Northern analysis of type II iodothyronine deiodinase mRNA in rat Harderian gland.

It has been known that type II iodothyronine deiodinase activity is present in rat Harderian gland and the activity is significantly increased by isoproterenol administration. We have performed Northern analyses to study whether the transcript for type II iodothyronine deiodinase is expressed in rat Harderian gland and whether the isoproterenol stimulation of type II iodothyronine deiodinase activity in rat Harderian gland is due to the change in its mRNA level. Northern analyses have demonstrated that type II iodothyronine deiodinase mRNA, approximately 7.

Primary culture of cells from hyperfunctioning thyroid adenoma with an activating mutation of G alphas.

We analyzed cultured cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue from a Japanese woman and determined the nucleotide sequences of genes encoding the alpha subunit of the stimulatory G-protein 1 (G alphas) and thyrotropin (TSH) receptor in its tumor tissue. Primary culture of cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue revealed that cAMP production was constitutively activated while intracellular Ca2+ concentration was suppressed both at the basal level and in the response to TSH stimulation in the cells from tumor tissue compared with those from non-tumor tissue. Nucleotide sequence analysis demonstrated the somatic missense mutation at codon 201 (CGT(Arg)-CAT(His)) of G alphas gene in tumor tissue but not in its surrounding tissue.

Expression and nocturnal increase of type II iodothyronine deiodinase mRNA in rat pineal gland.

It has been demonstrated that thyroxine deiodinating activity is present in rat pineal gland, and its activity increases significantly during the night time. We have studied whether mRNA for type II iodothyronine deiodinase is expressed in rat pineal gland and whether the nocturnal rise of pineal T4 deiodinating activity is due to the change in type II iodothyronine deiodinase mRNA level. Reverse transcription-polymerase chain reaction amplification and Northern blot analyses have demonstrated that type II iodothyronine deiodinase mRNA is expressed in rat pineal gland and its mRNA level increases markedly at midnight.

Decreased pulmonary perfusion in hypersensitivity pneumonitis caused by Shiitake mushroom spores.

Hypersensitivity pneumonitis is an occupational hazard of mushroom workers. We describe a patient with severe hypersensitivity pneumonitis caused by spores of the Shiitake mushroom (Lentinus edodes) who showed a marked decrease in pulmonary perfusion, as demonstrated by pulmonary scintigraphy. This patient was treated successfully with prednisolone.

Thymic hyperplasia in patients with Graves' disease. Identification of thyrotropin receptors in human thymus.

Thymic size and density were studied in 23 untreated patients with Graves' disease and 38 control subjects using computed tomography. Both thymic size and density were higher in untreated patients with Graves' disease than in control subjects in the age-matched group. After treatment with antithyroid drugs, both thymic size and density were significantly reduced, with a concomitant decrease in thyrotropin receptor antibodies.

Discrete characteristics of antibodies raised against thyrotropin receptor-related peptides whose sequences are not conserved in the luteinizing hormone/chorionic gonadotropin receptor.

In order to identify the specific regions in the human TSH receptor for TSAb and thyroid stimulation-blocking antibody (TSBAb), we produced rabbit antibodies raised against several peptides of the extracellular domain of the human TSH receptor, where sequences are not conserved in the LH/CG receptor, and measured the TSAb activity and TSBAb activity of those antibodies using Chinese hamster ovary cells expressing human TSH receptors. Only antisera from rabbits that were immunized with a peptide of amino acid 32-56, including the small insertion near the N-terminal end of the extracellular domain, showed apparent TSAb activities and have been shown to be significantly precipitated by IgG of patients with Graves' disease. TSAb activity positively correlated with the antibody titers against the peptide in those rabbits.

Nitric oxide-dependent soluble guanylate cyclase activity is decreased in platelets from male NIDDM patients.

To elucidate the underlying mechanisms of platelet dysfunction in diabetes mellitus, we examined the activity of soluble guanylate cyclase (sGC), a key enzyme in the nitric oxide (NO)-related signalling pathway, in platelets from NIDDM (non-insulin dependent diabetes mellitus) patients. The sGC activity was determined by measuring the amount of cyclic GMP produced in platelet cytosol. In the first study, we investigated the platelet sGC activity in untreated NIDDM patients without diabetic complications.

Sex and age differences in soluble guanylate cyclase activity in human platelets.

Soluble guanylate cyclase is a key enzyme of nitric oxide (NO)-related intracellular signal transduction in platelets. In the present study, we investigated the effects of sex and age on the enzyme activity in human platelets. Soluble guanylate cyclase activity was determined by generation of cyclic GMP in platelet cytosol.

