[Hemophagocytic lymphohistiocytosis caused by hematogenous disseminated pulmonary tuberculosis: A case report].

Hemophagocytic lymphohistiocytosis (HLH) was a life-threatening syndrome due to the uncontrolled immune activation of cytotoxic T lymphocytes, natural killer (NK) cells, and macrophages. HLH is characterized by primary and secondary causes, the early diagnosis and treatment of patients are closely related to the prognosis and clinical outcome of patients. The clinical presentation is variable but mostly includes prolonged fever, splenomegaly, coagulopathy, hypertriglyceridemia, and hemophagocytosis, none of them is specific and particular for HLH. Tuberculosis (TB) infection is one of the causes of HLH. HLH caused by TB is very rare clinically, but it has a high mortality. For patients with fever of unknown origin, HLH-related clinical manifestations sometimes present before the final diagnosis of TB, and HLH is associated with the most significant mortality rate. This article is mainly about a 28-year-old patient with HLH who suffered from severe TB infection. The patient attended a hospital with a history of 2 months of prolonged fever, 10 days booger and subcutaneous hemorrhage in lower limbs. Before this, he was in good health and denied any history of tuberculosis exposure. Combined with relevant laboratory test results (such as splenomegaly, hemoglobin, platelet count, and hypertriglyceridemia) and clinical manifestations (e.g. fever), the patient was diagnosed with hemophagocytic lymphohistiocytosis, but the etiology of HLH remained to be determined. To confirm the etiology, the patient was asked about the relevant medical history (intermittent low back pain) and was performed chest CT scan, bone marrow biopsy, and fundus photography. Finally, he was diagnosed with hemophagocytic lymphohistiocytosis caused by hematogenous disseminated pulmonary tuberculosis. In response to this, intravenous methylprednisolone and anti-tuberculosis treatment (isoniazid, pyrazinamide, moxifloxacin, and amikacin) were administered to the patient. After more than a month of treatment, the patient recovered from HLH caused by severe TB infection. Therefore, this case suggests that we should be vigilant to the patient who admitted to the hospital with fever for unknown reasons, to diagnose HLH as early as possible and clarify its cause, then perform interventions and treatment, especially HLH secondary to tuberculosis. Also, cases of atypical TB and severe TB should be carefully monitored to achieve early diagnosis and early intervention.

Is 2-methoxyestradiol an endogenous estrogen metabolite that inhibits mammary carcinogenesis?

Catechol estrogens (2- or 4-hydroxyestradiol and 2- or 4-hydroxyestrone) are chemically reactive estrogen metabolites that are O-methylated to less polar monomethyl ethers by catechol-O-methyltransferase, an enzyme present in many tissues such as the liver, kidney, brain, placenta, uterus, and mammary gland. In the present report, we review recent studies on the antitumorigenic and antiangiogenic effects of exogenously administered 2-methoxyestradiol in vitro and in vivo. We also discuss data that suggest that endogenous formation of 2-methoxyestradiol (and its 2-hydroxyestradiol precursor) may have a protective effect on estrogen-induced cancers in target organs. Although the molecular mechanism of action of 2-methoxyestradiol is not clear, we suggest that some unique effects of 2-methoxyestradiol may be mediated by a specific intracellular effector or receptor that is refractory to the parent hormone, estradiol. Additional research is needed to identify factors that regulate the metabolic formation and disposition of 2-methoxyestradiol in liver and in target cells and to evaluate the effects of modulating 2-methoxyestradiol formation on estrogen-induced carcinogenesis.

Effect of dietary 2(3)-tert-butyl-4-hydroxyanisole on the metabolism and action of estradiol and estrone in female CD-1 mice.

