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

The stress response in humans commonly includes elevations in plasma concentrations of glucocorticoids, catecholamines, glucagon, growth hormone, aldosterone, and renin, resulting in alterations in the metabolism of glucose and other energy substrates, and in increased sodium and water retention. In severe illness, triiodothyronine and sometimes thyroxine are decreased without evidence of clinical hypothyroidism. Antidiuretic hormone may be elevated in bacterial meningitis and other central nervous system disorders, as well as in acute asthma, chronic ventilator therapy, pneumothorax, atelectasis, and postoperatively. Increased ADH concentration can lead to significant hypoosmolality and hyponatremia with adverse effects on the patient. In the setting of severe intracerebral insults, ADH may be inappropriately low, resulting in diabetes insipidus. Insulin concentrations may be inappropriately low for serum glucose concentration, or insulin may have diminished receptor responsiveness in seriously stressed patients. Either situation leads to hyperglycemia. Disturbances in calcium, phosphorus, and magnesium homeostasis may occur relatively frequently in the critically ill patient in response to therapeutic interventions, or illness-induced altered metabolism. It is not always clear when an altered metabolic or hormonal state is an appropriate response to a stress, or represents decompensation of the body's mechanisms for coping with that stress. It is important, however to recognize the common responses of the organism to severe illness, and to monitor for treatable abnormalities which occur.
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PMID:Endocrine manifestations of critical illness in the child. 354 20

Hormonal control of glucose production and of L-pyruvate kinase activity has been measured in isolated liver cells from fed control and thyroidectomized rats. In hypothyroid rats, sensitivity to isoproterenol as measured by these parameters was increased: the apparent K0.5 for isoproterenol-induced stimulation of glucose production decreased from 8.0 +/- 3 X 10(-6) M in control rats to 2.0 +/- 0.2 X 10(-8) M in hypothyroid rats (P less than 0.001) and the apparent K0.5 for inhibition of L-pyruvate kinase was 5 +/- 2 X 10(-7) M vs. 7 +/- 2 X 10(-9) M (P less than 0.001) in control and thyroidectomized rats, respectively. Utilisation of specific adrenergic antagonists confirmed increased beta-adrenergic responsiveness in hypothyroid rats. This phenomenon was not reversed by 3 days of T3 treatment (10 micrograms/100 g body weight). Sensitivity to the alpha-agonist was unchanged by thyroid status. Stimulation of glucose production and inhibition of L-pyruvate kinase activity by glucagon and their reversal by insulin were not affected by hypothyroidism. The dose-response curve to vasopressin and its maximal effect measured on stimulation of glucose production were unchanged in thyroidectomized rats. Thus, hypothyroidism produces a specific enhancement of liver beta-adrenergic responsiveness without affecting sensitivity to glucagon, insulin and vasopressin.
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PMID:Hormonal control of glucose production and pyruvate kinase activity in isolated rat liver cells: influence of hypothyroidism. 356 54

Thyrotropin-releasing hormone (TRH) is present in small quantities in the rat adult pancreas. As hypothyroidism increases dramatically the pancreatic content of this peptide, this model was used to localize TRH in the gland by immunocytochemistry. Immunocytochemical staining of semithin (0.5-1.0 micron) and thin (golden) sections was performed as well as antibody and method controls to check the specificity of the immunoperoxidase staining. At the light microscope level, a very faint TRH-like immunoreactivity was apparent in the pancreas of normal untreated animals. In hypothyroid rats, a strong TRH immunostaining was observed in the central portion of the islets of Langerhans. On the contrary, in previously hypothyroid rats made euthyroid, no TRH-like immunoreactivity was found. Serial sections alternately labelled with TRH and insulin antisera revealed the simultaneous occurrence of both immunoreactivities. In addition, the TRH immunoreactive cells were distinct from glucagon- or somatostatin-containing cells. At the electron microscope level, immunoreactive TRH was found over the secretory granules of insulin-containing cells. Hypothyroid animals offer therefore a suitable model for the study of TRH in the pancreas.
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PMID:Immunocytochemical location of thyrotropin-releasing hormone (TRH) in the B-cells of adult hypothyroid rat pancreas. 392 74

