Search results for "thyroid hormone"
showing 10 items of 166 documents
Dissimilar PTH, Gastrin, and Calcitonin Responses to Oral Calcium and Peptones in Hypocalciuric Hypercalcemia, Primary Hyperparathyroidism, and Norma…
2005
We analyzed gastrin, PTH, and calcitonin responses to oral calcium and peptones in hypocalciuric hypercalcemia, mild primary hyperparathyroidism, and normal controls. We observed diverse hormonal responses that may help in the differential diagnosis of these conditions. Introduction: Hypocalciuric hypercalcemia (HH) is consequent to calcium-sensing receptor (CaSR) genetic mutations or anti-CaSR antibodies. CaSR is expressed in parathyroid tissue, thyroid C cells, and gastrin-secreting cells, where it has been suggested that on calcium and/or amino acid allosteric activation, promotes gastrin secretion. Materials and Methods: We evaluated gastrin, PTH, and calcitonin responses to oral calciu…
Increased Gastrin and Calcitonin Secretion after Oral Calcium or Peptones Administration in Patients with Hypercalciuria: A Clue to an Alteration in …
2005
The calcium-sensing receptor (CaSR) has been detected in human antral gastrin-secreting cells, where, upon calcium and/or amino acid allosteric activation, it stimulates gastrin secretion. Patients with absorptive hypercalciuria (AH) display an enhanced gastric acid output; therefore, we evaluated the secretion of gastrin in subjects with AH ( 30 subjects vs. 30 healthy female controls, all postmenopausal) after oral calcium administration ( 1 g calcium gluconate) and, on a separate occasion, after peptone loading test ( protein hydrolyzed, 10 g). Gastrin and monomeric calcitonin responses were higher in AH after both oral calcium administration ( P < 0.01) and peptone loading ( P< 0.01). B…
Mid-region parathyroid hormone-related protein (PTHrP) binds chromatin of MDA-MB231 breast cancer cells and isolated oligonucleotides “in vitro”
2006
We have previously shown that PTHrP(38-94)-amide restrains growth and invasion "in vitro", causes striking toxicity and accelerates death of some breast cancer cell lines, the most responsive being MDA-MB231 whose tumorigenesis was also attenuated "in vivo". PTHrP(38-94)-amide contains the domain implicated in the nuclear import of PTHrP. Although the nucleus was identified as a destination for mid-region PTHrP, evidence for direct DNA-binding capability is lacking to date. Here, we examined the localization of PTHrP(38-94)-amide within MDA-MB231 cells and within metaphase spread preparations and characterized its DNA-binding properties, employing a combination of immunocytochemical, cytoge…
Parathyroid Hormone-Related Protein (PTHrP): A Key Regulator of Life/Death Decisions by Tumor Cells with Potential Clinical Applications
2010
Parathyroid hormone-related protein (PTHrP), classically regarded as the mediator of the humoral hypercalcemia of malignancy syndrome, is a polyhormone that undergoes proteolytic processing into smaller bioactive forms. These bioactive forms comprise an N-terminal- as well as midregion- and C-terminal peptides, which have been shown to regulate various biological events, such as survival, proliferation and differentiation, in diverse cell model systems, both normal and pathological. A number of experimental data have demonstrated that PTHrP is also able to modulate tumor-relevant phenotypic expressions, thereby playing a role in early and advanced tumorigenesis, and in the response to treat…
Midregion PTHrP regulates Rip1 and caspase expression in MDA-MB231 breast cancer cells.
