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Biomedical subjects

C Winter

Publications and source records attributed to C Winter.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effects of T'ai Chi training on function and quality of life indicators in older adults with osteoarthritis.

OBJECTIVE: To determine the effects of T'ai Chi training on arthritis self-efficacy, quality of life indicators, and lower extremity functional mobility in older adults with osteoarthritis. DESIGN: A prospective, randomized, controlled clinical trial. Intervention length was 12 weeks, with outcomes measured before and after intervention using blinded testers. Group (T'ai Chi vs Control) x time (2 x 2) mixed factorial ANOVA. SETTING: Allied Health Sciences Center at Springfield College, Springfield, MA PARTICIPANTS: A total of 33 community-dwelling participants (mean age 68) diagnosed with lower extremity osteoarthritis and having no prior T'ai Chi training longer than 2 weeks. INTERVENTION: T'ai Chi training included two 1-hour T'ai Chi classes per week for 12 weeks. MEASUREMENTS: Arthritis self-efficacy (Arthritis Self-Efficacy Scale), quality of life indicators (Arthritis Impact Measurement Scale), functional outcomes (one-leg standing balance, 50-foot walking speed, time to rise from a chair). RESULTS: T'ai Chi participants experienced significant (P < .05) improvements in self-efficacy for arthritis symptoms, total arthritis self-efficacy, level of tension, and satisfaction with general health status. CONCLUSIONS: A moderate T'ai Chi intervention can enhance arthritis self-efficacy, quality of life, and functional mobility among older adults with osteoarthritis. T'ai Chi training is a safe and effective complementary therapy in the medical management of lower extremity osteoarthritis.

Activities of Daily Living↗
PubMed1999

Proline-rich synapse-associated proteins ProSAP1 and ProSAP2 interact with synaptic proteins of the SAPAP/GKAP family.

We have recently isolated a novel proline-rich synapse-associated protein-1 (ProSAP1) that is highly enriched in postsynaptic density (PSD). A closely related multidomain protein, ProSAP2, shares a highly conserved PDZ (PSD-95/discs-large/ZO-1) domain (80% identity), a ppI domain that mediates the interaction with cortactin, and a C-terminal SAM (sterile alpha-motif) domain. In addition, ProSAP2 codes for five ankyrin repeats and a SH3 (Src homology 3) domain. Transcripts for both proteins are coexpressed in many regions of rat brain, but show a distinct expression pattern in the cerebellum. Using the PDZ domains of ProSAP1 and 2 as bait in the yeast two-hybrid system, we isolated several clones of the SAPAP/GKAP (SAP90/PSD-95-associated protein/guanylate kinase-associated protein) family. The association of the proteins was verified by coimmunoprecipitation and cotransfection in HEK cells. Therefore, proteins of the ProSAP family represent a novel link between SAP90/PSD-95 bound membrane receptors and the cytoskeleton at glutamatergic synapses of the central nervous system.

Amino Acid Sequence↗
PubMed1999

Proline-rich synapse-associated protein-1/cortactin binding protein 1 (ProSAP1/CortBP1) is a PDZ-domain protein highly enriched in the postsynaptic density.

The postsynaptic density (PSD) is crucially involved in the structural and functional organization of the postsynaptic neurotransmitter reception apparatus. Using antisera against rat brain synaptic junctional protein preparations, we isolated cDNAs coding for proline-rich synapse-associated protein-1 (ProSAP1), a PDZ-domain protein. This protein was found to be identical to the recently described cortactin-binding protein-1 (CortBP1). Homology screening identified a related protein, ProSAP2. Specific antisera raised against a C-terminal fusion construct and a central part of ProSAP1 detect a cluster of immunoreactive bands of 180 kDa in the particulate fraction of rat brain homogenates that copurify with the PSD fraction. Transcripts and immunoreactivity are widely distributed in the brain and are upregulated during the period of synapse formation in the brain. In addition, two short N-terminal insertions are detected; they are differentially regulated during brain development. Confocal microscopy of hippocampal neurons showed that ProSAP1 is predominantly localized in synapses, and immunoelectron microscopy in situ revealed a strong association with PSDs of hippocampal excitatory synapses. The accumulation of ProSAP1 at synaptic structures was analyzed in the developing cerebral cortex. During early postnatal development, strong immunoreactivity is detectable in neurites and somata, whereas from postnatal day 10 (P10) onward a punctate staining is observed. At the ultrastructural level, the immunoreactivity accumulates at developing PSDs starting from P8. Both interaction with the actin-binding protein cortactin and early appearance at postsynaptic sites suggest that ProSAP1/CortBP1 may be involved in the assembly of the PSD during neuronal differentiation.

