We previously demonstrated that iodothyronine 5'-deiodination (5'D) activity is present and increased by triiodothyronine (T3) and angiotensin II (Ang II) in cultured rat cardiac myocytes. To further elucidate the stimulatory mechanism of Ang II, we investigated the effect of intracellular Ca2+ and protein kinase C on myocardial 5'D activity. Moreover, to elucidate the molecular mechanism of the stimulatory effect of T3 and Ang II, we detected the mRNA levels by means of a reverse-transcriptase polymerase chain reaction (RT-PCR). 5'D activity was increased by adding Bay-k 8644, Ca2+ channel agonist and the effect of Bay-k 8644 was completely blocked by nifedipine, a Ca2+ channel antagonist. 12-O-tetradecanoylphorbol-13-acetate, a protein kinase C activator, similarly stimulated 5'D activity. The addition of a high concentration (20-40mM) of K+, which caused the depolarization of the membrane had significant stimulatory effects on 5'D activity. Type 1 deiodinase (D1) mRNA was evident in myocardial cells by RT-PCR in a single 758bp band similar to that in the liver. Cardiac fibroblasts did not express the D1 mRNA. A significant increase in D1 mRNA was also evident after adding T3 and Ang II. These findings indicate that 5'D activity in myocardial cells is increased by activating the voltage sensitive Ca2+ channel, protein kinase C, and membrane depolarization, and that the D1 mRNA is present in cardiac myocytes and is increased by T3 and Ang II. This study therefore suggests that Ang II could affect the action of thyroid hormone on the heart by increasing the D1 gene expression.
The aim of this study was to clarify whether insulin resistance contributes to atherosclerosis in patients with non-insulin-dependent diabetes mellitus (NIDDM). Fifty-three NIDDM patients (36 males and 17 females, 53±10 years old (mean±SD)) were studied. As an index of atherosclerosis, we measured the average thickness (IMT) as well as basal thickness excluding the maximum thickness and the height of the maximum thickness of the carotid artery wall. Eugyycemic hyperinsulinemic glucose clamp was conducted for 90min to evaluate average glucose infusion rate (GIR) as an index of insulin sensitivity in the peripheral tissues. For another 180min after intake of oral glucose load with 0.3g/kg, the euglycemic hyperinsulinemic clamp was continued to measure ratio of splanchnic glucose uptake (SGU) as an index of insulin sensitivity of the liver. The patients were separated into three activity groups according to the grade of their leisure-time physical activity. GIR (r=-0.32, p<0.05) but not SGU (r=0.139) showed a significant inverse relationship with IMT. Multivariant regression analysis indicated that age and total cholesterol remain as independent risk factors for basal thickness and GIR as only independent risk factor for the height of the maximum thickness. Paralleling the degrees of habitual exercise (low, moderate, and high active group), GIR was higher (6.19±1.02, 6.38±1.38, 7.44±1.80, respectively) and IMT was lower (1.34±0.33mm, 1.20±0.31mm, and 1.12±0.29mm, respectively) in male NIDDM as well as in female NIDDM. These data suggest that insulin resistance in the peripheral tissues but not the splanchnic tissues may independently contribute to carotid arterial wall thickness and especially to plaque lesion, and that habitual exercise might reduce insulin resistance leading to attenuation of atherosclerosis.
The Wilms' tumor suppressor gene, WT1, plays an important role in the development of the urogenital system and also subsequent normal function of this system. Recently, the splice mutations in intron 9 of WT1 gene have been detected in Frasier syndrome, which is characterized by streak gonads, pseudohermaphroditism, slowly progressive nephropathy and frequent development of gonadoblastoma. Here to elucidate the molecular basis in a Japanese patient of Frasier syndrome, WT1 gene was analyzed by polymerase-chain-reaction (PCR) and direct sequencing. We identified the splice junction mutation in intron 9 of WT1, which is recognized as a mutation hot-spot in intron 9. This finding concludes that 1) the mutation in intron 9 might be the cause of Frasier syndrome, and 2) the mutation hot-spot in Japanese and Caucasian patients is similar.