We have assessed the presence of VIP/PHI/secretin receptors in heart by: (1) testing the ability of the corresponding peptides to activate adenylate cyclase in cardiac membranes from rat, dog, Cynomolgus monkey and man, and (2) examining the ability of the same peptides to exert inotropic and chronotropic effects on heart preparations from rat and Cynomolgus monkey in vitro. Based on their affinity for natural peptides and synthetic analogs, two types of VIP/PHI/secretin receptors were characterized: the relatively nonspecific "secretin/VIP receptor" of rat heart (that is "secretin-preferring" only in that secretin was more efficient than VIP in stimulating adenylate cyclase), and the "VIP/PHI-preferring" receptor of man, monkey and dog heart. Four physiopathological situations affecting secretin/VIP receptors in rat heart were explored: In male rats from the Okamoto strain and the Lyon strain, two strains presenting spontaneous hypertension, heart membranes exhibited a markedly decreased response of adenylate cyclase to secretin/VIP, with lesser alterations in the responses to isoproterenol and glucagon. This impairment developed in parallel with the occurrence of hypertension and was reproduced in normotensive rats submitted to chronic isoproterenol treatment (but not in Goldblatt hypertensive rats). These findings are consistent with a hyperactivity of norepinephrine pathways in spontaneously hypertensive rats, leading to a reduced number of cardiac post-junctional secretin/VIP receptors bound to adenylate cyclase. Heart membranes from genetically obese (fa/fa) Zucker rats also exhibited severely decreased responses to secretin/VIP with lesser alterations in the responses to glucagon and isoproterenol. These anomalies were specific for the heart, and developed in concomitance with obesity. The first anomaly could not be corrected by severe food restriction. Secretin stimulation of heart adenylate cyclase was also selectively altered in streptozotocin-diabetic rats. Thus, two types of diabetic cardiomyopathy were characterized by a severe local alteration of secretin/VIP receptors coupled to adenylate cyclase. Hypothyroidism, provoked in rat by thyroidectomy or propylthiouracil treatment, again induced a marked decrease in secretin-stimulated cardiac adenylate cyclase activity. In rat papillary muscle electrically stimulated in vitro, secretin exerted a positive inotropic effect. This effect was reduced in obese (fa/fa) Zucker rats. In rat right atrium, secretin also exerted a positive chronotropic effects.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Heart receptors for VIP, PHI and secretin are able to activate adenylate cyclase and to mediate inotropic and chronotropic effects. Species variations and physiopathology. 608 34

The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treatment on body temperature and serum and tissue levels of thyroid hormones, glucose, glucagon, insulin, and somatostatin were investigated. Within 7 days following TCDD administration (45 micrograms/kg), rats exhibited hypothyroidism compared to pair-fed controls and rats fed ad libitum. Body temperature was maintained in the pair-fed and ad libitum-fed controls but was significantly decreased in TCDD-treated rats at 2 days. Within 2 weeks of the administration of 90 micrograms TCDD/kg, body temperature was below 35 degrees C with the lowest mean value of 34.5 degrees C recorded on Day 16. Mean body temperatures for control rats ranged from 36.8 to 37.5 degrees C. One week after TCDD administration (45 micrograms/kg), serum thyroxine (T4) declined to 46% of pair-fed controls. The decreased free-thyroxine index indicated that the measured decrease in thyroxine reflected decreased hormone concentrations as opposed to altered protein binding. Hypoglycemia occurred in TCDD-treated rats subsequent to hypothyroxinemia and hypothermia, but it did not develop in the pair-fed controls. At 1 week after administration of 45 micrograms TCDD/kg, serum and pancreatic insulin levels were reduced to 25 and 76% of ad libitum-fed controls, respectively. Hypophagia was determined to be responsible for the decreased growth rate and hypoinsulinemia but did not account for hypothyroxinemia, hypothermia, and hypoglycemia following the administration of TCDD. No significant alterations were detected in serum glucagon or in pancreatic, hepatic, or serum somatostatin levels. Decreased somatostatin in the gastric antrum coincided with a 29% increase in stomach dry weight. The delayed toxicity of TCDD may result, in part, from these hormonal alterations.
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PMID:Hypothyroxinemia and hypothermia in rats in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin administration. 613 53

The role of endogenous glucagon and insulin on the hepatic glycogen and triglyceride storage syndrome in propylthiouracil (PTU)-induced hypothyroidism was investigated in the chick. PTU feeding in the diet resulted in a progressive increase in liver glycogen concentration associated with a concomitant decrease in hepatic glucose-6-phosphatase (G-6-Pase) activity. Plasma glucagon level was significantly decreased and insulin significantly increased after two days of PTU administration. These enzyme and hormone changes were associated with a significant increase in hepatic glucose-6-phosphate (G-6-P) and a decrease in cyclic AMP levels. Although our results do not directly prove, the data does suggest that the hepatic glycogen storage syndrome observed in the PTU-induced hypothyroidism in the chick is mediated through changes in pancreatic glucagon and insulin secretion. The extent of glycogen accumulation was inversely related to G-6-Pase which is a rate limiting glycogenolytic enzyme. A significant increase in the plasma insulin/glucagon ratio, along with a significant decrease in the hepatic cyclic AMP concentration, could most likely also account for the excessive hepatic triglyceride accumulation in the PTU-treated chicks.
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PMID:Elevated insulin/glucagon ratios and decreased cyclic AMP levels accompany the glycogen and triglyceride storage syndrome in the hypothyroid chick. 624 95