Aging↗
PubMed1999

The presynaptic cytomatrix protein Bassoon: sequence and chromosomal localization of the human BSN gene.

Bassoon is a novel 420-kDa protein recently identified as a component of the cytoskeleton at presynaptic neurotransmitter release sites. Analysis of the rat and mouse sequences revealed a polyglutamine stretch in the C-terminal part of the protein. Since it is known for some proteins that abnormal amplification of such polyglutamine regions can cause late-onset neurodegeneration, we cloned and localized the human BASSOON gene (BSN). Phage clones spanning most of the open reading frame and the 3' untranslated region were isolated from a human genomic library and used for chromosomal localization of BSN to chromosome 3p21 by FISH. The localization was confirmed by PCR on rodent/human somatic cell hybrids; it is consistent with the localization of the murine Bsn gene at chromosome 9F. Sequencing revealed a polyglutamine stretch of only five residues in human, and PCR amplifications from 50 individuals showed no obvious length polymorphism in this region. Analysis of the primary structure of Bassoon and comparison to previous database entries provide evidence for a newly emerging protein family.

Amino Acid Sequence↗
PubMed1999

Quantification of intraocular retained perfluorodecalin after macroscopic complete removal.

BACKGROUND: A study was performed to determine the amount of intraocular retained perfluorodecalin after macroscopic complete removal. MATERIAL AND METHODS: Freshly enucleated pig eyes had the anterior segment removed, vitrectomy was carried out, and the eye cups were placed in 0.9% buffered saline solution. One millilitre of perfluorodecalin was instilled for 30 min, followed by a fluid-air exchange. Perfluorodecalin was macroscopically removed. The retina was rinsed twice with 0.9% buffered saline solution. In a second group no rinsing was done, while in a third group no fluid-air exchange was performed. Finally all eye cups were filled with 2.0 ml of the perfluoropolyether Hostinert 130 to dissolve retained perfluorodecalin. The quantity of perfluorodecalin in perfluoropolyether was determined by gas chromatography. RESULTS: Retained perfluorodecalin was detected in all experiments. The smallest portion of perfluorodecalin retained (range 0.04-0.08, mean 0.058%, SD +/- 0.015%) was observed without fluid-air exchange. After fluid-air exchange the portion with rinsing was 0.11-0.27% (mean 0.21%, SD +/- 0.059%) and that without rinsing was 0.51-0.69% (mean 0.60%, SD +/- 0.065%). CONCLUSIONS: Even after macroscopic complete removal of perfluorodecalin a thin layer remains on the retina. If intraoperative fluid-gas exchange is necessary, multiple rinsing with 0.9% buffered saline solution should be performed to reduce the amount of perfluorocarbon liquid retained.

Animals↗
PubMed1999

Optimization of terminal-restriction fragment length polymorphism analysis for complex marine bacterioplankton communities and comparison with denaturing gradient gel electrophoresis.

The potential of terminal-restriction fragment length polymorphism (T-RFLP) and the detection of operational taxonomic units (OTUs) by capillary electrophoresis (CE) to characterize marine bacterioplankton communities was compared with that of denaturing gradient gel electrophoresis (DGGE). A protocol has been developed to optimize the separation and detection of OTUs between 20 and 1, 632 bp by using CE and laser-induced fluorescence detection. Additionally, we compared T-RFLP fingerprinting to DGGE optimized for detection of less abundant OTUs. Similar results were obtained with both fingerprinting techniques, although the T-RFLP approach and CE detection of OTUs was more sensitive, as indicated by the higher number of OTUs detected. We tested the T-RFLP fingerprinting technique on complex marine bacterial communities by using the 16S rRNA gene and 16S rRNA as templates for PCR. Samples from the Northern and Middle Adriatic Sea and from the South and North Aegean Sea were compared. Distinct clusters were identifiable for different sampling sites. Thus, this technique is useful for rapid evaluation of the biogeographical distribution and relationships of bacterioplankton communities.

Animals↗
PubMed1998

Rapid and long-lasting suppression of the ATF-2 transcription factor is a common response to neuronal injury.

