day 18 of gestation. UTI was intraperitoneally given 5 times at 2-hour intervals from 8:00 am to 4:00 pm, and magnesium was infused subcutaneously and constantly from 8:00 am to 6:00 pm. In addition, the preventive effect of magnesium on LPS-induced contraction of uterine muscle strips and that of magnesium, UTI, or magnesium plus UTI on LPS-induced calcium influx in uterine smooth muscle cells were examined using muscle tissue isolated from pregnant mice on day 17 of gestation. RESULTS: The incidence of preterm delivery decreased significantly in a dose-dependent fashion with magnesium treatment, and there was a significant and synergistic decrease after combined treatment with magnesium plus UTI. The in vitro uterine contraction and calcium influx induced by LPS were significantly suppressed by magnesium. The latter was significantly suppressed by UTI and additively reduced by magnesium plus UTI. CONCLUSIONS: Combination therapy with magnesium plus UTI may possibly be helpful for preventing preterm delivery in humans without the severe side effects induced by hypermagnesemia.

Animals↗
PubMed1998

Effects of dienogest, a synthetic steroid, on experimental endometriosis in rats.

OBJECTIVE: Dienogest, a synthetic steroid with progestational activity, is used as a component of oral contraceptives and is currently being evaluated clinically for the treatment of endometriosis. The present study was conducted to confirm the effects of dienogest on experimental endometriosis in rats and to elucidate its mechanism of action. DESIGN: Experimental endometriosis induced by autotransplantation of endometrium in rats. METHODS: Endometrial implants, immune system, and bone mineral were investigated after 3 weeks of medication. RESULTS: Dienogest (0.1-1 mg/kg per day, p.o.) reduced the endometrial implant volume to the same extent as danazol (100 mg/kg per day, p.o.). Simultaneously, dienogest ameliorated the endometrial implant-induced alterations of the immune system: i.e. it increased the natural killer activity of peritoneal fluid cells and splenic cells, decreased the number of peritoneal fluid cells, and decreased interleukin-1beta production by peritoneal macrophages. In contrast, danazol (100 mg/kg per day, p.o.) and buserelin (30 microg/kg per day, s.c.) had none of these immunologic effects. Additionally, combined administration of dienogest (0.1 mg/kg per day) plus buserelin (0.3 microg/kg per day) suppressed the bone mineral loss induced by buserelin alone, with no reduction of the effect on endometrial implants. In vitro studies on dienogest revealed an antiproliferative effect on rat endometrial cells due to inhibition of protein kinase C activity plus a partial progestational effect. CONCLUSIONS: Dienogest appears to be a potent agent with mechanisms of action different from those of danazol and GnRH agonists currently available for the treatment of endometriosis.

Animals↗
PubMed1997

Dienogest, a novel synthetic steroid, overcomes hormone-dependent cancer in a different manner than progestins.

BACKGROUND: Dienogest is a synthetic progestational steroid that is used for contraception. It is being studied for the treatment of endometriosis, but its anticancer activity remains unknown. The authors investigated the anticancer effect of dienogest on hormone-dependent cancers. METHODS: The authors used two cell lines derived from human endometrial carcinoma (HEC-88nu cells expressing estrogen receptors [ER] but not progesterone receptors [PR] and Ishikawa cells expressing both ER and PR) and a cell line derived from human breast carcinoma (MCF-7 cells expressing both ER and PR). The authors examined the in vivo antitumor activity and the antiuterotropic activity of dienogest in mice and compared it with the activity of several progestins. RESULTS: At oral doses of 0.01-1 mg/kg/day, dienogest significantly suppressed the 17 beta-estradiol benzoate (E2)-dependent tumor growth of HEC-88nu cells, which were unresponsive to known progestins such as medroxyprogesterone acetate (MPA, 100 mg/kg/day, administered orally) and norethisterone (NES, 100 mg/kg/ day, administered orally). The suppressive effect of dienogest on tumor growth was not diminished in the presence of excess MPA. Dienogest also suppressed the E2-dependent tumor growth of both Ishikawa and MCF-7 cells, both of which responded to MPA. However, the minimum effective dose of dienogest (0.01-1 mg/kg/day) was much lower than that of MPA (100 mg/kg/day). In contrast, dienogest did not suppress the E2-induced increase in uterine weight, whereas MPA and NES suppressed it significantly. CONCLUSIONS: Dienogest showed potent anticancer activity against hormone-dependent cancers at doses at which progestins show no activity.

Animals↗
PubMed1997

Influence of highly purified eicosapentaenoic acid ethyl ester on insulin resistance in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous non-insulin-dependent diabetes mellitus.