We simultaneously measured the concentrations of parathyroid hormone related peptide (PTHrP) and cytokines in synovial fluid (SF) to clarify the relationship between PTHrP and cytokine network in the SF of elderly patients with arthritis. SF was collected from knee joints of five RA patients aged 66±11 years old and nine osteoarthritis (OA) patients aged 80±9 years old. PTHrP in SF was measured by enzyme-linked immunosorbent assay (ELISA), whereas tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8) in SF were all measured by ELISA. The PTHrP levels in the SF of RA patients (2.56±0.89pmol/l) were significantly (p<0.05) higher than those of OA patients (1.66±0.17pmol/l). TNF-α, IL-1β, IL-2 and IL-6 concentrations in SF of RA were also significantly higher than those in SF of OA (TNF-α 22.5±14.8vs 4.8±3.0pg/ml, p<0.01; IL-1β 11.8±11.4vs 1.4±1.3, p<0.05; IL-2 59.9±46.6vs 12.5±8.0pg/ml, p<0.05; IL-618424±8901vs 3547±2948pg/ml, p<0.01). The concentrations of IL-4 and IL-8 in SF of RA were similar to those of OA. Immunohistochemical studies revealed the presence of immunoreactive PTHrP in synovial fibroblasts from RA and OA. Among cytokines, only IL-6 was positively correlated with PTHrP levels in SF(r=0.685, p<0.01). In the culture of synovial cells from RA and OA, PTHrP was produced in RA more than OA after phorbol 12-mysistate 13-acetate (TPA) stimulation. These results indicate that PTHrP and cytokines, especially IL-6, might be involved in the inflammatory processes of elderly RA and OA. This is the first study in which PTHrP and cytokine levels were simultaneously examined in synovial fluid of elderly RA and OA.
Kallmann syndrome is defined by the association of hypogonadotropic hypogonadism and anosmia, for which three modes of transmission have been described: X-linked, autosomal recessive and autosomal dominant. The KAL1 gene, responsible for the X-linked form of the disease, has been isolated and its intron-exon organization determined. We report sequence analysis using PCR-direct sequencing method of the entire coding region and splice site junctions of the KAL1 gene in three males with Kallmann syndrome. We found a novel mutation in one case and no mutation in the other two cases. The mutation consisted of a C to T substitution in exon 1 converting codon 66 (CAG) encoding glutamine into a termination codon (TAG)/(Q66X). As a consequence of this mutation, the function of the KAL1 protein consisting of 680 amino acids was severely truncated so as to be consistent with Kallmann syndrome. As only this patient had unilateral renal hypoplasia among the three cases, this would suggest the existence of KAL1 gene mutation in this abnormality.
The objective of this study was to elucidate the mechanism underlying the further suppression of serum testosterone (T) by diethylstilbestrol diphosphate (DES-DP) in patients with prostate cancer refractory to hormonal treatment. These patients received an LHRH agonist with or without a non-steroidal androgen-receptor blocker or a gestagen before DES-DP. We measured serum levels of total and free T, dihydrotestosterone (DHT), estradiol (E2), dehydroepiandrosterone sulfate (DHEA-S), dehydroepiandrosterone (DHEA), androstenedione, cortisol, aldosterone before and during intravenous administration of high doses of DES-DP (500 or 1000mg/day). DES-DP administration suppressed the serum levels of FSH (p=0.04) and total T (p=0.02), and eliminated free T (p=0.04) and E2 (p=0.04) from serum, while reducing serum DHEA-S to approximately two-thirds of the pretreatment level (p=0.03). In contrast, serum levels of SHBG (p=0.02) and cortisol (p=0.02) were markedly increased after DES-DP administration. The latter had no significant effect on serum levels of LH, DHT, ACTH, 17α-hydroxypregnenolone, 17α-hydroxyprogesterone, DHEA, androstenedione, or aldosterone. The results suggest that the potent suppression of circulating total T by DES-DP is caused, in part, by the inhibitory effect of DES-DP on serum DHEA-S level. In most patients, high-dose DES-DP treatment completely suppressed the serum level of free T, while possibly elevating serum SHBG and decreasing serum total T. The mechanisms that maintain the serum level of serum DHT during DES-DP treatment require further elucidation.