2007
It was previously reported that the midregion PTHrP domain (38-94)-amide restrains growth and invasion "in vitro", causes striking toxicity and accelerates death of some breast cancer cell lines, the most responsive being MDA-MB231 whose tumorigenesis was also attenuated "in vivo". In addition, we have demonstrated that midregion PTHrP is imported in the nucleoplasm of cultured MDA-MB231 cells, and that "in vitro" it can bind chromatin of metaphase spread preparations and also an isolated 20-mer oligonucleotide, thereby appearing endowed with a putative transcription factor-like DNA-binding ability. Here, we examined whether PTHrP (38-94)-amide was able to modulate the expression of genes e…
Transforming growth factor-β1, β2, and β3, urokinase and parathyroid hormone-related peptide expression in 8701-BC breast cancer cells and clones
1993
8701-BC is a recently characterized cell line isolated from a primary ductal infiltrating carcinoma of the breast (d.i.c.), showing some pleomorphism in cell microanatomy at an ultrastructural level. We have obtained different sublines of 8701-BC cells by cloning in soft agar at different concentrations (0.3% and 0.6%), and we have characterized the cloned lines by some morphological and growth parameters. 8701-BC cells and clones have been submitted to analysis by reverse transcriptase-linked polymerase chain reaction to detect mRNAs of various cytokines (transforming growth factor-beta s, tumour necrosis factors, interleukin 1s, interleukin 6, parathyroid hormone-related peptide, gamma in…
Cellular mechanism of action of thyroid hormones.
1987
Abstract It has emerged in the last decade that the molecular mechanism of action of thyroid hormones resembles that of steroids; thyroid hormones indeed exert their effects mainly by directly regulating gene expression, on association with specific chromatin-bound receptors. Of the two thyroid hormones, thyroxine (T4) appears to be a sort of prohormone, whereas triiodothyronine (T3) seems to be the active form; in this respect, T4-deiodination, which occurs at the level of the target tissues, may be crucial in the local homeostasis of T3. Moreover, many cellular compartments, other than the nucleus, can bind thyroid hormone, and at least some of these further sites might play some role in …
Nuclear receptors modulate the interaction of Sp1 and GC-rich DNA via ternary complex formation
2000
Binding sites for transcription factor Sp1have been implicated in the transcriptional regulation of several genes by hormones or vitamins, and here we show that a GC-rich element contributes to the retinoic acid response of the interleukin 1β promoter. To explain such observations, it has been proposed that nuclear receptors can interact with Sp1 bound to GC-rich DNA. However, evidence supporting this model has remained indirect. So far, nuclear receptors have not been detected in a complex with Sp1 and GC-rich DNA, and the expected ternary complexes in non-denaturing gels were not seen. In search for these missing links we found that nuclear receptors [retinoic acid receptor (RAR), thyroid…
Improved yield and functionality of parathyroid cells separated by using collagenase-digestion with cold pre-incubation.
2001
Preparation of cells from solid organs often induces a functional impairment due to the proteolytic cell damage by the applied digestive enzyme like collagenase, trypsin or dispase. To preserve the tissue and to enhance the yield of cells, Laue et al. reported an islet cell isolation with pre-incubation at 4 C permitting the enzyme to diffuse into the tissue and explicite activity equally throughout the whole particle. The aim of this study was to investigate whether this procedure can be applied to parathyroid glands. Therefore porcine parathyroid glands were dissected into 1 mm3 pieces. Subsequently one group of these pieces was incubated 22 h at 4 C in 2 mg/ml collagenase before activati…
PTHrP [67-86] regulates the expression of stress proteins in breast cancer cells inducing modifications in urokinase-plasminogen activator and MMP-1 …
2003
It was previously reported that a midregion domain of parathyroid hormone-related protein (PTHrP), that is, [67-86]-amide, is able to restrain growth and promote matrigel penetration by the 8701-BC cell line, derived from a biopsy fragment of a primary ductal infiltrating carcinoma of the human breast, and that cell invasion in vitro is drastically impaired by inactivation of urokinase-plasminogen activator (uPa). In this study we started a more detailed investigation of the possible effects on gene expression arising from the interaction between PTHrP [67-86]-amide and 8701-BC breast cancer cells by a combination of conventional-, differential display-and semi-quantitative multiplex-polyme…