Administration of 0.75% 2(3)-tert-butyl-4-hydroxyanisole (BHA) in AIN-76A diet to female CD-1 mice for 3 weeks increased liver microsomal glucuronidation of estradiol, estrone, 4-aminophenol, and 4-nitrophenol by 103, 187, 162, and 92%, respectively (at pH 7.4). The overall rate of NADPH-dependent metabolism of estradiol and estrone by liver microsomes of BHA-treated animals as determined by substrate disappearance was increased by 20-40% over that by liver microsomes from control animals. The rate of 2-hydroxylation of estradiol and estrone (the major metabolic pathway) was increased by 24-38%, the rate of formation of 6alpha-hydroxyestradiol plus 6beta-hydroxyestradiol was increased by 90-115%, and the rate of 6beta-hydroxyestrone formation (a minor metabolite formed in liver microsomes from control mice) was increased by approximately 370% over controls. In contrast, BHA administration had little or no effect on the liver microsomal formation of 4- and 16alpha-hydroxylated estradiol and estrone metabolites. Measurable levels of estradiol and estrone were observed in the serum and uterus of ovariectomized CD-1 mice at 30 min after a single i.p. injection of 100 or 300 ng of estradiol or estrone, and these levels were decreased by 30-60% in animals fed a 0.75% BHA diet for 18 days prior to the injection of estrogen. Feeding a 0.75% BHA-supplemented diet to ovariectomized CD-1 mice for 18 days inhibited the uterotropic effect of estradiol or estrone (45 or 75 ng/mouse, i.p. once daily for 3 days) as compared to the response of animals fed the control diet. BHA administration also inhibited estradiol- or estrone-stimulated [3H]thymidine incorporation into uterine DNA. In conclusion, feeding a 0.75% BHA-supplemented diet to female CD-1 mice for 2-3 weeks increased the activities of liver microsomal enzymes that catalyze uridine 5'-diphosphoglucuronic acid-dependent glucuronidation and NADPH-dependent oxidation of estradiol and estrone, enhanced the in vivo metabolism of these estrogens, and inhibited their uterotropic action.

Preferential growth stimulation of mammary glands over uterine endometrium in female rats by a naturally occurring estradiol-17beta-fatty acid ester.

We hypothesize that the endogenously present lipoidal estrogen fatty acid esters may have a stronger mitogenic action in the fat-rich mammary tissues than in the uterus. To test this hypothesis, we compared the activity of estradiol-17beta-stearate (E(2)-17beta-S) with that of estradiol-17beta (E(2)) in stimulating the growth of mammary glandular cells versus the growth of uterine endometrial cells in ovariectomized female Sprague Dawley rats. Experimentally, an estimated 0.5 or 5 nmol of E(2)-17beta-S or E(2) was released daily to ovariectomized female rats through an Alzet pump implanted under the back skin of the animal for 10 or 23 days. The growth-stimulatory effect of E(2)-17beta-S and E(2) on mammary glandular cells was determined according to 5-bromo-2'-deoxyuridine labeling indices, and their effect on the uterus was determined by measuring both the 5-bromo-2'-deoxyuridine labeling index and the uterine wet weight. Our results showed that chronic treatment of ovariectomized female rats with 0.5 or 5 nmol/day E(2)-17beta-S for 10 or 23 days had a stronger stimulatory effect on mammary glandular cell proliferation than treatment with equimolar doses of E(2). In the uterus, however, E(2) was more active in stimulating the proliferation of uterine endometrial cells than E(2)-17beta-S at equimolar doses. Our results demonstrated, for the first time, that a naturally occurring estradiol-17beta-fatty acid ester has a differential, strong mitogenic effect in the fat-rich mammary tissues, and this effect was not observed with E(2). It is tempting to suggest that the fatty acid esters of the endogenous estrogens and their bioactive metabolites (e.g., 4-hydroxyestradiol and 16alpha-hydroxyestrone) may be of unique importance for stimulating cell growth and possibly also for inducing tumor formation in the fat-rich mammary tissues as compared with the uterus. More studies are warranted to test these ideas.

Human and animal spongiform encephalopathies are the result of chronic autoimmune attack in the CNS: a novel medical theory supported by overwhelming experimental evidence.