We investigated whether thyroid status modulates serum leptin concentrations and body composition as determined by bioelectric impedance analysis (BIA). The percent body fat mass (%FM) in male Graves' disease was significantly lower than that in age- and sex- matched normal subjects, at the levels of 11.4±6.4% (mean±SD) vs 19.9±9.2% for men (n=12, P<0.05) but not for women (22.6±7.6% vs 24.9±13.1%, n=28). In contrast, in female hypothyroidism (n=11) %FM was significantly higher than that in normal subjects (32.9±11.5%, P<0.01). Among other body composition parameters, the percentage of body water (%BW), and lean body mass (LBM) were significantly lower in hypothyroid patients, and the ECM (extracellular mass)/BCM (body cell mass) ratio was significantly (P<0.0001) increased in Graves' disease which was the result of marked depletion of BCM with concomitant expansion of ECM. The serum leptin levels were significantly decreased in male Graves' patients (2.3±0.7ng/ml, P<0.05), whereas in female Graves' patients (8.8±5.9ng/ml) and patients with hypothyroidism (9.5±7.6ng/ml), the levels were not different from those of normal controls matched for BMI or %FM. There was a positive correlation between serum Leptin levels and %FM in female Graves' patients (r=0.635, P=0.001) and in hypothyroid patients (r=0.801, P=0.014) but not in male Graves patients. There was no significant relationship between serum leptin levels and thyroid hormones, TRAb, or TSAb. In euthyroid obese subjects there was a positive relationship between serum leptin levels and serum TSH levels (r=0.37, P<0.01). These results suggest that hyperthyroidism is characterized by the decreased fat mass and serum leptin levels in men, but female patients appear to be resistant to the effect of thyroid hormones. Together with previous reports, thyroid status has a minor role in the regulation of serum leptin levels.
Human thyrotropin-releasing hormone (TRH)-associated peptide 3 (hTAP-3), one of the cryptic peptides resulting from the proteolytic processing of preproTRH to produce TRH, was measured in human plasma from normal, hyperthyroid, and hypothyroid subjects. The dilution curve of hTAP-3 immunoreactivity in the serum paralleled the standard curve of the radioimmunoassay. HPLC analysis revealed a single strong immunoreactive peak, which corresponded to the authentic peptide, hTAP-3. The half-life of hTAP-3 in serum was approximately 3.5min, and the addition of aprotinin and EDTA completely prevented its degradation. In hyperthyroid patients, plasma concentrations of hTAP-3 were significantly higher than those in the control group and hypothyroid patients, but no correlation was found between its level and that of thyroid hormone. These findings indicate the existence of intact hTAP-3 in the human serum and increases in plasma hTAP-3 levels in hyperthyroid patients, suggesting that blood hTAP-3 may be derived from the peripheral organs rather than the hypothalamus.
We studied the role of phosphorus retention in parathyroid cell proliferation and parathyroid hormone (PTH) oversecretion in severe secondary parathyroid hyperplasia. Mice transplanted with human parathyroid tissue from a patient who had undergone parathyroidectomy for severe secondary hyperparathyroidism were divided into four groups; each group was given a diet with a different phosphorus content (0.4, 0.7, 1.0, and 1.2%) to alter serum phosphorus concentrations. Histologic examinations of grafts by hematoxylin-eosin or by bromodeoxyuridine (BrdU) immunohistochemical staining were performed to assess parathyroid cell proliferation. Changes in serum phosphorus concentrations unidirectionally affected PTH secretion from the graft, because human PTH did not cross-react with mouse PTH. Serum phosphorus concentrations of 1.0P and 1.2P groups were significantly higher than those of 0.4P and 0.7P groups (p<0.05). Serum phosphorus concentrations were significantly correlated with the gradient of human PTH elevation with a coefficient of 0.48 and a p<0.05. Furthermore, serum phosphorus concentrations and the gradient of human PTH elevation were significantly higher in mice with BrdU-immunoreactive cells in the parathyroid graft than in mice without immunoreactive cells in the graft. These results indicate that uncontrolled hyperphosphatemia may accelerate the proliferation of parathyroid cells, exacerbating PTH oversecretion.
We present the case of a 66-year-old woman with Hashimoto's thyroiditis, who showed extremely high concentrations of serum thyroglobulin (Tg). Serum Tg levels were markedly elevated following a slight elevation of serum thyrotropin (TSH) (22, 000ng/mL and 11.1μU/mL, respectively). Although elevated concentrations of serum Tg declined concomitant with decrease of serum TSH one month later, Tg concentrations remained high (>948ng/mL) even at normal or suppressed TSH levels. There was no evidence of massive thyroid tissue damage or thyroid tumor. To our knowledge, there have been no case reports of such high concentrations of serum Tg (>2×104ng/mL) in the clinical course of Hashimoto's thyroiditis. Furthermore, we showed evidence that extremely high Tg levels could possibly influence the measurement of anti-Tg autoantibody using highly sensitive radioimmunoassays.