We investigated the effect of long-term administration of highly purified eicosapentaenoic acid ethyl ester (EPA-E), an n-3 polyunsaturated fatty acid derived from fish oil, in comparison to the effects of lard, olive oil, safflower oil, or distilled water as the control on the development of insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of spontaneous non-insulin-dependent diabetes mellitus (NIDDM) with obesity. After 17 or 18 weeks of treatment, the glucose infusion rate (GIR) in the euglycemic insulin-glucose clamp test only showed a significant increase in EPA-E-treated rats compared with control rats given distilled water alone as the vehicle. The GIR in EPA-E-treated animals was approximately three times greater than in the controls. This is the first report to display the influence of various fatty acids on the development of insulin resistance in OLETF rats. We demonstrated that EPA-E prevents the onset of insulin resistance, whereas olive oil and safflower oil have no effect and lard exacerbates insulin resistance. Fatty acid analysis of phospholipids in skeletal muscle showed a significant increase of the C18:2, C20:5, and C22:5 components in EPA-E-treated rats and, conversely, a significant decrease in C20:4. In addition, EPA-E-treated rats showed a significant increase in GLUT4 mRNA in skeletal muscle when compared with control rats. Our results indicate that the beneficial effect of EPA-E on insulin resistance in OLETF rats is likely to be dependent on modification of the phospholipid components of the skeletal muscle membrane. These findings suggest that dietary fatty acids may play a key role in the development of insulin resistance in patients with NIDDM.

Animals↗
PubMed1997

Trophoblastic apoptosis in mice with preterm delivery and its suppression by urinary trypsin inhibitor.

OBJECTIVE: To investigate histopathologic changes of the placenta in mice with preterm delivery induced by lipopolysaccharide and the effect of urinary trypsin inhibitor. METHODS: Female C3H/HeN mice impregnated by male B6D2F1 mice were treated with lipopolysaccharide (50 micrograms/kg, intraperitoneally) or lipopolysaccharide plus urinary trypsin inhibitor (25 x 10(4) U/kg, intraperitoneally). At 3, 6, 9, and 18 hours after the second dose of lipopolysaccharide, and at delivery in the control and urinary trypsin inhibitor-treated groups, the concentrations, of interleukin-1 alpha and tumor necrosis factor-alpha were determined in serum and amniotic fluid. Subsequently, the placentas were examined. In the same manner, we examined mice treated with interleukin-1 alpha (250 micrograms/kg, subcutaneously) on day 15 of pregnancy and intact mice on days 15 and 18 of pregnancy as well as at delivery. To assess the direct action of cytokines, we cultured placental slices with tumor necrosis factor-alpha, interleukin-1 alpha, or tumor necrosis factor-alpha plus urinary trypsin inhibitor and examined them morphologically. RESULTS: Control mice were characterized by trophoblastic apoptosis and increased serum levels of tumor necrosis factor-alpha and interleukin-1 alpha. In contrast, urinary trypsin inhibitor-treated mice showed suppression of apoptosis and lower cytokine levels. Interleukin-1 alpha induced trophoblastic apoptosis and increased the serum level of tumor necrosis factor-alpha. The in vitro study showed that tumor necrosis factor-alpha directly induced trophoblastic apoptosis in placental slices. CONCLUSION: We demonstrated that trophoblastic apoptosis occurs in the placentas of a mouse model with preterm delivery induced by lipopolysaccharide. We postulated that apoptosis may lead to placental abruption, and its development may be prevented by treatment with urinary trypsin inhibitor.

Animals↗
PubMed1997

QT corrected for heart rate and relation between QT and RR intervals in beagle dogs.

The beagle dog has been widely used in cardiovascular research, but the adequacy of QT prediction formulas in dogs over a wide range of RR intervals has not been evaluated sufficiently. We investigated the QT-RR relation in beagles by analysis of the QT and preceding RR intervals obtained from 24-h ambulatory electrocardiograms. The acceptability of 14 QT prediction formulas was evaluated by use of 100-150 selected pairs of QT-RR points per animal in seven male and seven female beagles. The accuracy of fit with the measured data was assessed according to the minimum Akaike information criterion. The best fit was given by the logarithmic and inverse Kovács' formulas among one- and two-parameter linear regression equations, respectively. Exponential formulas produced a better fit than did the linear regression formulas, but are impractical because of the complicated interpretation of parameters due to the nonlinearity. In addition, the results obtained under physiological conditions were also confirmed by those of the pharmacological intervention study with disopyramide. Consequently, we propose a one-parameter logarithmic formula (QTc= log600 x QT/logRR) for correcting the QT interval for a heart rate of 100 bpm and the inverse Kovács' formula for evaluating a reverse-use-dependency of QT prolongation.

Animals↗
PubMed1997

Preventive effect of ritodrine hydrochloride and/or urinary trypsin inhibitor against lipopolysaccharide-induced preterm delivery in mice.