Regulation of rat liver type 1 iodothyronine deiodinase mRNA levels by testosterone.

To investigate the underlying mechanisms of sex-related differences in liver type 1 iodothyronine deiodinase (ID1), we studied the sex-related differences and roles of sex steroids in liver ID1 mRNA levels in the rat. In both euthyroid and thyroidectomized rats, liver ID1 activity and ID1 mRNA levels in female rats were less than those in male rats. A positive correlation was observed between liver ID1 activity and ID1 mRNA levels.

Activation of the thyrotropin-releasing hormone (TRH) receptor by a direct precursor of TRH, TRH-Gly.

We studied the mechanism by which thyrotropin-releasing hormone (TRH)-Gly stimulated prolactin and thyrotropin (TSH) secretion in pituitary, using a pituitary mammotropic cell line, GH3 cells, and a cell line stably expressing a human TRH receptor (TRH-R). In GH3 cells expressing endogenous TRH-R, an addition of TRH-Gly evoked an immediate rise of intracellular calcium concentration, indicating that TRH-Gly reacted directly without converting from TRH-Gly to TRH. In order to determine whether this reaction might occur through TRH-R, we established a cell line stably expressing a human TRH-R, by transfecting a human TRH-R cDNA into Chinese hamster ovary cells (CHO cells).

Clinical usefulness of thyroid-stimulating antibody measurement using Chinese hamster ovary cells expressing human thyrotropin receptors.

Human thyrotropin (TSH) receptors were expressed in Chinese hamster ovary (CHO) cells using eukaryotic expression plasmid pCXN2, which contains beta-actin promoter. We measured cAMP stimulation in CHO cells expressing human TSH receptors (CHO-hTSH-R cells) by immunoglobulin G (IgG) of patients with Graves' disease and Hashimoto's thyroiditis, and compared the results with a conventional thyroid-stimulating antibody (TS-Ab) assay using porcine thyroid cells and a TSH-binding inhibiting immunoglobulin (TBII) assay. Nineteen untreated patients with Graves' disease, including a case who developed hyperthyroidism after interferon -alpha therapy for chronic hepatitis C, and 13 treated patients with Graves' disease, 10 patients with Hashimoto's thyroiditis and 8 control subjects were studied.

[TRH receptor-related signal transduction mechanism].

TRH receptor-related signal transduction mechanism in the pituitary cells and the central nervous system was reviewed. In pituitary cells, TRH binds to its specific receptor on the cell membrane, followed by hydrolysis of inositol phospholipids by activation of phospholipase C leading to an increase in inositol 1,4,5-trisphosphates (IP3) and diacylglycerol (DG). IP3 mobilizes intracellular Ca2+, which activates Ca2+ and Calmodulin dependent protein kinase (Ca-CaM kinase) and DG activates protein kinase C (PKC).

Diabetic scleredema and scleroderma-like changes in a patient with maturity onset type diabetes of young people.

A 21-year-old housewife with maturity onset type diabetes of young people developed scleredema diabeticorum, scleroderma-like skin thickness on forearms and dorsum of hands, digital sclerosis and cheiroarthropathy. She had diabetes mellitus since the age of 11 years. Her grandfather on the mother's side, her mother and 3 of 5 her mother's brothers and sisters have diabetes mellitus.

Precipitations of thyrotropin receptor-related peptides by immunoglobulin G of patients with Hashimoto's thyroiditis.

In order to study whether specific binding sites for Hashimoto's IgG exist in TSH receptor, we have examined the TSH receptor binding activity of IgG of patients with Hashimoto's thyroiditis using synthetic peptides corresponding to the amino acid sequences in the extracellular domain of human TSH receptor. Eight different peptides were synthesized, radiolabeled and examined by immunoprecipitation assay. Among the peptides studied, peptide (352-378) was significantly precipitated by IgG of patients with Hashimoto's thyroiditis compared with control subjects.

Histidyl-proline diketopiperazine. Novel formation that does not originate from thyrotropin-releasing hormone.

We asked whether cyclo(His-Pro) may arise from a substance other than the initially found progenitor thyrotropin-releasing hormone (TRH). Incubation of TRH-Gly (pGlu-His-Pro-Gly), a TRH precursor, with brain hypothalamic cytosols caused significant formation of His-Pro-Gly followed by the generation of histidyl-proline diketopiperazine (cyclo(His-Pro)), whereas TRH was not formed. The addition of purified pyroglutamyl aminopeptidase resulted in the transformation of TRH-Gly to His-Pro-Gly and cyclo (His-Pro) but not to TRH.