Smad proteins are known to transduce signalling of TGF-β receptor superfamily. We report here the entire sequences of rat Smad2 and Smad4 which have not been identified yet. Entire sequences were identified by degenerated polymerase chain reaction and following phage library screening and 5' RACE. The predicted amino acid sequences of rat Smad2 and Smad4 are highly conserved among rat, human and mouse. We also mapped these Smads to chromosome 18q.12.3. Unlike endothelial cells, TGF-β1 stimulates articular chondrocyte proliferation as well as extracellular matrix production, and acts as a repairing agent against cartilage destruction. Since both Smad2 and Smad4 are essential factors for TGF-β signalling, we examined their expression and regulation in cultured articular chondrocytes. Northern blot analysis showed that TGF-β1 significantly increased the mRNA level of Smad2 but not of Smad4 in a dose- and time-dependent manner, suggesting that the augmentation of TGF-β1 action is caused by increasing the expression of the downstream signalling molecule.
To determine the pathophysiological implications of serum leptin level in obesity, we monitored the changes in serum leptin level during outpatient treatment with life style modification in children. Fifty-five obese Japanese children (34 boys and 21 girls; mean age, 9.64 years) were studied. The control children consisted of 42 nonobese subjects (27 boys and 15 girls). The serum leptin concentration was 4.35±0.46ng/ml (mean±SEM) in the control girls and 2.93±0.21ng/ml in the control boys. The serum leptin concentrations in the obese boys and girls were higher than those in their lean counterparts. The concentration in the obese boys (16.28±1.41ng/ml) was similar to that in the obese girls (20.33±2.0ng/ml). The logarithmic value of serum leptin concentration at the first blood sampling in obese children was correlated with percent overweight and percent body fat. In 36 obese children (24 boys and 12 girls) whose serum leptin concentrations were monitored serially during treatment of obesity, the percent overweight was significantly decreased after the initial sampling. In each individual, the changes in leptin concentration were roughly parallel to those in percent overweight. The ratio of the leptin concentration at the second blood sampling divided by the one at the first sampling in each individual was closely correlated with the respective delta percent overweight. These results suggest that the preceding course of obesity determines the serum leptin level of obese children on longitudinal basis, and that the leptin level reflects the degree of obesity on cross-sectional basis.
To elucidate the effect of pregnancy, lactation and weaning on bone mineral density (BMD) in rats, a longitudinal study was done on the same individuals measuring BMD by dual-energy X-ray absorptiometry (DXA) and comparing their profiles with those of nonpregnant controls. Twenty-seven pregnant Wistar rats which had been mated at 11 weeks old (baseline), lactated during the three weeks postpartum period and weaned thereafter. Twenty-four rats of the same age served as nonpregnant controls. BMDs in lumbar spine, distal femur and caudal spine of all rats were measured weekly from 11 to 22 weeks except for the week of parturition (14th week). During pregnancy, BMDs of the three sites increased significantly from the baseline values, but no significant difference was observed in comparison with the control. After parturition and during lactation, BMD of the three sites decreased significantly from the pregnant values and decreased even from baseline values. All the BMD values of the pregnant group were significantly lower than those of the control group. After weaning, BMDs of the three sites increased gradually and caught up to the control group at 22 weeks in the lumbar spine and the femur and at 21 weeks in the caudal spine. In conclusion, pregnancy in itself does not significantly affect maternal BMDs of rats, although the significant bone mineral loss during lactation is not completely restored until at least 5 weeks after weaning.
Insulin-like growth factor-I (IGF-I) is predominantly bound to IGF binding protein-3 (IGFBP-3), and free form of IGF-I (fIGF-I) may be bioactive in the circulation. Proteolysis of IGFBP-3, as reported in pregnant serum, results in the lowering of the affinity for IGF-I, thereby increasing the ratio of fIGF-I to total IGF-I (f/t IGF-I ratio). Conflicting results have been reported regarding the relationship between the proteolysis and growth hormone (GH)-IGF-I axis. Proteolysis of IGFBP-3 was previously reported to be present late at night in serum from pediatric subjects with GH receptor dysfunction (GHRD or “Laron-type dwarfism”). Recently, it was reported that proteolysis of IGFBP-3 could not be detected in adult patients with GH deficiency (GHD). The purpose of this study was to investigate the possible relationship between proteolysis of IGFBP-3 and GH in patients with GHD including pediatric cases. Here, proteolysis of IGFBP-3 measured by Western immunoblotting (ages 4-25 years; n=11) and f/t GF-I ratio measured by immunoradiometric assay (ages 4-25 years; n=10) were studied in patients with GHD, which is similar to GHRD in terms of lowered GH function. There was no significant proteolysis of IGFBP-3 in the sera from the 11 patients with GHD. No proteolysis of IGFBP-3 was observed during a 24 hour period in sera obtained every two hours from two patients with GHD. f/t IGF-I ratio was not increased in plasma from the 10 patients with GHD. Our data suggest that proteolysis of IGFBP-3 is independent of the GH-IGF-I axis.