The activating transcription factor 2 (ATF-2) protein, a neuronal constitutively expressed CRE-binding transcription factor, is essential for the intact development of the mammalian brain. ATF-2 is activated by c-Jun N-terminal kinases and modulates both the induction of the c-jun gene and the function of the c-Jun protein, a mediator of neuronal death and survival. Here we show by immunocytochemistry and Western blotting that ATF-2 is rapidly suppressed in neurons within 1-4 h following neuronal stress such as transient focal ischemia by occlusion of the medial cerebral artery, mechanical injury of the neuroparenchym, stimulation of adult dorsal root ganglion neurons in vitro by doxorubicin as well as within 24 h following nerve fiber transection. ATF-2 reappears and regains basal levels between 12 h and 72 h following ischemia, between 50 and 100 days following axotomy, but remains absent around the site of mechanical injury during the process of degeneration. Following ischemia and tissue injury, ATF-2-IR also disappeared in areas remote from the affected brain compartments indicating the regulation of its expression by diffusible molecules. These findings demonstrate that the rapid and persistent down-regulation of ATF-2 is a constituent of the long-term neuronal stress response and that the reappearance of ATF-2 after weeks is a marker for the normalization of neuronal gene transcription following brain injury.

Activating Transcription Factor 2↗
PubMed1998

MAP kinase phosphatase 1 is expressed and enhanced by FK506 in surviving mamillary, but not degenerating nigral neurons following axotomy.

The MAP kinase phosphatase 1 (MKP-1), a dual serine-threonine phosphatase, inactivates the MAP kinases ERK and JNK/SAPK which are involved in neuronal survival and neuronal cell death following injury and degenerative stimuli. We have studied by immunocytochemistry whether regulation of MKP-1 is part of the cell-body response following nerve fiber transection. The expression of MKP-1 was investigated in axotomized neurons of the corpus mamillaris (CMm) and substantia nigra pars compacta (SNC) following transection of the mamillo-thalamic tract (MT) and the medial forebrain bundle (MFB), respectively. In contrast to the surviving CMm neurons, the vast majority of SNC neurons undergoes cell death following axotomy. MKP-1 immunoreactivity which is absent in untreated adult rats, appeared in CMm neurons 24 h following MT transection, reached a maximum after 2 days and persisted in a substantial proportion of CMm neurons until 20 days, the end of observation period. In contradistinction, MKP-1 could not be detected in the SNC neurons. MKP-1 immunoreactivity was virtually restricted to the nuclei of neurons. Subcutaneous injection of the immunosuppressant FK506 that protects axotomized SNC neurons against neuronal cell death, enhanced the expression of MKP-1 in CMm, but failed to do so in SNC neurons. The selective expression of MKP-1 in CMm is the first finding on a different regulation of components in the stress kinase signal pathway in surviving vs. degenerating axotomized neurons.

Animals↗
PubMed1998

Lasting N-terminal phosphorylation of c-Jun and activation of c-Jun N-terminal kinases after neuronal injury.

Transcription factor c-Jun is proposed to control neuronal cell death and survival, but its activation by N-terminal phosphorylation and the underlying activity of the c-Jun N-terminal kinases (JNKs) remain to be elucidated in the adult mammalian brain. We generated a polyclonal antiserum that specifically recognizes c-Jun phosphorylated at its serine 73 (S73) residue after UV irradiation of 3T3 cells. Disruption of the c-jun locus in 3T3 cells abolished this reaction, and retransfection of the human c-jun at the c-jun-/- background restored it. The phospho-c-Jun antiserum was used to visualize N-terminally phosphorylated c-Jun in the adult rat brain with cellular resolution. Prolonged c-Jun S73 phosphorylation was detected in affected neurons up to 5 d after transient occlusion of medial cerebral artery or up to 50 d after transection of central nerve fiber tracts. After cerebral ischemia-reperfusion, phosphorylation of c-Jun was linked with induced expression of Fas-ligand (APO-1, CD95-ligand), whose gene is a putative c-Jun/AP-1 target, and with terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) reactivity, a marker for apoptosis. After nerve fiber transection, however, lasting c-Jun phosphorylation occurred in axotomized neurons negative for Fas-ligand or TUNEL and regardless of degeneration or survival. In contrast to these lasting phosphorylation patterns, transient seizure activity by pentylenetetrazole provoked only a brief c-Jun phosphorylation and JNK activation. In extracts from ischemic or axotomized brain compartments, c-Jun phosphorylation correlated with enhanced long-term JNK activity, and in-gel kinase assays visualized proteins with sizes corresponding to JNK isoforms as the only c-Jun N-terminally phosphorylating enzymes. These results demonstrate that lasting c-Jun S73 phosphorylation and JNK activity are part of neuronal stress response after neurodegenerative disorders in the adult mammalian brain with Fas-ligand as a putative apoptotic effector.