Pituitary adenomas of patients with acromegaly express thyrotropin-releasing hormone receptor messenger RNA: cloning and functional expression of the human thyrotropin-releasing hormone receptor gene.

We cloned a human thyrotropin-releasing hormone receptor (TRH-R) gene and its pituitary cDNA, and examined whether TRH-R mRNA may be expressed and function in the GH-secreting pituitary adenomas of patients with acromegaly. The human TRH-R consists of 398 amino acids and is a member of the G protein-coupled receptor family. The gene has a single intron in the coding sequence.

Alteration by prolonged oral administration of a thyrotropin-releasing hormone analog, TA-0910, of the pituitary-thyroid axis in subjects with brain stroke.

We evaluated whether prolonged oral administration of a novel analog of thyrotropin-releasing hormone (TRH), TA-0910, may change the pituitary-thyroid axis in human subjects with brain stroke. The subjects were given one oral dose of 2.5-20 mg of TA-0910 daily for 8 weeks, and then blood levels of TA-0910, thyroid hormones and thyrotropin (TSH) were measured.

Different posttranslational processing of human preprothyrotropin-releasing hormone in the human placenta and hypothalamus.

We scrutinized the possible existence of human prepro-THR messenger RNA (mRNA) and of its posttranslational processing products in the human placenta. Human placental mRNA of preproTRH was found to have a single species identical to that predicted from the hypothalamic mRNA, and could be reverse transcribed to complementary DNA (cDNA) encoding preproTRH in a size similar to the hypothalamic counterpart by means of reverse-transcriptase-polymerase chain reaction. Five different intervening peptides, designated human TRH-associated peptide (hTAP) [hTAP-1, preproTRH(90-111); hTAP-2, preproTRH(120-132); hTAP-3, preproTRH(141-149); hTAP-4, preproTRH(158-183); hTAP-5, preproTRH(192-224)], and a TRH precursor comprising the TRH progenitor sequence (octa-TRH) were synthesized, and six different antisera raised against individual peptides were used to develop specific RIA systems.

Characterization of human thyrotropin receptor-related peptide-like immunoreactivity in peripheral blood of Graves' disease.

An antiserum raised against an alignment of amino acid-(32-56), termed TSHRP-1, in the extracellular domain of human thyrotropin (TSH) receptor was used to identify the TSH receptor-like substance in plasma of Graves' disease. The dilution curve of plasma TSHRP-1-like immunoreactivity was observed in a manner parallel to the standard synthetic peptide curve in radioimmunoassay, and its molecular weight estimated approximately 60 kDa. The amounts of TSHRP-1-like immunoreactivity were significantly higher in Graves' plasma than those in plasma of normal and hypothyroid patients due to Hashimoto's thyroiditis.

Identification of inositol 1,4,5-trisphosphate binding in human pheochromocytoma.

An attempt was made to identify a specific binding of inositol 1,4,5-trisphosphate (IP3) to human chromaffin cell tumors. Crude microsomal fractions of pheochromocytomas possessed significant binding sites for [3H]IP3 with high- and low-affinity constants (Kd = 5.46 and 538 nM, respectively).

[Chronic lymphocytic leukemia diagnosed after corticosteroid therapy for Evans syndrome].

A 59-year-old woman was admitted in February 1991, because of abdominal distension. On admission, she had splenomegaly, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura. Evans syndrome had been diagnosed and daily prednisolone therapy had been performed.

Differential regulation of thyrotropin-releasing hormone receptor mRNA levels by thyroid hormone in vivo and in vitro (GH3 cells).

We studied the effect of thyroid status on thyrotropin-releasing hormone receptor (TRH-R) mRNA levels both in vivo and in vitro (GH3 cells) using a cloned rat TRH-R cDNA by RT-PCR. Experimental hypothyroid rats were produced by total thyroidectomy and were then killed 7 days after the operation. TRH receptor binding in the anterior pituitary and serum TSH level were elevated approximately 2-fold and 8-fold, respectively, in 7 day thyroidectomized rats.

Inhibitory effects of okadaic acid on thyrotropin and prolactin secretion from rat anterior pituitaries.

The present study was undertaken to elucidate the effects of okadaic acid, a potent inhibitor of protein phosphatases, on thyrotropin (TSH) and prolactin (PRL) secretion, and on the hydrolysis of inositol phospholipids in rat anterior pituitaries. Preincubation of anterior pituitaries with okadaic acid caused a dose dependent decrease in TRH- and K(+)-induced TSH secretion, whereas basal secretion of TSH was not affected by pretreatment with okadaic acid. In contrast, okadaic acid resulted in a marked inhibition in both basal, and TRH- and K(+)-stimulated PRL release from anterior pituitaries.