Recent studies have demonstrated that troglitazone has the capacity to improve insulin resistance. The present study was undertaken to determine the effect of troglitazone on in vivo insulin action, the activities of the pyruvate dehydrogenase (PDH) complex and 3-hydroxyacyl-CoA dehydrogenase (3-HADH) in muscle, and muscle GLUT-4 and glycogen content in obese and lean Zucker rats. Rats were fed a normal chow diet with and without troglitazone as a food admixture (0.2%) for 3 weeks. In vivo insulin action was measured by the sequential euglycemic clamp technique at two different insulin infusion rates (6 and 30mU/kg BW/min). At the basal (fasting) state and after the clamp studies, the activities of PDH complex and 3-HADH, and the amounts of GLUT-4 and glycogen contained in the red gastrocnemius muscles were determined. Troglitazone treatment produced a significant rise in the metabolic clearance rate of glucose (MCR) during the 6-mU/kg BW/min insulin clamp study (19.5±3.9 vs 9.9±1.5ml/kg BW/min, mean±SE, P<0.05) in obese rats, but not in lean rats. Troglitazone significantly increased the muscle glycogen content after the clamp study, compared to non-treated rats, in obese rats (9.9±0.5vs 6.5±0.4mg/g tissue, P<0.05) and has the tendency to increase the activity state of PDH complex in obese and lean rats at the fasting state. However, no effect of the drug on muscle GLUT-4 content was found. These results indicate that troglitazone may improve insulin sensitivity associated with increased muscle glycogen content.
Thyroid follicles in the lateral position of the neck are usually thought to represent the metastasis of thyroid carcinoma. Here we present a case of a 28-year-old woman with accessory ectopic thyroid associated with Graves' disease. Despite a history of Graves' disease poorly controlled with large dose propylthiouracil she was found to be pregnant and artificial abortion was planned. Thyroid scintigraphy was carried out, which indicated an uptake into the region above the left lobe as well as into both lobes of the thyroid gland. In order to control hyperthyroidism and to exclude the possibility of metastasis, total thyroidectomy with tumor resection was performed before the artificial abortion. Pathological examinations of the thyroid gland indicated findings compatible with Graves' disease. The lateral neck mass was revealed to be composed of nonneoplastic thyroid tissue, showing similar histological findings to those of the goiter, which were consistent with Graves' disease. Taken together with several previous reports, it appears that there are some cases with lateral ectopic thyroid tissue, whose pathogenetic mechanism remains to be elucidated.
Mutations in the sex-determining gene SRY previously identified occur in the 46, XY females. In this study, we investigated whether the SRY mutation participates in the onset of XY sex reversal. Genomic deoxyribonucleic acids (DNA) from five XY sex-reversed females were analyzed for mutations in SRY using polymerase-chain reaction (PCR) amplification and subsequent DNA sequencing. One of the 46, XY females suffered a novel missense mutation at position 306 of SRY gene, wherein cytosine was replaced by adenine (CGC→AGC), resulting in a substitution of serine for arginine at amino acid position 76 of SRY protein. This mutation was located in Helix I of the high-mobility-group (HMG) domain. No other mutations were found in the remaining regions of the gene. Analysis of the SRY gene in her father revealed that he carried the identical mutation version. This substitution introduces a large basic for a small polar uncharged amino acid residue in the HMG box. The fact that the father transmits the mutant SRY copy to his offspring implies that SRY mutations do not always occur in association with sex reversal, even when the ionic environment is altered.
We present the eldest case ever reported of central diabetes insipidus (DI) associated with infundibulo- neurohypophysitis. A 77-year old woman, who complained of recent development of excessive thirst, polyuria and polydipsia, was referred to our hospital. The daily urine volume was markedly increased to 6L. DDAVP administration effectively reduced urine volume and increased urine osmolality. The loading test using high-osmolar sodium chloride showed impaired excretion of vasopressin discordant with plasma osmolar changes. The anterior pituitary function was normal. Pituitary magnetic resonance imaging (MRI) showed thickening of the pituitary stalk and a lack of high-intensity signal of the neurohypophysis on T1-weighted images, suggestive of lymphocytic infundibulo -neurohypophysitis. The thickness of pituitary stalk on MRI improved 6 months later. DI was controlled with DDAVP for 40 days. This was followed by stabilization of the daily urine volume to less than 2.5L without DDAVP. Our case is the eldest case of central DI associated with infundibulo-neurohypophysitis. The rapid remission of pituitary changes on MRI provides an insight that spontaneously partial remission of central DI may occur, resulting in transient polyuria and polydipsia.