Spongiform encephalopathies, also called "prion diseases", are fatal degenerative diseases of the central nervous system which can occur in animals (such as the "mad cow disease" in cattle) and also in humans. This paper presents a novel medical theory concerning the pathogenic mechanisms for various human and animal spongiform encephalopathies. It is hypothesized that various forms of prion diseases are essentially autoimmune diseases, resulting from chronic autoimmune attack of the central nervous system. A key step in the pathogenic process leading towards the development of spongiform encephalopathies involves the production of specific autoimmune antibodies against the disease-causing prion protein (PrPsc) and possibly other immunogenic macromolecules present in the brain. As precisely explained in this paper, the autoimmune antibodies produced against PrPsc are responsible for the conversion of the normal cellular prion protein (PrPc) to PrPsc, for the accumulation of PrPsc in the brain and other peripheral tissues, and also for the initiation of an antibody-mediated chronic autoimmune attack of the central nervous system neurons, which would contribute to the development of characteristic pathological changes and clinical symptoms associated with spongiform encephalopathies. The validity and correctness of the proposed theory is supported by an overwhelming body of experimental observations that are scattered in the biomedical literature. In addition, the theory also offers practical new strategies for early diagnosis, treatment, and prevention of various human and animal prion diseases.

Effect of transforming growth factor beta on parathyroid hormone receptor binding and cAMP formation in rat osteosarcoma cells.

Transforming growth factor beta (TGF-beta) is now recognized as an important growth regulator and modulator in bone, where it apparently acts in an autocrine or paracrine fashion. In an effort to help elucidate how TGF-beta may interact with parathyroid hormone (PTH) to influence bone turnover, we examined the idea that TGF-beta might alter the number or affinity of PTH receptors in osteoblastic bone cells, PTH receptor binding was assessed in cultured ROS 17/2.8 cells using [125I]PTHrP-(1-34) as labeled ligand. Specific binding to intact cells was measured in the presence of up to 1 microM unlabeled rPTH-(1-34), and cAMP in cell extracts was determined by RIA. Incubation of ROS cells with 2 ng/ml of TGF-beta for the maximally effective time of 3 days increased the number of PTH binding sites (Bmax) by 47 +/- 13%, with no change in the KD (3 nM). TGF-beta also increased the intracellular cAMP response to 0.3 nM rPTH-(1-34) (ED50) by 53 +/- 22%. Both effects were dose dependent, with 1-4 ng/ml of TGF-beta producing maximal effects, and both effects were blocked by the protein synthesis inhibitor cycloheximide (2-5 microM). Since TGF-beta induced comparable increases in both PTH binding and cAMP formation, the findings suggest that TGF-beta can increase the number of functional PTH receptors in cultured ROS 17/2.8 cells. This effect may reflect an action of TGF-beta to slow replication and promote differentiated functions in these cells.

The carcinogenic activity of ethinyl estrogens is determined by both their hormonal characteristics and their conversion to catechol metabolites.

Estrogens induce kidney tumors in Syrian hamsters. The mechanism of carcinogenesis is unknown and has been investigated in this study using a weak carcinogen, 17 alpha-ethinyl estradiol (EE), and a strongly carcinogenic estrogen, 17 alpha-ethinyl-11 beta-methoxyestradiol [moxestrol (MOX)]. We investigated rates of conversion of estrogens to catechol metabolites and rates of their methylation to methyl ethers in order to examine the hypothesis that catechol metabolites mediate estrogen-induced carcinogenesis. Rates of conversion of MOX to catechol metabolites by hamster liver or kidney cortex microsomes were 40-50% of those with estradiol as substrate. However, the rate of catechol-O-methyltransferase-catalyzed methylation of 2-hydroxy-MOX was the least of the catechol metabolites examined when incubated with cytosol of hamster kidney. In contrast, EE was converted to catechol metabolites by hamster liver and kidney microsomes at rates 25-35% of those obtained with estradiol. These catechol metabolites of EE were methylated by catechol-O-methyltransferase of hamster kidney cytosol at rates slightly lower than those observed with catechols of estradiol. The progesterone receptor binding of EE and MOX was investigated, because progesterone is known to inhibit estrogen-induced carcinogenesis in the hamster kidney. Neither estradiol nor MOX inhibited the binding of progesterone to its receptor in hamster kidney cytosol. However, in the presence of 20 nM EE, the binding affinity of radiolabeled progesterone to receptor was inhibited (increase in Kd from 0.98 nM in controls to 3.02 nM in the presence of EE). Maximum binding values (5.0 fmol/mg protein in controls and 6.0 fmol/mg protein in the presence of EE) were not significantly altered. These results support the hypothesis that estrogen-induced carcinogenesis is mediated by catechol estrogen metabolites. The carcinogenic estrogen MOX is converted to catechol metabolites at lower rates than estradiol, but their methylation may be sterically hindered by the 11 beta-methoxy substituent. In contrast, the rates of conversion of the weakly carcinogenic EE to catechol metabolites are low, whereas their methylation rates are only marginally lower than those of 2- and 4-hydroxyestradiol. The decreased capacity of EE to form catechol metabolites in conjunction with its partial progestin agonist activity in the target organ of hamsters may contribute to the low tumor incidence.