3T3 Cells↗
PubMed1998

A randomised controlled trial of care of the perineum during second stage of normal labour.

OBJECTIVE: To compare the effect of two methods of perineal management used during spontaneous vaginal delivery on the prevalence of perineal pain reported at 10 days after birth. DESIGN: Randomised controlled trial. SETTING: Two English maternity care units. SAMPLE: 5471 women who gave birth between December 1994 and December 1996. METHODS: At the end of the second stage of labour women were allocated to either the 'hands on' method, in which the midwife's hands put pressure on the baby's head and support ('guard') the perineum; lateral flexion is then used to facilitate delivery of the shoulders, or the 'hands poised' method, in which the midwife keeps her hands poised, not touching the head or perineum, allowing spontaneous delivery of the shoulders. MAIN OUTCOME MEASURE: Perineal pain in the previous 24 hours reported by women in self-administered questionnaire 10 days after birth. RESULTS: Questionnaires were completed by 97% of women at 10 days after birth. 910 (34.1%) women in the 'hands poised' group reported pain in the previous 24 hours compared with 823 (31.1%) in the 'hands on' group (RR 1.10, 95% CI 1.01 to 1.18: absolute difference 3%, 0.5% to 5%, P = 0.02). The rate of episiotomy was significantly lower in the 'hands poised' group (RR 0.79, 99% CI 0.65 to 0.96, P = 0.008) but the rate of manual removal of placenta was significantly higher (RR 1.69, 99% CI 1.02 to 2.78; P = 0.008). There were no other statistically significant differences detected between the two methods. CONCLUSION: The reduction in pain observed in the 'hands on' group was statistically significant and the difference detected potentially affects a substantial number of women. These results provide evidence to enable individual women and health professionals to decide which perineal management is preferable.

Adult↗
PubMed1997

Molecular identification of a volume-regulated chloride channel.

A volume-regulated chloride current (ICl.vol) is ubiquitously present in mammalian cells, and is required for the regulation of electrical activity, cell volume, intracellular pH, immunological responses, cell proliferation and differentiation. However, the molecule responsible for ICl.vol has yet to be determined. Although three putative chloride channel proteins expressed from cloned genes (P-glycoprotein, pICln and ClC-2 ) have been proposed to be the molecular equivalent of ICl.vol, neither P-glycoprotein nor pICln is thought to be a chloride channel or part thereof, and the properties of expressed ClC-2 channels differ from native ICl.vol. Here we report that functional expression in NIH/3T3 cells of a cardiac clone of another member of the ClC family, ClC-3, results in a large basally active chloride conductance, which is strongly modulated by cell volume and exhibits many properties identical to those of ICl.vol in native cells. A mutation of asparagine to lysine at position 579 at the end of the transmembrane domains of ClC-3 abolishes the outward rectification and changes the anion selectivity from I- > Cl- to Cl- > I- but leaves swelling activation intact. Because ClC-3 is a channel protein belonging to a large gene family of chloride channels, these results indicate that ClC-3 encodes ICl.vol in many native mammalian cells.

3T3 Cells↗
PubMed1997

Cloning and expression of a brain-derived TSH receptor.

Several hormones not only regulate the activity of endocrine cells and non-endocrine tissues but also serve as neuronal transmitters or modulators of neuronal activity. Accordingly, the expression and physiological significance of hormonal receptors in the central nervous system (CNS) could be demonstrated for a whole set of hormones (e.g. hCG/LH, GH, T3, CRF, TRH). The G-protein coupled TSH receptor is densely expressed in the thyroid gland and mediates the production and secretion of thyroid hormones. Not all TSH effects, especially in neurological and psychiatric disease states, can readily be explained by the action of the hormone on the thyroid gland and/or TRH levels. Therefore, it has been suggested that TSH might exert its effects directly in the CNS, although no direct proof for a TSH receptor in the human brain has been provided yet. Here we describe the cloning of a TSH receptor from an ovine hypothalamic cDNA library that is similar to thyroid derived cDNA clones. The comparison of amino acid sequences indicates that several protein domains important for the function and activity of the receptor are highly conserved. RT-PCR and RNA protection assay demonstrated that the TSH receptor mRNA is widely expressed throughout the ovine brain. The expression of a TSH receptor in the CNS indicates that TSH is not only a hormonal messenger for the thyroid gland but can also act directly in the brain. Further studies should focus on the physiological role of TSH in the CNS and the regulation of TSH receptor expression in the mammalian brain.

