Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The results of testing growth hormone (GH) reserve using human pancreatic growth hormone-releasing factor 1-44 amide (hp GRF 1-44 amide) have been compared with the GH responses in a variety of other dynamic tests in seven acromegalic patients. The GH release following hp GRF 1-44 amide correlated with the GH suppression following bromocriptine, but showed an inverse correlation with the GH release following stress tests (insulin-induced hypoglycaemia/glucagon). There was no correlation between the GH responses in these three tests and any of the other tests: TRH, GnRH and glucose. A hypothesis is proposed to explain these findings on the basis of varying degrees of GH secretion from adenomatous and normal pituitary somatotrophs in acromegaly.
 ...
PMID:Growth hormone responses to hp GRF 1-44 amide, bromocriptine and stress in acromegaly are correlated. 312 Jan 67

Systemic absorption of polypeptides through eyes has been demonstrated in this study to provide an effective route of peptide administration as an alternate to parenteral administration. TRH at 0.0025% reached a plateau of blood concentration at 0.05 ng/ml in 60 min. and stayed high for at least 4 hrs, thereafter. In contrast, a therapeutic dose of TRH (15 micrograms/70 kg i.v.) could maintain a blood concentration of 0.07 ng/ml. At 1%, TRH reached a plateau of 26 ng/ml in 2 hrs. and persisted in the plateau for 10 hrs. thereafter. At 5%, TRH peaked at 138 ng/ml in 60 min. and then fell gradually to a steady state of 60 ng/ml in 9 hrs from the peak. Addition of peptidase inhibitors (Leu-Leu, 4 mM; Bestatin, 60 microM; and DL-Thiorphan 0.6 microM) did not affect the uptake of TRH into systemic circulation. LHRH showed entirely different kinetic of systemic absorption through eyes. The blood concentration never reached peak or plateau during 12 hrs. of experimental period. The blood concentration of LHRH increased steadily during experiments. With 0.0025%, 1% and 5% of LHRH, they reached final highest blood concentrations of 0.13 ng/ml, 45 ng/ml and 95 ng/ml, respectively. The therapeutic dose of LHRH (15 micrograms/70 kg i.v.) could maintain a blood concentration at 0.25-0.3 ng/ml which was slightly higher than that reached with 0.0025% of LHRH instilled into the eye. Addition of peptidase inhibitor (Leu-Leu, 5 mM) enhanced the absorption of LHRH into systemic circulation slightly but significantly. Glucagon behaved similarly as TRH except that the blood concentration remained high without falling at 5% dose level. These results suggest that topical instillation of peptide drugs into eyes is a workable method for administration of these peptide drugs.
 ...
PMID:Systemic delivery of polypeptides with molecular weights of between 300 and 3500 through the eyes. 317 41

A non-neoplastic syndrome of inappropriate secretion of TSH (ITSHS) was diagnosed in a hemithyroidectomized and clinically euthyroid 44-yr-old man, who also exhibited limping (Perthes' disease), genu valgum, pes supinatus and lateral nystagmus. Computed tomography demonstrated an enlarged sella turcica due to empty sella. Baseline serum T3, T4, free T3, free T4 and TSH fluctuated between 179 and 274 ng/dl, 6.0 and 13.2 micrograms/dl, 4.2 and 6.0 pg/ml, 7.6 and 15.3 pg/ml, and 4.3 and 33.0 microU/ml, respectively. Serum alpha-TSH subunit was repeatedly normal (0.36-0.69 ng/ml) over the follow-up period (greater than 3 yr). No changes in serum liver enzymes and lipids were observed after thyroid hormone administration, whereas red blood cell glucose-6-phosphate dehydrogenase (G-6-PD) and urinary OH-proline were slightly enhanced during 120 micrograms/day L-T3 regimen. This also resulted in an inappropriately normal glucagon-stimulated cAMP levels. Tachycardia was experienced only during L-T3 and very high L-T4 dose treatments. Therefore, the patient showed some evidence for thyroid hormone peripheral refractoriness. Patient's TSH was physiologically responsive to agents (thyrotropin releasing hormone, methimazole, the dopamine antagonists domperidone and sulpiride) known to elicit its release into circulation, while it responded paradoxically to those which normally inhibit TSH secretion. In fact, the infusion of somatostatin (320 micrograms/h) or dopamine (4 micrograms/Kg/min), and the oral administration of bromocriptine or nomifensine (two dopamine agonists) or corticosteroids (dexamethasone) provoked an unexpected elevation of both unstimulated and TRH-stimulated TSH levels.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Abnormal daily periodicity of serum thyrotropin (TSH) and evidence for defective TSH suppression in a case of non-neoplastic syndrome of inappropriate TSH secretion. 358 59