Conversion of estrone to 2- and 4-hydroxyestrone by hamster kidney and liver microsomes: implications for the mechanism of estrogen-induced carcinogenesis.

As part of an ongoing investigation of the role of metabolic activation of estrogens in the genesis of cancers such as estrogen-induced renal tumors in hamsters, we have 1) determined steroid-17 beta-oxidoreductase activity of microsomes and cytosol prepared from hamster kidney and liver; 2) compared the rates of 2-, 4-, and 16 alpha-hydroxylations of estrone by microsomes from hamster kidney and liver; and 3) determined the rates of inactivation of 2- and 4-hydroxyestrone by catechol-O-methyltransferase from hamster kidney and by purified enzyme. Microsomal steroid-17 beta-oxidoreductase activity in hamster kidney and liver was low and favored the conversion of estrone to estradiol. Cytosolic steroid-17 beta-oxidoreductase activity was only barely detectable in both liver and kidney. Using hepatic microsomes, the rate of 2-hydroxylation of estrone was comparable to that found previously using estradiol as substrate, whereas 4-hydroxylation of estrone was double that of estradiol. Using renal microsomes, the rates of 2- and 4-hydroxylation of estrone were 10- to 20-fold higher than those with estradiol as substrate, and the ratio of 2- to 4-hydroxylation was about 2:1. Fadrozole hydrochloride was an equally good inhibitor of rates of 2- and 4-hydroxylation of estrone (20 microM) by hepatic microsomes (IC50, approximately 25 microM). Corresponding IC50 values with renal microsomes were less than 2 microM, and 2-hydroxylation of estrone was inhibited by Fadrozole hydrochloride up to 15% more than 4-hydroxylation. Treatment of hamsters with estradiol for 2 months decreased rates of 2- and 4-hydroxylation of estrone by renal microsomes by approximately 95%. The rate of conversion of estrone to 16 alpha-hydroxyestrone by hepatic microsomes was 10-20% that of 2-hydroxylation. Renal microsomes catalyzed 16 alpha-hydroxylation of estrone at an even lower rate (approximately 5% of that of 2-hydroxylation). Rates of O-methylation of 2- and 4-hydroxyestrone by hamster kidney cytosol were comparable to those of 2- and 4-hydroxyestradiol. In conclusion, conversion of estrone to its catechol metabolites by microsomes of hamster kidney, a target organ of estrogen-induced carcinogenesis, is quantitatively more important than the conversion to 16 alpha-hydroxyestrone. The findings are consistent with the postulated role of catechol estrogens generated in situ in estrone-induced carcinogenesis.

PPARalpha-dependent induction of liver microsomal esterification of estradiol and testosterone by a prototypical peroxisome proliferator.

