Transcriptional regulation of human thyroid hormone receptor beta 1 gene expression: effect of human retinoid X receptor and identification of a transcriptional silencer region

Effects of human retinoid X receptor alpha (hRXR alpha) and its ligand, 9-cis-retinoic acid, on T3-mediated auto-regulation of hTR beta 1 gene expression were examined using a chloramphenicol acetyltransferase (CAT) reporter system, and a deletional analysis of the promoter. hRXR alpha enhanced T3-dependent CAT induction mediated through the proximal (p) TRE in a ligand (9-cis-retinoic acid) independent manner. In a gel mobility shift assay, hRXR alpha enhanced the binding of hTR beta 1 to the pTRE by the formation of hRXR alpha-hTR beta 1 heterodimers. On the other hand, hRXR alpha and 9-cis-retinoic acid did not show any effects on T3-dependent CAT induction mediated through the distal (d) TRE or the binding of hTR beta 1 to the dTRE. A four hundred-base pair (bp) fragment adjacent upstream of the dTRE showed a T3 independent suppressor effect on the function of the pTRE and dTRE. Thus, this region may be an important regulator of the T3 dependent up-regulation of the TR beta 1 gene expression which is observed only under specific conditions.

Remnant-like lipoproteins stimulate whole blood platelet aggregation in vitro

We have developed a simple, rapid assay method to measure remnant-like lipoproteins by using an immunoaffinity gel mixture of anti apo B-100 and apoA-1 antibodies to Sepharose 4B. Characterization of the unbound lipoproteins has shown that they represent chylomicron and VLDL remnant particles (RLP). Preincubation of whole blood with RLP resulted in the enhanced activation of aggregation with ADP and collagen. Such enhancement was not observed in the presence of lipoprotein deficient serum or albumin preparation. The extent of enhancement was 2.78 times by 7.5 microM of ADP and 44 times by 0.5 microgram/ml of collagen in the presence of RLP-preparation 1 (RLP-1), respectively. In the presence of RLP-2, the enhancement was 5.37 times by 7.5 microM of ADP and 102 times by 0.5 microgram/ml of collagen, respectively. On the other hand RLP slightly inhibited PRP aggregation by these agonists. Inhibitions were 19% by 7.5 microM of ADP and 18% by 1.0 microgram/of collagen in the presence of RLP-1, respectively. Incubation of whole blood with RLP did not result in the release of factors to stimulate platelets or ADP- or collagen-induced platelet aggregation in vitro. The extents of enhanced aggregation in whole blood or inhibition in PRP were not correlated with RLP-cholesterol nor RLP-protein concentrations of RLP preparations used. These results may indicate that RLP not only interact with platelets but with erythrocytes or leukocytes. Our findings support the hypothesis that the postprandial increase in remnant lipoproteins is an atherosclerotic risk factor and may be a part of the reasons of thrombotic complications by stimulating platelets in patients with remnant hyperlipoproteinemia.

Prominent uptake of Tl-201 by duodenal leiomyosarcoma after exercise myocardial perfusion study

Thallium-201 SPECT performed preoperatively for the evaluation of myocardial ischemia in a 72-year-old man with duodenal leiomyosarcoma demonstrated prominent focal uptake in the abdomen. Comparing a transaxial slice of SPECT through the abdominal uptake to the CT scan, the uptake was confirmed to be corresponding to the tumor. The tumor was delineated clearly, in good contrast to the surrounding normal intestine, which showed far less Tl-201 uptake than the tumor. In the delayed SPECT performed 3 hours after injection, although the intestinal activity became perceptible, the tumor still could be differentiated from the surrounding normal intestine. In this case, the exercise might be attributable to the initial low Tl-201 uptake by the normal intestine, which might otherwise have been an obstacle to Tl-201 scintigraphy for abdominal tumor detection. This case suggests the use of exercise for avoiding unfavorable intestinal activity, and the possibility of Tl-201 SPECT for abdominal tumor imaging.

The morphology and innervation of the lateral pterygoid muscle of the dog

The number of heads possessed by the lateral pterygoid muscle was investigated in the dog. Only a single head was observed which it is suggested may correspond to the lower head in other mammals. It inserted both onto the condyle and into the articular disc. The nerve which innervated this muscle arose directly from the mandibular nerve, separate from the medial pterygoid nerve. Because of this, it should be termed the lateral pterygoid nerve and not the pterygoid nerve.