Thyrotropin-releasing hormone, TRH, increases the plasma levels of glucagon, insulin, glucose and free fatty acids in rabbits. However, TRH has no direct effects on the release of hormones neither from the endocrine pancreas in humans nor from the isolated perfused rat pancreas. The aim of the present study was to investigate if the effects of TRH in rabbits were mediated by the autonomic nervous system. The TRH "Roche"-induced hyperglucagonemia was inhibited by phentolamine (an alpha-receptor blocking drug), yohimbine (an alpha-2 -receptor blocking drug) and atropine. The TRH "Roche"-induced hyperinsulinemia was inhibited by propranolol (a beta-receptor blocking drug). The TRH "Roche"-induced hyperglycemia was inhibited by all four drugs. The TRH "Roche"-induced increases in the plasma levels of free fatty acids were not inhibited by the sympathetic and parasympathetic blocking drugs. The effects of TRH "Roche" on the plasma levels of glucagon, insulin and glucose cannot be explained by increases in the plasma levels of catecholamines. TRH, given intravenously into rabbits, may possibly act on regions in the central nervous system which control carbohydrate metabolism and the release of glucagon and insulin from the endocrine pancreas by sympathetic and parasympathetic mechanisms.
 ...
PMID:Involvement of the autonomic nervous system in the in vivo TRH-induced increases in the plasma levels of glucagon, insulin and glucose in rabbits. 392 49

A study was made of the TRH effect on insulin and glucagon secretory function of a 4-day neonatal rat pancreatic islet cell culture. The TRH effect was determined in the range of 10-1000 ng/ml concentrations within 30 min and 3 h of cell cultivation with the hormone. TRH stimulated insulin and glucagon secretion within the range of the above doses. No dose dependence was revealed in the TRH stimulation of insulin and glucagon secretion. The data obtained suggest that TRH produces an direct effect on islet cell function stimulating insulin and glucagon secretion.
 ...
PMID:[Effect of thyroliberin on pancreatic islet cell function in rats]. 392 57

An assay for the binding of [(3)H]thyrotropin-releasing hormone ([(3)H]TRH) is described. Plasma membranes isolated from bovine anterior pituitary gland bind about 600 femtomoles of this hormone per mg of protein, as compared to 15 femtomoles per mg of protein in the total adenohypophyseal homogenate (40-fold purification). The equilibrium constant of membrane receptor-[(3)H]TRH binding at 0 degrees C is 4.3 x 10(7) L.M(-1), or a half-maximal binding of this hormone at 23 nM. The binding is time-dependent; addition of unlabeled hormone induces dissociation of the receptor-[(3)H]TRH complex with a half-life of 14 min. The binding of TRH is not altered by 10 muM melanocyte-stimulating hormone-release inhibiting hormone, lysine-vasopressin, adrenocorticotropin, growth hormone, prolactin, luteinizing hormone, insulin, glucagon, L-thyroxine, or L-triiodothyronine. K(+) and Mg(++) increase formation of the receptor-TRH complex at optimal concentrations of 5-25 mM and 0.5-2.5 mM, respectively, with inhibition at higher concentrations. Ca(++) inhibits binding of TRH at all concentrations tested.
 ...
PMID:Binding of thyrotropin-releasing hormone to plasma membranes of bovine anterior pituitary gland (hormone receptor-adenylate cyclase-equilibrium constant-( 3 H)thyrotropin). 462 48

The effect of VIP on prolactin secretion from incubated rat hemipituitaries was characterized. Under these conditions, the secretion of GH, LH, FSH, ACTH was not affected, indicating that the effect of VIP is hormone specific. The stimulation of prolactin was dose-dependent, with an apparent affinity of VIP of 10.9 +/- 3.1 nM and a maximal stimulation of 57.7 +/- 4.2%. Secretin, a structurally related peptide, was also active at higher concentrations, whereas another partial analogue, glucagon, was ineffective. Furthermore, VIP does not act through pituitary DA receptors since alpha-flupentixol, a potent dopaminergic antagonist, does not block the stimulation of prolactin secretion by VIP. In addition, stimulation by VIP and TRH was additive. Naloxone and met-enkephalin were ineffective on the VIP effect on prolactin release. In contrast, SRIF seems to inhibit the VIP stimulation of prolactin release. Our data suggest that VIP, which was found in the hypothalamo-hypophyseal blood at concentrations of the same order of magnitude as that found to stimulate PRL in vitro, could be a physiological PRF.
 ...
PMID:[PRF activity of VIP in vitro (author's transl)]. 612 34

