Search results for " antagonist"
showing 10 items of 1421 documents
Lack of binding of gestodene to estrogen receptor in human breast cancer tissue
1990
Competition studies with progesterone and estradiol receptors of human myometrial tissue as well as of mammary cancer tissue showed that gestodene bound with high affinity to the progesterone receptor, as did other synthetic and natural progestogens. However, gestodene did not bind to the estradiol receptor. The relative binding affinities of all tested synthetic and natural ligands showed no organ-specific differences and no differences between neoplastically transformed and normal tissues.
Current perspectives on parathyroid hormone (PTH) and PTH-related protein (PTHrP) as bone anabolic therapies.
2013
Osteoporosis is characterized by low bone mineral density and/or poor bone microarchitecture leading to an increased risk of fractures. The skeletal alterations in osteoporosis are a consequence of a relative deficit of bone formation compared to bone resorption. Osteoporosis therapies have mostly relied on antiresorptive drugs. An alternative therapeutic approach for osteoporosis is currently available, based on the intermittent administration of parathyroid hormone (PTH). Bone anabolism caused by PTH therapy is mainly accounted for by the ability of PTH to increase osteoblastogenesis and osteoblast survival. PTH and PTH-related protein (PTHrP)-an abundant local factor in bone- interact wi…
Non-functioning parathyroid cystic tumour: malignant or not? Report of a case
2017
Parathyroid carcinoma (PC) is a very rare endocrine tumour, usually characterized by symptoms such as a neck mass, dysphonia, severe hypercalcemia exceeding 140 mg/L and elevated serum parathyroid hormone levels, even more than 5 times the upper limit of normal. Non-functioning parathyroid cancer is extremely rare and, in this case, its pre-operative diagnosis is often difficult. A 54-year old female patient, referring dysphagia and dysphonia, underwent neck ultrasound and neck CT. A left thyroid nodule, probably cystic, was found. It presented caudal extent on anterior mediastinum causing compression of the left lateral wall of the trachea. The preoperative calcemia was into the normal ran…
Birth Weight and Diabetic Retinopathy: Results From the Population-Based Gutenberg Health Study (GHS).
2020
Purpose: This study investigates the relationship between diabetic retinopathy (DR) and birth weight (BW) in diabetic subjects sampled from the general population. Methods: The Gutenberg Health Study (GHS) is a population-based, observational cohort study in participants aged from 35 to 74 years. Criteria for diabetes diagnosis were HbA1c ≥6.5% at study entry, a doctor-diagnosis of diabetes, or diabetes medication. The presence of DR was determined by evaluating fundus photographs. BW was assessed by self-reports. GHS participants were divided into three different BW groups (low: <2500 g; normal: 2500–4000 g; high:>4000 g). Logistic regression analysis was conducted as uni- and multiv…
Antipsychotic drugs antagonize human serotonin type 3 receptor currents in a noncompetitive manner
2004
The serotonin type 3 (5-HT(3)) receptor is the only ligand-gated ion channel receptor for serotonin (5-HT). 5-HT(3) receptors play an important role in modulating the inhibitory action of dopamine in mesocorticolimbic brain regions. Neuroleptic drugs are commonly thought to exert their psychopharmacological action mainly through dopamine and serotonin type 2 (5-HT(2)) receptors. Except for clozapine, a direct pharmacological interaction of neuroleptics with 5-HT(3) receptors has not yet been described. Using the concentration-clamp technique, we investigated the effects of flupentixol, various phenothiazines, haloperidol, clozapine and risperidone on Na(+)-inward currents through 5-HT(3) re…
Effects of dopamine in isolated rat colon strips.
2005
The aim of the present work is to investigate the effects of dopamine on isolated rat colon strips, and whether dopamine receptors are involved in these effects. Experiments on spontaneous motility and under potassium contraction were performed with dopamine and isoprenaline, both in the absence and presence of antagonists (distal colon strips, isotonic recording, Tyrode solution, 31 °C, 1 g of resting tension). At higher concentration (10–4mol/L), dopamine abolished spontaneous motility of the rat colon and this effect was not modified by antagonists. In isolated rat colon strips that were depolarized with potassium, dopamine produced concentration-dependent relaxation, without significant…
Substance P inactivation by transglutaminase in vitro.
1992
Gamma(glutamyl5)spermine derivative of substance P (Spm-SP) was synthesized in vitro in the presence of purified guinea pig liver transglutaminase and Ca2+. The spermine adduct of the neuropeptide was purified by HPLC on a reversed-phase column and characterized by fast atom bombardment mass spectrometry. The biological activities of Spm-SP were tested by assaying, in comparison with substance P, its ability to induce both the contractions of smooth muscle in vitro and the edema formation in vivo. Spm-SP was shown not to elicit contractile responses in the isolated rat stomach strip and duodenum and not to antagonize the spasmogenic effect evoked by the native neuropeptide. Furthermore, Spm…
Release of acetylcholine from murine embryonic stem cells: Effect of nicotinic and muscarinic receptors and blockade of organic cation transporter
2012
The non-neuronal cholinergic system is widely expressed in nature. The present experiments were performed to characterize the non-neuronal cholinergic system in murine embryonic stem cells (CGR8 cell line).CGR8 cells were cultured in gelatinized flasks with Glasgow's buffered minimal essential medium (Gibco, Germany). Acetylcholine was measured by HPLC combined with bioreactor and electrochemical detection.CGR8 cells contained 1.08±0.12 pmol acetylcholine/10(6) cells (n=7) which was reduced to 0.50±0.06 pmol/10(6) cells (n=6; p0.05) in the presence (4h) of 30μM bromoacetylcholine to block choline acetyltransferase. A time-dependent release of acetylcholine into the incubation medium was dem…
Isoprenaline and forskolin increase evoked vasopressin release from rat pituitary
1982
Isolated neurointermediate lobes of rat pituitaries were incubated in Krebs solution. The vasopressin release evoked by electrical stimulation (0.2 ms, 80 V, 15 Hz, 10 s trains at 10 s intervals for a total of 10 min) was completely inhibited by tetrodotoxin. Isoprenaline increased the evoked vasopressin release to a maximum of 60% (EC50 10 nM) and this effect was antagonized surmountably by propranolol. Forskolin increased the vasopressin release by 98%. These results suggest the presence within the neurohypophysis of a beta-adrenoceptor-linked adenylate cyclase facilitating vasopressin secretion.
Agouti-related peptide-expressing neurons are mandatory for feeding.
2005
Multiple hormones controlling energy homeostasis regulate the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus. Nevertheless, inactivation of the genes encoding NPY and/or AgRP has no impact on food intake in mice. Here we demonstrate that induced selective ablation of AgRP-expressing neurons in adult mice results in acute reduction of feeding, demonstrating direct evidence for a critical role of these neurons in the regulation of energy homeostasis.