[Value of 123I-BMIPP scintigraphy in patients with ischemic heart disease: comparison with exercise 201Tl SPECT]

To evaluate 123I labeled beta-methyl-branched fatty acid (BMIPP) myocardial uptake at rest in the segment with and without stress induced ischemia in patients with coronary artery disease, 123I-beta-methyl-branched fatty acid myocardial scintigraphy was performed at rest and was compared with the findings of stress-reinjection 201Tl myocardial scintigraphy in 31 patients with coronary artery disease. In 159 ischemic myocardial segments, equally decreased uptake on both reinjection 201Tl and fatty acid images was observed in 64 segments, more severely decreased uptake of fatty acid in 76 segments, and more severely decreased uptake of reinjection thallium in 19 segments. On the other hand, in 53 non-reversible defects, each patterns was observed in 41, 3, and 9 segments respectively. When comparing the ischemic segments with more reduced uptake of fatty acid than reinjection thallium (Group 1) and the ischemic segments with equally or less reduced fatty acid uptake than reinjection thallium (Group 2), wall motion was more severely impaired in Group 1 than in Group 2 (severe hypo- to dyskinesis was present in 32 of 54 segments in group 1 and in 21 of 75 segments in group 2, p < 0.005). In conclusion, in patients with coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection 201Tl in the segments with stress induced ischemia and wall motion was more impaired in these segments. BMIPP myocardial imaging may provide information on metabolic alterations at rest independent of perfusion abnormalities in patients with coronary artery disease.

Pharmacological study of stem-cell-factor-induced mast cell histamine release with kinase inhibitors

Stem cell factor (SCF) is a ligand for c-kit receptor and has a critical role in the development of mast cells. In this study, we investigated the effect of a panel of kinase inhibitors on SCF-induced histamine release from rat peritoneal mast cells. Genistein, an inhibitor of tyrosine kinases, inhibited SCF-induced histamine release with IC50 of 1.6 x 10(-5) M. Wortmannin, an inhibitor of phosphatidylinositol 3'-kinase (PI3 kinase), inhibited histamine release stimulated with SCF dose-dependently with IC50 of 4 x 10(-9) M. KT5926, an inhibitor of myosin light chain (MLC) kinase, reduced histamine release with IC50 of 1.8 x 10(-7) M. Staurosporine, an inhibitor of protein kinases, also inhibited SCF-induced histamine release with IC50 of 6.5 x 10(-8) M. These results show the early involvement of tyrosine kinase and PI3 kinase and the possible role of MLC kinase in the late secretory phase in the signaling pathway used by SCF.

Arg-vasopressin content in the suprachiasmatic nucleus of rat pups: circadian rhythm and its development

To investigate the development of Arg-vasopressin (AVP) content and its diurnal rhythm in the suprachiasmatic nucleus (SCN), AVP was measured by enzyme immunoassay in the rat pup SCN punched out from tissue slices obtained at postnatal day (PD) 1, 5, 10, 12 and 20 from animals maintained under a light-dark cycle (LD). The AVP levels, measured at a restricted time of day, increased from PD1 reaching the adult level at PD10-12. Diurnal rhythm similar to that in adults was evident at PD10-12 under the LD conditions used. The peak value of AVP was observed at the earlier light period, and its trough occurred at the end of the light period. The circadian rhythm remained for 7 days under constant dark (DD) or constant light (LL) conditions. These results indicate that the AVP, one of the output signals from the SCN, starts to oscillate after PD10-12, and shows a free-running rhythm during the nursing period.

[Evaluation of myocardial fatty acid metabolism in the area of fill-in after thallium reinjection in patients with prior myocardial infarction]

Myocardial fatty acid utilization in the area with thallium fill-in after reinjection was assessed using 123I-labeled 15-(p-iodophenyl)3R,S-methylpentadecanoic acid (BMIPP). We studied 22 patients with prior myocardial infarction that revealed persistent defects on standard exercise-redistribution thallium imaging. In each patient, exercise-redistribution-reinjection thallium imaging was performed. Within two weeks of the thallium study, resting BMIPP imaging was performed 20 min after injection of BMIPP (148 MBq). Following qualitative analysis of the obtained thallium and BMIPP images, quantitative analysis was performed on the basis of relative regional uptake. Of 199 myocardial segments that showed persistent defects on exercise-redistribution images, 73 segments showed apparent fill-in on the reinjection images (fill-in positive), and the remaining 126 segments did not (fill-in negative). When BMIPP images were compared with the corresponding thallium reinjection images, reduced BMIPP uptake compared with thallium were frequently observed in the area of fill-in positive segments (65 of 73 segments, 89%). Quantitative analysis also showed decrease in BMIPP activity compared to thallium activity in the area of fill-in (49.7 +/- 16.1 vs. 65.8 +/- 16.0%, p < 0.001). In contrast, only 24 of the 126 fill-in negative segments (19%) showed lower BMIPP uptake than thallium. These results suggest that impaired fatty acid utilization in the area of thallium new fill-in after reinjection already exists at resting condition.(ABSTRACT TRUNCATED AT 250 WORDS)