BACKGROUND: The purpose of this study was to confirm the preventive effect of ritodrine hydrochloride (ritodrine) alone or ritodrine plus urinary trypsin inhibitor (UTI) in a mouse model of preterm delivery. METHODS: On day 17 of pregnancy, female C3H/HeN mice impregnated by male B6D2F1 mice were given two intraperitoneal injections of lipopolysaccharide (LPS) (50 micrograms/kg) at a 3-hour interval, which induced a 100% incidence of preterm delivery within 25 hours of the second dose. Ritodrine (1, 3, or 10 mg/kg, p.o.), UTI (25 X 10(4) units/kg, i.p.), ritodrine (3 mg/kg, p.o.) plus UTI (25 x 10(4) units/kg, i.p.), distilled water (10 ml/kg, p.o.), or distilled water (10 mg/kg, p.o.) plus saline solution (10 ml/kg, i.p.) were administered to the pregnant animals 10 times at 1-hour intervals from 8:00 AM to 5:00 PM on day 18 of pregnancy. In addition, the preventive effect of ritodrine, UTI, or ritodrine plus UTI was examined on LPS-induced contraction of uterine muscle strips isolated from pregnant mice on day 17 of gestation. RESULTS: The incidence of preterm delivery decreased significantly in a dose-dependent fashion with ritodrine treatment, and there was a significant and synergistic decrease after combined treatment with ritodrine plus UTI. The in vitro uterine contraction induced by LPS was significantly suppressed by both ritodrine and UTI. CONCLUSIONS: Combination therapy with ritodrine plus UTI may be helpful for preventing preterm delivery in humans without the cardiovascular side effects that often accompany treatment with ritodrine alone.

Adrenergic beta-Agonists↗
PubMed1997

Ability of intrauterine bacterial lipopolysaccharide to cause in situ uterine contractions in pregnant rabbits.

BACKGROUND: To investigate the ability of bacterial lipopolysaccharide delivered by the intra-uterine route to cause uterine contractions in rabbits, and to assess the suppressive effect of urinary trypsin inhibitor on them. METHODS: Both pregnant and non-pregnant rabbits were chronically implanted with a force-transducer to make it possible to record isometric uterine contractions under unanesthetized and unrestrained conditions. Lipopolysaccharide (10 micrograms/animal) was administered via a catheter to their uteri; and then, after confirmation of lipopolysaccharide-induced uterine contractions, urinary trypsin inhibitor (3,000 or 10,000 units/animal/time) or saline solution was injected through the catheter, 5 times for pregnant animals or 3 times for non-pregnant animals at 1-hour intervals in both cases. Their uterine contractions were continuously recorded for 3 to 5 hours. Effects of lipopolysaccharide (10 micrograms/ml) and urinary trypsin inhibitor (100 and 1,000 units/ml) on the contraction of isolated uteri from pregnant mice were also measured, as was their production of prostaglandin E2 and prostaglandin F2 alpha by an enzyme immunoassay method. RESULTS: Lipopolysaccharide augmented the in situ uterine contractions in both pregnant and non-pregnant rabbits, as well as the in vitro contractions of isolated uteri from pregnant mice. Lipopolysaccharide also increased the uterine prostaglandin production. Urinary trypsin inhibitor inhibited significantly the lipopolysaccharide-induced uterine contractions and the prostaglandin production. CONCLUSIONS: Lipopolysaccharide enhanced uterine contractions through, at least partly, a direct mechanism via uterine prostaglandin production, which action could explain the onset of preterm delivery due to intrauterine bacterial infection. As urinary trypsin inhibitor suppressed the lipopolysaccharide-induced uterine contractions, this inhibitor may be a hopeful candidate of a drug for prevention of preterm delivery.

Animals↗
PubMed1997

Animal studies on the endocrinological profile of dienogest, a novel synthetic steroid.

Dienogest is an orally active synthetic steroid that is used for contraception and is currently being studied for the possible treatment of endometriosis. Earlier we demonstrated that dienogest had therapeutic effects on experimental endometriosis in rats and that its mechanisms of action were different from those of drugs currently on the market for the treatment of endometriosis. We also reported preclinically that dienogest showed a potential anticancer action against hormone-dependent cancers that was different from that of progestins. Accordingly, we obtained preclinical background data for the above-described clinical applications and extension of the clinical use of the drug in the near future by investigating the endocrinological profile of dienogest in rabbits and rats. Dienogest was characterized by having a moderate binding affinity for progesterone receptors and by progestational activities: it stimulated endometrial proliferation (> or = 0.01 mg/kg) that was only partially inhibited by RU-486, and induced carbonic anhydrase activity in endometrium (> or = 0.01 mg/kg). Also, it was slightly uterotrophic (> or = 1 mg/kg) with very low binding affinity for oestrogen receptors but without biological androgenic and anabolic activities (100 mg/kg), with neither glucocorticoid activity nor mineralocorticoid activity (100 mg/kg), and with very slight binding affinity for human sex hormone-binding globulin. These findings suggest that dienogest is not a pure progestin and appears to induce fewer side effects than drugs currently on the market for the treatment of endometriosis.

Animals↗