Amino Acid Sequence↗
PubMed1997

Dapsone hydroxylamine inhibits the LTB4-induced chemotaxis of polymorphonuclear leukocytes into human skin: results of a pilot study.

OBJECTIVE: Dapsone (4,4'diaminodiphenylsulfone) is effective in treating leprosy, chronic inflammatory conditions and opportunistic infections in HIV patients. By the oral route, the sulfone is metabolized to monoacetyldapsone (MADDS) and dapsone hydroxylamine (DDS-NOH). We have addressed the question as to whether these dapsone metabolites have anti-inflammatory properties of their own in vivo. TREATMENT AND METHODS: After two weeks topical pre-treatment with MADDS (1%), DDS-NOH (1%) and clobetasol proprionate (CP; 0.05%) dissolved in acetone, as a reference, 10 ng leukotriene B4 (LTB4) were applied on the upper arms of eight healthy volunteers. After 24 h, biopsies were taken and the polymorphonuclear leukocytes (PMN) were quantified fluorometrically using elastase as marker enzyme. RESULTS: MADDS did not show any inhibitory activity on trafficking of PMN compared to the corresponding control and nontreated area (untreated: 790 +/- 450 PMN/10 micrograms skin; p > 0.05, acetone: 840 +/- 578 PMN/10 micrograms skin; MADDS: 1099 +/- 556 PMN/10 micrograms skin), whereas DDS-NOH caused a statistically significant inhibition of PMN accumulation as did the reference CP (DDS-NOH: 128 +/- 143 PMN/10 micrograms skin; CP: 86 +/- 131 PMN/10 micrograms skin, p < 0.01). CONCLUSIONS: These results indicate that DDS-NOH has anti-inflammatory potential which might contribute to the effectiveness of dapsone therapy.

Adult↗
PubMed1997

Expression of activating transcription factor-2, serum response factor and cAMP/Ca response element binding protein in the adult rat brain following generalized seizures, nerve fibre lesion and ultraviolet irradiation.

The expression of the constitutive transcription factors activating transcription factor-2 (ATF-2), serum response factor (SRF) and cAMP/Ca response element binding factor (CREB), and the phosphorylation of SRF and CREB were studied in the untreated adult rat nervous system and following seizure activities and neurodegenerative stimuli. In the untreated rat, intense nuclear SRF immunoreactivity was present in the vast majority of neurons in the forebrain, cortex, striatum, amygdala and hippocampus, and in some scattered neurons in the medulla and spinal cord. In contrast, SRF immunoreactivity was absent in the midline areas of the forebrain, e.g., the globus pallidum and septum, and in the hypothalamus, thalamus, mesencephalon and motoneurons. Nuclear ATF-2 was expressed at high levels in apparently all neurons, but not glial cells, throughout the neuraxis except for those neuronal populations which exhibit a high basal level of c-Jun, i.e. dentate gyrus and the motoneurons of cranial and somatosensory neurons. CREB immunoreactivity was present at a rather uniform intensity in all neuronal and glial cells throughout the neuraxis. Two hours, but not 5 h or 24 h, following systemic application of kainic acid, an increase in SRF was detectable by western blot analysis in hippocampal and cortical homogenates whereas the expression of ATF-2 and CREB did not change. Phosphorylation of CREB at serine 133 and of SRF at serine 103 were studied with specific antisera. In untreated rats, intense phosphoCREB and phosphoSRF immunoreactivities labelled many glial cells and/or neurons with the highest levels in the dentate gyrus, the entorhinal cortex and the retrosplenial cortex. Following kainate-induced seizures, phosphoSRF-IR but not phosphoCREB-IR transiently increased between 0.5 h and 2 h. Following transection of peripheral or central nerve fibres such as optic nerve, medial forebrain bundle, vagal and facial nerve fibres, ATF-2 rapidly decreased in the axotomized neurons during that period when c-Jun was rapidly expressed. SRF remained unchanged and CREB disappeared in some axotomized subpopulations. Similar to axotomy, c-Jun increased and ATF-2 decreased in cultured adult dorsal root ganglion neurons following ultraviolet irradiation. The distribution of SRF and ATF-2 suggests that their putative target genes c-fos, junB, krox-24 and c-jun can be independently regulated from SRF and ATF-2. The suppression of ATF-2 and the expression of c-Jun following axotomy and ultraviolet irradiation might be part of a novel neuronal stress response in the brain that strongly resembles the stress response characterized in non-neuronal cells.