[Spatial and temporal alteration of the dual supply of the hepatic circulation with transient occlusion of the hepatic veins: spiral volumetric CT during arterial portography and arteriography]

To elucidate the contribution of hepatic veins to the blood flow of liver, CT arterial portography and/or arteriography was performed in eight patients having hepatocellular carcinoma with transient occlusion of the hepatic vein and eight without occlusion. In each patient with occlusion of the hepatic vein, CT showed a well-demarcated fan-shaped area of low density during arterial portography and increased density during arteriography in the corresponding area. Hepatic vein occlusion could result in the pooling of arterial blood in the liver parenchyma. Transient segmental hepatic venous occlusion might improve the results of transcatheter arterial infusion and transcatheter arterial embolization for liver tumors.

Variable portal circulation from inferior mesenteric vein assessed by per-rectal radionuclide administration

The intrahepatic distribution of radioactivity after the per-rectal administration of 201T-chloride and/or 99Tcm-pertechnetate was investigated in 177 studies in 149 patients with no liver disease or diffuse liver disease and compared with that of 99Tcm-stannous (99Tcm-Sn) colloid scintigrams. The patients were classified into two groups: distribution of intrahepatic radioactivity of 201Tl and/or 99Tcm-pertechnetate scintigrams similar to (homogeneous) or different from (heterogeneous) that of 99Tcm-Sn-colloid scintigrams. The heterogeneous group was divided into three subgroups: increased radioactivity of the right lobe (right dominant pattern), increased radioactivity of the left lobe (left dominant pattern) and uneven distribution of radioactivity in both lobes (uneven pattern). Of the 80 patients in whom the studies were performed in the supine position at rest, 14 (17.5%) showed a heterogeneous pattern (8 right dominant, 4 left dominant, 2 uneven) and 66 (82.5%) a homogeneous pattern. In the 97 patients allowed free body movement, 6 (6.2%) showed a heterogeneous (1 right dominant, 5 left dominant) and 91 (93.8%) a homogeneous pattern. A significant difference in the incidence of heterogeneous distribution between the resting and free body movement groups was found (P < 0.05). One patient with a left dominant pattern after free body movement with 201Tl showed a right dominant pattern at rest in the 99Tcm-pertechnetate study. It is concluded that a heterogeneous intrahepatic distribution of inferior mesenteric vein blood is sometimes observed and that the distribution of portal vein blood flow seems to be affected by the patient's positioning and free body movement.

o-, m- and p-hydroxybenzoate degradative pathways in Rhodococcus erythropolis

Rhodococcus erythropolis strain S1 uses the gentisate pathway to metabolize salicylate and m-hydroxybenzoate and the protocatechuate pathway to degrade p-hydroxybenzoate. m-Hydroxybenzoate 6-hydroxylase was induced by growth on m-hydroxybenzoate or gentisate, and salicylate 5-hydroxylase only by growth on salicylate. p-Hydroxybenzoate 3-hydroxylase could be induced only by growth on p-hydroxybenzoate. m-Hydroxybenzoate or p-hydroxybenzoate could repress the induction of salicylate 5-hydroxylase. Maleylpyruvate isomerase in the gentisate pathway did not require reduced glutathione.