Fatty acyl-coenzyme A:estradiol acyltransferase in liver microsomes catalyzes the formation of estradiol fatty acid esters. These estrogen esters are extremely lipophilic and have prolonged hormonal activity because they are slowly metabolized and slowly release estradiol. Our previous studies showed that treatment of female rats with clofibrate or gemfibrozil (peroxisome proliferators commonly used as hypolipidemic drugs) markedly stimulated the liver microsomal esterification of estradiol. Although clofibrate administration is a potent inducer of liver microsomal fatty acyl-coenzyme A:estradiol acyltransferase in rats, it is a poor inducer in mice. In contrast to these observations, Wy-14,643 (an exceptionally potent prototypical peroxisome proliferator) is a strong inducer of fatty acyl-coenzyme A:estradiol acyltransferase in mice. To explore the role of PPARalpha in the induction of fatty acyl-coenzyme A:estradiol acyltransferase and fatty acyl-coenzyme A:testosterone acyltransferase activities by peroxisome proliferators, we fed 0.1% Wy-14,643 to female wild-type and PPARalpha null mice for 11 d. The liver microsomal acyl-coenzyme A:estradiol acyltransferase and acyl-coenzyme A:testosterone acyltransferase activities were increased 4- to 5-fold in wild-type mice fed Wy-14,643, but no increase was observed in null mice. These results demonstrate that induction of acyl-coenzyme A:estradiol acyltransferase and acyl-coenzyme A:testosterone acyltransferase activities by a prototypical peroxisome proliferator is dependent on PPARalpha.

Similarities and differences in the glucuronidation of estradiol and estrone by UDP-glucuronosyltransferase in liver microsomes from male and female rats.

In this study, we evaluated the effects of pH, in vitro inhibitors, in vivo enzyme inducers, age, and sex on the glucuronidation of estradiol and estrone by rat liver microsomes. Although the pH dependence curves for the glucuronidation of estradiol and estrone were similar, the pH dependence curves for these estrogens by liver microsomes from adult male rats were very different from those by liver microsomes from adult female rats. These results suggest that liver microsomes from adult male and have different estrogen glucuronosyltransferases. Liver microsomes from immature or adult female rats catalyzed the glucuronidation of estrone and estradiol more rapidly than liver microsomes from age-matched male rats. Intraperitoneal injection of sodium phenobarbital (75 mg/kg/day) or dexamethasone (75 mg/kg/day) into immature or adult male or female rats for 3-4 days resulted in a 33-58% increase in liver microsomal glucuronosyltransferase activity for estradiol, but there was little or no stimulatory effect on glucuronosyltransferase activity for estrone. Treatment of immature or adult male or female rats with 3-methylcholanthrene (25 mg/kg/day) for 3-4 days did not stimulate liver microsomal glucuronosyltransferase activity for estradiol or estrone, but the glucuronidation of 4-nitrophenol was stimulated several-fold. The in vitro addition of testosterone had a strong inhibitory effect on the glucuronidation of estradiol and estrone by liver microsomes from both adult male and female rats, whereas the in vitro addition of 4-nitrophenol had a slightly greater inhibitory effect on the glucuronidation of estradiol and estrone by adult male liver microsomes than by adult female liver microsomes. In conclusion, our results suggest that male and female rat livers have different estrogen glucuronosyltransferases and that the glucuronidation of estradiol, estrone, and 4-nitrophenol is catalyzed by different glucuronosyltransferases that are under different regulatory control.

On the mechanism of homocysteine pathophysiology and pathogenesis: a unifying hypothesis.

Studies have shown that hyperhomocysteinemia is an important and independent risk factor for a variety of human cardiovascular diseases. In this paper, a unifying hypothesis is proposed which suggests that hyperhomocysteinemia may exert its pathogenic effects largely through metabolic accumulation of S-adenosyl-L-homocysteine, a strong noncompetitive inhibitor of the catechol-O-methyltransferase (COMT)-mediated methylation metabolism of various catechol substrates (such as catecholamines and catechol estrogens). In the case of endogenous catecholamines in peripheral tissues, inhibition of their methylation by S-adenosyl-L-homocysteine will result in elevation of blood or tissue levels of catecholamines, and consequently, over-stimulation of the cardiovascular system's functions. Moreover, because the vasculature is constantly exposed to high levels of endogenous catecholamines (due to high levels of circulating neurohormone epinephrine plus rich innervation with sympathetic nerve terminals), vascular endothelial cells would incur chronic cumulative damage caused by the large amounts of the oxidative products (catechol quinones/semiquinones and oxyradicals) generated from endogenous catecholamines. This mechanistic explanation for the vascular toxicity of hyperhomocysteinemia is supported by many experimental findings, and it also fully agrees with the known protective effects of folate, vitamins B6 and B12 in hyperhomocysteinemic patients. In addition, based on the predictable effects of hyperhomocysteinemia on the methylation of catecholamines in the central nervous system as well as on the methylation of catechol estrogens in estrogen target organs, it is also suggested that hyperhomocysteinemia is an important risk factor for the development of neurodegerative disorders (Parkinson's and Alzheimer's diseases) and estrogen-induced hormonal cancers. More studies are warranted to test these intriguing ideas.