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).
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PMID:[The effect of thyroid function on the increase of plasma cyclic AMP following glucagon injection (author's transl)]. 625 72

The binding capacity and relative affinities of the nuclear triiodothyronine receptors were measured in the cerebral cortex and liver tissues of the rat under several conditions involving energy deprivation. Protracted hypothyroidism caused significant increases in binding capacity in both brain and liver representing a probable direct tissue response to this specific thyroidal dysfunction. Three conditions affecting glucose homeostasis: fasting, glucagon administration and insulin-induced acute hypoglycemia, caused a significant decrease in nuclear binding capacity measured by in vitro binding assay in liver but did not affect brain receptors indicating a tissue specific response to these altered energy states. Lowering of available oxygen (hypoxia) also appeared to cause a slight decrease in binding capacity in the cerebral cortex measured in vitro. On the other hand, total depletion of oxygen (anoxia) showed a progressive increase in binding of a lower affinity nature in the cerebral cortex and liver. A similar change in binding and affinity was seen in the progression of the post-mortem condition in the cerebral cortex and liver resulting from a probable general alteration of the chromosomal material. These results illustrate the degree and nature of alterations of a specific nuclear regulatory component, the thyroid hormone receptor, under several pathological conditions.
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PMID:Effects of various pathological conditions on the nuclear T3 receptors of rat cerebral cortex: comparison with liver. 631 68

The actions of hormones which are associated to cAMP-dependent and calcium-dependent mechanisms of signal transduction were studied in hepatocytes obtained from rats with different thyroid states. In cells from euthyroid and hyperthyroid rats, the metabolic actions of epinephrine were mediated mainly through alpha 1-adrenoceptors; beta-adrenoceptors seem to be functionally unimportant. In contrast, both alpha 1- and beta-adrenoceptors mediate the actions of epinephrine in hepatocytes from hypothyroid animals. Phosphatidylinositol labeling was strongly stimulated by epinephrine, vasopressin and angiotensin II in cells from eu-, hyper- or hypothyroid rats. However, metabolic responsiveness to vasopressin and angiotensin II was markedly impaired in the hypothyroid state. The glycogenolytic response to the calcium ionophore A-23187 was also impaired, suggesting that hepatocytes from hypothyroid rats are less sensitive to calcium signalling. The persistence of alpha 1-adrenergic responsiveness in the hypothyroid state suggests that the mechanism of signal transduction for alpha 1-adrenergic amines is not identical to that of the vasopressor peptides. alpha 1-Adrenergic stimulation of cyclic AMP accumulation was not detected in cells from hypothyroid rats. These data suggest that factors besides calcium and besides cAMP are probably involved in alpha 1-adrenergic actions. Metabolic responses to glucagon and to the cAMP analogue dibutyryl cAMP were not markedly changed during hypothyroidism, although cAMP accumulation produced by glucagon and beta-adrenergic agonists was enhanced. In hyperthyroidism, cell responsiveness to epinephrine, vasopressin, angiotensin II and glucagon was decreased, but sensitivity to cAMP was not markedly altered. The factors involved in this hyposensitivity to hormones during hyperthyroidism are unclear.
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PMID:Modulation by thyroid status of cyclic AMP-dependent and Ca2+-dependent mechanisms of hormone action in rat liver cells. Possible involvement of two different transduction mechanisms in alpha 1-adrenergic action. 632 Sep 11

Inhibition of adenylate cyclase has been proposed as a mechanism for hypothyroidism and nephrogenic diabetes insipidus occurring during lithium treatment, but these disorders are rarely found in the same patients. We have measured plasma levels of adenosine 3':5'-cyclic monophosphate (cyclic AMP) after an intravenous injection of glucagon in eight patients receiving long term lithium treatment and in six control subjects. Urinary cyclic AMP levels after an intravenous injection of bovine parathyroid hormone (PTH) were also measured in the patients. The plasma cyclic AMP response to glucagon in the patient group was significantly lower than that of the controls. No correlation was demonstrated between the plasma cyclic AMP response after glucagon and the urinary cyclic AMP response after PTH. We have previously shown that impairment of the response to PTH correlates with reduced urine concentrating ability during lithium treatment. In contrast, there was no correlation between the responses to PTH and glucagon in individual patients. These results are consistent with the hypothesis that inhibition of adenylate cyclase is an important factor in lithium-induced endocrine dysfunction.
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PMID:Cyclic AMP responses to parathyroid hormone and glucagon during lithium treatment. 632 91


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