Serum triglycerides and blood coagulation factors VII and X, and plasminogen activator inhibitor-1

It has been suggested that impaired fibrinolytic-coagulation system, such as increased concentration of inhibitors to fibrinolysis or activators to coagulations, occasionally may play a role in the development of atherosclerotic vascular disease. In this study, we aimed to elucidate the relationship of serum lipids to fibrinolytic-coagulation system. The subjects studied were 190 outpatients at Kyorin University Hospital, 108 of whom were mostly hypertension, diabetes mellitus and hyperuricemia (Control), 59 of whom were coronary heart disease (CHD), 25 of whom were cerebrovascular disease (CVD). Blood samples were measured the levels of blood coagulation factors VII (F-VII) and X (F-X), and plasminogen activator inhibitor-1 (PAI-1) in these subjects, together with the concentrations of serum lipids. The serum levels of F-X was significantly higher in CHD subjects than in controls (111 +/- 19% vs 101 +/- 22%, p < 0.05). However, there was a no significant difference of F-VII among three groups. And we found that the levels of serum lipids, especially serum triglycerides showed a significant positive correlation between the concentrations of F-VII (r = 0.343, p < 0.01) and F-X (r = 0.513, p < 0.01), and PAI-1 (r = 0.528, p < 0.001) in CHD and CVD subjects. For this reason, 156 bank employee subjects were also admitted to this study (Bank employees). In bank employee subjects, the serum levels of triglycerides also showed a significant positive correlation with the levels of F-VII (r = 0.321, p < 0.001), F-X (r = 0.254, p < 0.001) and PAI-1 (r = 0.420, p < 0.001). These data suggest that serum lipids, particularly triglycerides have a close relationship with thrombogenesis as evidenced by activated F-VII and F-X in the extrinsic coagulation system and also by elevated PAI-1 activities in fibrinolysis. Therefore, when we try to prevent the patients from CHD or treat them, we ought pay attentions not only to serum cholesterol or LDL-cholesterol for their atherogenic actions, but also to triglycerides because of their close correlation with extrinsic coagulation system and anti-fibrinolytic activities. The reduction of fibrinolytic capacity due to increased plasma levels of F-VII, X and PAI-1 may have importance in atherosclerotic vascular disease, particularly in patients with hypertriglyceridemia.

Hypertriglyceridemia and fatty liver: clinical diagnosis of fatty liver and lipoprotein profiles in hypertriglyceridemic patients with fatty liver

Fatty liver has prevailed by 14% in the healthy population of this country. The factors contributing genesis of fatty liver were gender (male), obesity, high alcohol consumption, glucose intolerance and hypertriglyceridemia. And hypertriglyceridemia seems to be the common underlying factor to all other causes. The mechanism for accumulation of triglycerides in the liver can be explained at least by increased HTGL activities and elevated apo A-II levels, a postulated co-factor of HTGL. An hypertriglyceridemic patients with fatty liver had the insulin resistance.

Structure-activity relationship of adrenomedullin, a novel vasodilatory peptide, in cultured rat vascular smooth muscle cells

Vascular smooth muscle cells (VSMC) from rat aorta possess specific receptors for a novel potent vasorelaxant peptide, adrenomedullin (AM). To elucidate its receptor coupling to guanine nucleotide-binding stimulatory protein and the structural requirement of the AM molecule to its vascular receptors, we have studied the effects of guanine nucleotides on [125I]human (h) AM binding and adenylate cyclase activity in cultured rat VSMC, and the effects of various synthetic hAM analogs on [125I]hAM binding and the cAMP response. Guanosine 5'-O-(3-thiotriphosphate) dose dependently inhibited [125I]hAM binding to rat VSMC membranes. hAM stimulated adenylate cyclase activity, and its effect was additive with GTP. hAM-induced cAMP formation was abrogated by pretreatment with cholera toxin, but not by that with pertussis toxin. Intact hAM-(1-52)-NH2 and N-terminal truncated derivatives [hAM-(13-52)-NH2, hAM-(16-52)-NH2] almost equally inhibited [125I]hAM binding and stimulated cAMP formation, whereas removal of C-terminal Tyr52 residue [hAM-(1-51)-NH2] remarkably decreased receptor-binding activity and the cAMP response. The effects of hAM-(1-52)-OH, hAM-(1-51)-OH, and a linear hAM analog ([carbamoylmethyl-Cys16,21]hAM-NH2) were far less potent on receptor binding and the cAMP response than that of hAM-(1-52)-NH2. The C-terminal fragment [hAM-(33-52)-NH2] and the N-terminal fragment [hAM-(1-10)-OH] had neither receptor-binding nor adenylate cyclase activity. hAM-(22-52)-NH2 had no agonistic effect, but showed an antagonistic effect on the hAM-induced cAMP response. These data suggest that vascular AM receptors are functionally coupled to adenylate cyclase via guanine nucleotide-binding stimulatory protein. Studies of the structure-activity relationship of hAM revealed that the cyclic structure formed by the disulfide bridge and amidation of the C-terminal residue of the AM molecule are critical for receptor binding and subsequent cAMP generation and suggest that the C-terminal fragment hAM-(22-52)-NH2 may be an antagonist for vascular AM receptors.