Effects of tea polyphenols and flavonoids on liver microsomal glucuronidation of estradiol and estrone.

Administration of 0.5 or 1% lyophilized green tea (5 or 10 mg tea solids per ml, respectively) as the sole source of drinking fluid to female Long-Evans rats for 18 days stimulated liver microsomal glucuronidation of estrone, estradiol and 4-nitrophenol by 30-37%, 15-27% and 26-60%, respectively. Oral administration of 0.5% lyophilized green tea to female CD-1 mice for 18 days stimulated liver microsomal glucuronidation of estrone, estradiol and 4-nitrophenol by 33-37%, 12-22% and 172-191%, respectively. The in vitro addition of a green tea polyphenol mixture, a black tea polyphenol mixture or (-)-epigallocatechin gallate inhibited rat liver microsomal glucuronidation of estrone and estradiol in a concentration-dependent manner and their IC50 values for inhibition of estrogen metabolism were approximately 12.5, 50 and 10 microg/ml, respectively. Enzyme kinetic analysis indicates that the inhibition of estrone glucuronidation by 10 microM (-)-epigallocatechin gallate was competitive while inhibition by 50 microM (-)-epigallocatechin gallate was noncompetitive. Similarly, several flavonoids (naringenin, hesperetin, kaempferol, quercetin, rutin, flavone, alpha-naphthoflavone and beta-naphthoflavone) also inhibited rat liver microsomal glucuronidation of estrone and estradiol to varying degrees. Naringenin and hesperetin displayed the strongest inhibitory effects (IC50 value of approximately 25 microM). These two hydroxylated flavonoids had a competitive mechanism of enzyme inhibition for estrone glucuronidation at a 10 microM inhibitor concentration and a predominantly noncompetitive mechanism of inhibition at a 50 microM inhibitor concentration.

The competitive and noncompetitive antagonism of receptor-mediated drug actions in the presence of spare receptors.

According to the original receptor occupancy theory proposed by Clark in the 1930s, the percent occupancy of total available receptors by an agonist is linearly related to the response (or effect). However, the first recognition of "receptor reserve" or "spare receptors" mainly by Furchgott and Stephenson in separate studies about two decades ago has profoundly modified the original receptor occupancy theory, that is, the receptor occupancy is not directly proportional to the responses, and the ED50 (or EC50) could be much lower than the equilibrium dissociation constant (Kd). To date, the receptor reserve phenomenon has been characterized in an increasing number of receptor systems. In theory, spare receptors may influence the profile of dose-response (D-R) relationship as well as that of the competitive or noncompetitive antagonism of receptor-mediated drug actions.

An in vitro bioassay for testing the direct effect of luteinizing hormone-releasing hormone agonists on progesterone secretion by rat ovarian cells.

It is known that luteinizing hormone-releasing hormone (LHRH) and its agonistic analogs could act directly on various extrapituitary target tissues by activating their specific receptors present in these tissues. In this report, we proposed an in vitro assay method for testing the bioactivities of LHRH agonists based on their inhibitory effect on human chorionic gonadotropin (HCG)-induced progesterone secretion by rat ovarian cells. Ovaries from five to ten pseudopregnant rats (prepared by sequential hormone treatment) were mechanically and enzymatically dispersed to prepare luteal cell-rich suspensions. Addition of [D-Ala6, Pro9-Ethylamide]LHRH to ovarian cell suspensions inhibited different concentrations (1, 10 or 100 mIU/ml) of HCG-induced progesterone secretion in concentration-dependent manners. In the presence of 1 mIU/ml HCG as a stimulant, the percent inhibition of progesterone secretion by the same concentrations of [D-Ala6, Pro9-Ethylamide]LHRH was most pronounced and the results were usually more readily reproducible and with less experimental variations. In this study, LHRH and twelve agonistic analogs (at 10(-9) and 10(-7) M concentrations) were compared for their inhibitory effect on 1 mIU/ml HCG-induced progesterone secretion, and their relative agonistic activities were evaluated based on their inhibition potencies. This in vitro bioassay is simple and time- and cost-efficient, and can be employed as a supplementary method to the commonly utilized bioassays for LHRH agonists. This method may also be useful in screening for LHRH agonists with potent extrapituitary effects.