Activating Transcription Factor 2↗
PubMed1997

Glycosylation of human bone collagen I in relation to lysylhydroxylation and fibril diameter.

Posttranslational modifications (lysylhydroxylation, glycosylation, and crosslink formation) of collagen I and the trabecular bone volume (TBV) as well as the supramolecular organization of human vertebrae were studied by analyzing vertebral bones of 55 individuals (22-93 years of age). The degree of lysylhydroxylation of both a-chains of collagen I showed a significant inverse correlation with the TBV, while only a weak correlation between lysylhydroxylation of alpha2(I) and the age of the donor was observed. The degree of glycosylation of collagen I was significantly correlated with both the level of lysylhydroxylation and the degree of osteopenia. Electron microscopic evaluation did not show any relationship between the level of collagen glycosylation and the diameter of in vivo formed fibrils or in vitro formed fibrillar aggregates. In our study the molar ratio of the mature collagen crosslinks, pyridinoline and deoxypyridinoline, showed a slight tendency to be higher, in particular in the samples with a high level of lysylhydroxylation. This ratio was recently found to be significantly increased in avian osteoporotic bone. Our data suggest that the increased level of lysylhydroxylation in human osteopenia is related to the glycosylation of collagen I, while it seems to have little impact on the formation of the mature, non-reducible collagen crosslinks investigated. Based on our observations it appears unlikely that the different diameters of collagen fibrils contribute greatly to the reduced biomechanical stability reported for overhydroxylated, osteopenic bone tissue.

Adult↗
PubMed1997

Thyrotropin expression in hypophyseal pars tuberalis-specific cells is 3,5,3'-triiodothyronine, thyrotropin-releasing hormone, and pit-1 independent.

The expression of TSH subunit genes (TSH alpha and -beta) in pituitary thyrotropes is primarily regulated via circulating thyroid hormone levels (T3) and the hypothalamic TRH. Hypophyseal pars tuberalis (PT)-specific cells also express both hormonal subunits of TSH, but do not resemble thyrotropes of the pars distalis (PD) with respect to their distinct morphology, secretion, and direct modulation of TSH expression by photoperiodic inputs and melatonin. To investigate whether this distinct regulation of TSH is related to a different molecular structure or different signaling cascades, we analyzed PT-specific TSH and its transcriptional regulation in ovine PT-specific cells. After construction of PT- and PD-specific complementary DNA (cDNA) libraries, the cloning and sequencing of several TSH alpha and -beta subunit clones revealed identical sizes and sequences for the translated and untranslated regions in both hypophyseal compartments. Transcription start site analysis also displayed three identical start sites for the transcription of TSH beta in PT and PD. After cloning of the ovine TRH receptor cDNA and a partial T3 receptor cDNA, in situ hybridization. Northern blot analysis, and PCR experiments showed that TRH and T3 receptors are not expressed in specific cells of the PT. The transcription factor Pit-1 that is involved in TSH expression of thyrotropes could only be detected in the PD. In additional experiments rats were treated with T4 or TRH, and subsequent in situ hybridization studies showed that TSH beta messenger RNA (mRNA) formation was not altered in the PT. In the PD, however, TSH beta mRNA was significantly reduced in the T4-treated group, but was enhanced in the TRH-treated group. We conclude that PT-specific cells of the pituitary are characterized by the transcription of TSH subunits that are identical to TSH expressed in thyrotropes of the PD. The absence of TRH, T3 receptor mRNA, and Pit-1, respectively, as well as the different reactions compared to PD thyrotropes in in vivo experiments lead to the conclusion that the expression of TSH in PT-specific cells of the pituitary is not regulated via the classical thyrotrope receptors and their intracellular pathways, but through a novel, photoperiod-dependent mechanism.

Animals↗