Metallothionein in human seminal plasma

Metallothionein (MT) concentrations were measured in the seminal plasma of 4 fertile and 35 infertile men and in the hydrocele and spermatocele fluids. The relationship between MT content and sperm density, total number of sperm per ejaculate, sperm motility and abnormal form rates, leukocyte count and zinc levels in seminal plasma, as well as the relationship between MT and serum follicle-stimulating hormone, luteinizing hormone, testosterone, and prolactin were examined. MT was not detected in the hydrocele and spermatocele fluids. MT levels were related to zinc levels and to the leukocyte count in seminal plasma, but there was no correlation between MT and the other factors examined. This study supported previous findings that MT was secreted predominantly from the prostate and induced by inflammation of the prostate gland or seminal vesicles; the findings suggest that MT binds mainly to zinc and is one of the zinc-binding proteins in seminal plasma.

Plasminogen binds specifically to alpha-enolase on rat neuronal plasma membrane

Plasminogen (PGn) that we identified in microglial-conditioned medium has a neurotrophic factor-like effect on cultured neurons. We have also shown that PGn binds specifically to a protein with a molecular mass of 45 kDa in the neuronal plasma membrane. As a candidate PGn receptor-like molecule on the neuronal surface, this 45-kDa protein was purified from the plasma membrane of embryonic rat brain. Amino acid sequence analysis of polypeptides derived from the cleavage of the protein with cyanogen bromide and V8 protease revealed that the 45-kDa protein is identical to rat alpha-enolase. In fact, PGn was found to bind to purified rat alpha-enolase and also to a synthetic peptide (30 residues) that corresponds to the carboxyl terminal region of rat alpha-enolase. Physical properties of the 45-kDa protein, such as molecular mass, isoelectric point, and the ability to form dimers, are quite similar to those of alpha-enolase. The 45-kDa PGn-binding protein in the plasma membrane was also recognized by anti-rat alpha-enolase antibody, and pretreatment with alpha-enolase antibody markedly diminished the PGn-binding to the plasma membrane. In addition, immunocytochemical staining of the cultured cells under the nonpermeable condition showed that alpha-enolase is present on the cell surface of a certain population of neurons. These results suggest that alpha-enolase may function as a PGn-binding molecule on the neuronal cell surface.

Left ventricular functional reserve in nonobstructive hypertrophic cardiomyopathy: evaluation by continuous left ventricular function monitoring

The cardiac functional response to exercise in patients with nonobstructive hypertrophic cardiomyopathy (HCM) was evaluated using a continuous ventricular function monitor with a cadmium telluride detector (CdTe-VEST).

METHODS

Supine ergometric exercise was performed under CdTe-VEST monitoring in 41 patients with nonobstructive HCM (34 men and 7 women, age 18-72 yr, mean 51 yr) and 15 patients without cardiac disease (9 men and 6 women, age 36-56 yr, mean 49 yr).

RESULTS

Although 20 of 41 patients with HCM maintained a LVEF above baseline at peak exercise (Group A), 21 did not show an EF increase at peak exercise (Group B). Exercise duration and work load in Group A were longer and higher, respectively, than in Group B. Resting EF in Group B (72 +/- 7.7%) was significantly higher than that in Group A (65 +/- 8.2%) and the control group (62 +/- 5.9%). The EF increase from baseline to EF overshoot during recovery and the time to EF overshoot were lower and longer, respectively, in Group B than in Group A and the control group. Septal wall thickness and the septum-to-posterior-wall-thickness ratio between Groups A and B were not different. ST-segment depression was observed in all 21 Group B patients and in 8 of the Group A patients.

CONCLUSION

In patients with nonobstructive HCM, left ventricular dysfunction during exercise and during recovery was frequently observed but was not related to the degree of septal wall hypertrophy. The CdTe-VEST is a useful means to evaluate left ventricular functional reserve to exercise in patients with HCM.