Effect of age and sex on the inducibility of hepatic microsomal 4-nitrophenol UDP-glucuronyltransferase activity in rats.

In this report, we examined the effect of age and sex of Long-Evans rats on the inducibility of 4-nitrophenol glucuronyltransferase activity in liver microsomes of animals treated with phenobarbital, dexamethasone, or 3-methylcholanthrene. Glucuronyltransferase activity in control male liver microsomes was approximately 50-75% higher than that in control female liver microsomes. Treatment with sodium phenobarbital (i.p., 75 mg/kg/day) for 3-4 days increased glucuronyltransferase activity by approximately 100% and 60% in liver microsomes from adult female and male rats, respectively, but did not influence this activity in liver microsomes from immature female and male rats. Treatment with dexamethasone (i.p., 75 mg/kg/day) for 3-4 days increased glucuronyltransferase activity by approximately 4-fold in liver microsomes from immature female rats but markedly decreased this enzyme activity in liver microsomes from adult female rats, adult male rats, and immature male rats. Treatment with 3-methylcholanthrene (i.p., 25 mg/kg/day) for 3-4 days increased glucuronyltransferase activity by approximately 10- to 13-fold in liver microsomes from immature female rats, adult female rats, and adult male rats, but only increased this enzyme activity by approximately 1-fold in liver microsomes from immature male rats. In conclusion, the extent of induction of hepatic microsomal glucuronyltransferase activity for 4-nitrophenol is affected dramatically by the age and sex of the animals.

Strong inhibition of estrone-3-sulfatase activity by pregnenolone 16alpha-carbonitrile but not by several analogs lacking a 16alpha-nitrile group.

In recent years, development of potent inhibitors for estrogen sulfatases has become an actively pursued strategy for chemoprevention and/or chemotherapy of estrogen-dependent human breast cancers. We report here our findings that pregnenolone 16alpha-carbonitrile (PCN) is a potent inhibitor of estrone-3-sulfatase activity of rats and also humans. PCN inhibited in a concentration-dependent manner the desulfation of estrone-3-sulfate catalyzed by liver microsomal and nuclear fractions of female Sprague-Dawley rats. The inhibition of estrone-3-sulfatase activity in these two subcellular fractions showed a biphasic pattern, with a highly sensitive phase seen at 78 nM to 1.25 microm of PCN followed by a markedly less-sensitive phase at > 2.5 microm of PCN. Interestingly, several of PCN's structural analogs without a 16alpha-nitrile group showed little or no inhibitory effect on rat liver microsomal E(1)-3-sulfatase activity. Double-reciprocal analysis showed that the inhibition of rat liver microsomal E(1)-3-sulfatase activity by PCN was essentially competitive in nature. When microsomes from six human term placentas were tested for their E(1)-3-sulfatase activity, PCN showed a similar biphasic inhibition of placental E(1)-3-sulfatase. Likewise, several of its structural analogs showed little or no inhibitory effect on placental E(1)-3-sulfatase activity. Computational analysis of the D-ring structure of PCN and other structurally similar analogs used in the study suggests that the potent sulfatase-inhibiting activity of PCN may be partly due to its unique steric orientation and size of the 16alpha-nitrile group. This knowledge may be useful for the rational design of more potent steroidal inhibitors of E(1)-3-sulfatase by introducing an additional nitrile group to their C16alpha-position.