The present study was undertaken to determine the plasma levels of somatostatin-like immunoreactivity (SLI) during constant infusion of graded concentrations of synthetic somatostatin-14 (S-14); to determine the half-life (t1/2) and metabolic clearance rate (MCR) of SLI; to correlate the plasma SLI levels with the degree of inhibition of pituitary and islet hormone secretion and to establish whether the plasma SLI levels capable of inhibiting pituitary and islet hormone secretion fall into the physiological range. Four normal subjects on separate occasions were each infused with saline or S-14 (25,50 and 75 micrograms/h) at a constant rate for 2 1/2 h. Thirty min following the infusions, TRH (200 micrograms) and arginine (0.5 g/kg) were given i.v. Blood samples were drawn every 15 min for measurement of GH, TSH, insulin, glucagon and SLI (by RIA of acid-ethanol extracted plasma) and at rapid intervals for 10 min after stopping the infusions for measurement of SLI disappearance. During S-14 infusions, plasma SLI rose rapidly, reached a plateau from 15-150 min and declined rapidly on cessation of the infusions with a mean t 1/2 of 2.72 +/- 0.45 min. Mean plateau SLI levels were: 149 +/- 3 pg/ml (25 micrograms/h), 465 +/- 35 pg/ml (50 micrograms/h), and 1244 +/- 71 pg/ml (75 micrograms/h). SLI was cleared rapidly but the MCR exhibited a dose-dependent decrease from 3225 +/- 699 ml/min for the 25 micrograms infusion to 1249 +/- 241 ml/min for the 75 micrograms/h infusion (P less than 0.05). The 25 micrograms/h infusion dose produced near-maximal suppression of GH secretion and inhibited insulin secretion but not TSH or glucagon secretion. The intermediate dose significantly inhibited GH, TSH, and insulin but not glucagon whereas the 75 micrograms/h infusion suppressed all four hormones. In six normal subjects endogenous plasma SLI rose from a basal value of 32.5 +/- 4.9 pg/ml to 75.5 +/- 9.0 pg/ml following ingestion of a mixed meal. This level was 50% of that resulting from the 25 micrograms/h infusion and which suppressed GH almost completely. We concluded that: Infused S-14 is cleared rapidly and decays with a short t 1/2; S-14 inhibits its own MCR; The somatotrophs are the most sensitive to S-14 inhibition, followed by the thyrotrophs and the B-cells (approximately equally) followed by the A-cells; Fluctuations in plasma SLI occurring physiologically may influence GH and possibly other S-14 sensitive cells by an endocrine mechanism.
 ...
PMID:Infusion of graded concentrations of somatostatin in man: pharmacokinetics and differential inhibitory effects on pituitary and islet hormones. 614 13

Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel chromatography and exhibited dilution curves parallel with synthetic TRH in radioimmunoassay. [3H]Histidine was incorporated into a component that reacted with TRH antiserum and had the same retention time as synthetic TRH on reversed-phase high-performance liquid chromatography. A continuous release of TRH-IR into the culture medium was observed from islets of both 5-d-old (newborn) and 30-d-old (adult) rats with a maximum on the second day of culture (28.7 +/- 7.0 and 13.3 +/- 3.6 fmol/islet per d, respectively). The content of TRH-IR was higher in freshly isolated islets from newborn rats (22.4 +/- 2.3 fmol/islet) than in adult rat islets, which, however, increased their content from 1.3 +/- 0.5 to 7.0 +/- 0.5 fmol/islet during the first 3 d of culture. Adult rat islets maintained in medium with 20 mM glucose released significantly more TRH-IR than islets in 3.3 mM glucose medium (13.0 +/- 0.7 vs. 4.3 +/- 0.3 fmol/islet per d). In contrast, the content of TRH-IR in the islets was reversed (1.4 +/- 0.3 vs. 4.7 +/- 1.6 fmol/islet). By exposing islets from newborn rats to streptozotocin 0.7 mg/ml for 30 min, a 50% reduction of TRH-IR content in the islets compared with the non-treated islets was seen after subsequent culture for 7 d. The insulin content was reduced by 80%, while glucagon was slightly elevated. In conclusion, these results indicate that TRH is synthesized in rat pancreatic islets, and that the release is stimulated by glucose.
 ...
PMID:Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin. 622 32

The increase in plasma cyclic adenosine-3':5'-monophosphate (cAMP) was measured after intravenous injection of 1 mg of glucagon in 26 normal subjects, 36 patients with hyperthyroidism, 35 patients with hypothyroidism and 24 patients with euthyroid goitre. While patients with euthyroid goitre responded normally, the plasma cyclic AMP response in patients with hyperthyroidism was considerably increased and in those with hypothyroidism decreased. 4 patients with cirrhosis of the liver had reduced responses and 1 patient with extrahepatic obstructive jaundice an enhanced response. This test seems to be a valuable additional parameter for the description of the thyroid-dependent metabolic situation. However, because of its unspecificity it cannot replace the measurement of serum T3, T4 and thyrotropin (TSH) response to thyroliberin (TRH).
 ...
PMID:[The effect of thyroid function on the increase of plasma cyclic AMP following glucagon injection (author's transl)]. 625 72


<< Previous 1 2 3 4 5 6 Next >>