Rainbow trout ventricular natriuretic peptide: isolation, sequencing, and determination of biological activity

Ventricular natriuretic peptide (VNP) is a new type of cardiac natriuretic peptide initially isolated from the eel ventricle. VNP has been isolated from cardiac ventricles of the rainbow trout, Oncorhynchus mykiss, and found to consist of 35 amino acid residues carrying a C-terminal tail sequence with 14 amino acid residues. Thus, the long C-terminal sequence characteristic of VNP was also conserved in the trout VNP. A VNP with 4 amino acid residues truncated from the C-terminus was also isolated from trout ventricles and sequenced. Sequence identity of trout VNP to eel VNP was 77%; while it was 56% to eel A-type natriuretic peptide (ANP). Trout VNP caused characteristic biphasic vasopressor/depressor effects in the trout similar to those produced by rat and eel ANP. Trout VNP and human ANP were almost equipotent in their vasopressor and depressor activity in trout. Unlike eel VNP, therefore, homologous VNP did not exhibit greater activity in the trout. In the rat, however, trout VNP was more potent than eel peptide and was almost equipotent to human ANP for both vasodepressor and natriuretic effects. The high potency of trout VNP appears to be due in part to its longer-lasting effect compared to human ANP.

[Clinical trials of TAE using micro-coil coated with n-butyl 2-cyanoacrylate and lipiodol]

Clinical trials of TAE using microcoils (Target, USA) coated with n-butyl 2-cyanoacrylate and lipiodol were performed. The procedures were as follows. First, a small amount of lipiodol was injected into a Tracker 18 catheter. Secondly, a microcoil coated with n-butyl 2-cyanoacrylate and lipiodol was inserted into the microcatheter. Thirdly, a small amount of lipiodol was again administered into the catheter just behind the coil. Finally, the coil was pushed safely out from the catheter with a special guidewire. With this method, excellent occlusion of small arteries was obtained. There were no complications.

E1A repression of IL-6-induced gene activation by blocking the assembly of IL-6 response element binding complexes

Some viral products interfere with host antiviral defense mechanisms. Adenovirus E1A represses IFN signal transduction pathways which induces gene activation and an antiviral state. Both IFN and IL-6 activate Jak/Tyk protein tyrosine kinases and the STAT (signal transducer and activator of transcription) family proteins. We showed that 12S E1A repressed IL-6 signals activating the junB promoter and the two IL-6 response elements (REs), JRE-IL6 and type II IL-6 RE (also called acute phase response element), required for IL-6-induced activation of the junB promoter and the type II acute phase reactant genes, respectively, in hepatocytes. Conserved region 1 of the 12S E1A was responsible for the repression. Target molecules of the repression by E1A appeared to be IL-6-inducible DNA-binding proteins acting on the IL-6 REs. In a rat 3Y1 cell line stably expressing E1A, the levels of IL-6-induced IL-6 RE binding proteins were severely reduced compared with those in a parental 3Y1 cell line. Moreover, we found that the levels of the STAT family proteins including Stat1-alpha (p91), Stat1-beta (p84), Stat2 (p113), and Stat3 were decreased by the stable expression of adenovirus E1A. The E1A-induced reduction in the amount of DNA-binding proteins seemed to be partly responsible for the decreased transcriptional activity of the IL-6 RE-driven gene expression in response to IL-6. This repression mechanism may be applicable to the E1A repression of IFN-gamma-induced gene activation.

E1A repression of IL-6-induced gene activation by blocking the assembly of IL-6 response element binding complexes

Some viral products interfere with host antiviral defense mechanisms. Adenovirus E1A represses IFN signal transduction pathways which induces gene activation and an antiviral state. Both IFN and IL-6 activate Jak/Tyk protein tyrosine kinases and the STAT (signal transducer and activator of transcription) family proteins. We showed that 12S E1A repressed IL-6 signals activating the junB promoter and the two IL-6 response elements (REs), JRE-IL6 and type II IL-6 RE (also called acute phase response element), required for IL-6-induced activation of the junB promoter and the type II acute phase reactant genes, respectively, in hepatocytes. Conserved region 1 of the 12S E1A was responsible for the repression. Target molecules of the repression by E1A appeared to be IL-6-inducible DNA-binding proteins acting on the IL-6 REs. In a rat 3Y1 cell line stably expressing E1A, the levels of IL-6-induced IL-6 RE binding proteins were severely reduced compared with those in a parental 3Y1 cell line. Moreover, we found that the levels of the STAT family proteins including Stat1-alpha (p91), Stat1-beta (p84), Stat2 (p113), and Stat3 were decreased by the stable expression of adenovirus E1A. The E1A-induced reduction in the amount of DNA-binding proteins seemed to be partly responsible for the decreased transcriptional activity of the IL-6 RE-driven gene expression in response to IL-6. This repression mechanism may be applicable to the E1A repression of IFN-gamma-induced gene activation.