[The effects of HCG and LHRH-A on progesterone secretion by human placenta villi cells of early and term gestation in vitro].

In the present study, the method of collagenase-pepsin prepared cell suspension of human placental villi from early (10-12 weeks) and term (38-40 weeks) gestation cultured in vitro combined with progesterone radioimmunoassay was employed. The results indicated that: 1. In the placenta villi cells from early and term gestation in vitro, both exogenous and endogenous hCG showed a stimulatory effect on progesterone secretion, and the effect was approximately proportional to the concentration of the exogenous hCG added. 2. In the placenta villi cells from term gestation in vitro, after addition of sufficient rabbit antihCG IgG to the culture medium, LHRH-A exhibited no obvious influence on this hCG-independent progesterone secretion. However, in the absence of rabbit anti-hCG IgG in the culture medium, LHRH-A showed a stimulatory action on progesterone secretion probably via its stimulatory effect on hCG secretion which could subsequently increase the progesterone secretion. 3. In the placenta villi cells from early gestation, LHRH-A exhibited an inhibitory effect on both hCG-independent and hCG-dependent progesterone secretion.

[Studies on the antipregnancy effect of LHRH-A in mid gestational rats].

In the present study, the antipregnancy effect of (D-Ala6, Pro9-Ethylamide10) LHRH (LHRH-A) on midgestation rats was observed. The results indicate that LHRH-A could terminate pregnancy of all experimented rats by abortion after subcutaneous administration of 200 micrograms LHRH-A (dissolved in vegetable oil) once a day at days 9 to 11 of their pregnancy. It was also found that the serum progesterone level was significantly lowered after the administration of LHRH-A (P less than 0.05); the concomitant administration of megestrol acetate with LHRH-A could almost completely block the antipregnancy effect of LHRH-A on the midgestation rats; LHRH-A showed a strong direct inhibitory effect on luteal cell progesterone secretion in pseudopregnant and midgestation rats. Hence, it is considered that the probable mechanisms for the antipregnancy effect of LHRH-A may be mainly due to the decrease of serum progesterone level caused by the direct inhibitory effect of LHRH-A on midgestation corpus luteum progesterone production.

[Design and synthesis of LHRH analogs].

In the hope to find new superagonists of LHRH, here we report the synthesis of six analogs by changing residue 5 of [D-Trp6 (or D-Arg6), des-Gly10]-LHRH-EA. For the convenience of comparison, the known compound [D-Trp6, desGly10]-LHRH-EA was also synthesized.

Regulation of the expression of cyclooxygenases and production of prostaglandin I2 and E2 in human coronary artery endothelial cells by curcumin.

Curcumin regulates prostaglandin (PG) synthesis in a variety of cells. PGE2 and PGI2 are generated from arachidonic acid (AA) by cyclooxygenases 1 and 2 (COX-1 and COX-2) and the synthase (PGES and PGI2S) pathways. This study evaluates the in vitro effect of curcumin on the expression of COX-1, COX-2, PGI2S and microsomal PGES-1 (mPGES-1), and the production of PGE2 and PGI2 in human coronary artery endothelial cells (HCAEC). HCAEC monolayers were incubated with curcumin and the expression of mRNA, protein and the production of PGI2 and PGE2 were quantified. Incubation of HCAEC with curcumin led to a time and concentration-dependent increases in COX-2 mRNA with a small but significant decrease in COX-1 mRNA expression. Curcumin also stimulated the expression of PGI2S and mPGES-1 mRNA. Although curcumin stimulated COX-2, PGI2S and mPGES-1 gene expression, it failed to increase PGI2 or PGE2 production. Interestingly, supplementation of the culture medium with AA increased prostanoid production by both quiescent and curcumin-treated cells. However, in comparison to the quiescent cells, the prostanoid production by curcumin-treated cells was markedly enhanced as AA concentrations in the medium were increased, and the enhanced prostanoid production was blocked by the presence of COX-2 specific inhibitor. Taken together, these results suggest that curcumin regulates prostanoid homeostasis in HCAEC by modulating multiple steps including the expression of COX-1, COX-2, PGI2S and mPGES-1.