Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.16.2 (tyrosine hydroxylase)
 14,760 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tyrosine-3-monooxygenase activity [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] of rat adrenal medulla is induced 20-24 hr after the injection of reserpine (16 mumol/kg intraperitoneally). This and other inducing stimuli increase the 3': 5'-cyclic AMP (cAMP) content in the medulla for longer than 60 min and activate the cAMP-dependent protein kinase (ATP: protein phosphotransferase; EC 2.7.1.37) for several hours. Corticotropin (ACTH), dopamine, and propranolol do not induce the monooxygenase, but elicit an increase in the cAMP content of the medulla which fails to activate protein kinase and lasts less than 1 hr. A high- and low-molecular-weight protein kinase are separated by gel filtration from the 20,000 X g pellet extract of adrenal medulla homogenate. The activity of the low-molecular-weight enzyme is expressed as its ability to phosphorylate histone. The protein kinase activity of the pellet is increased between 3 and 17 hr after reserpine injection. Our evidence indicates that this increase is due to a translocation from cytosol to subcellular structures of a kinase that utilizes lysine-rich histone as phosphate acceptor. The protein kinase activity that is extracted from a purified nuclear fraction prepared from the adrenal medulla of rats injected 7 hr previously with reserpine is greater than that extracted from medulla of saline-treated rats.
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PMID:Activation and nuclear translocation of protein kinase during transsynaptic induction of tyrosine 3-monooxygenase. 0 93

Pretreatment of rats with dexamethasone (2.5 mumol/kg, a dose which blocks the release of ACTH from the pituitary gland) abolished the reserpine mediated increase in cAMP and the increase in the cAMP/cGMP ratio in the adrenal medulla. In contrast, the reserpine-mediated induction of tyrosine hydroxylase (TH) remained unchanged. Hypophysectomy had a similar effect to dexamethasone treatment. Since changes in cAMP and changes in the cAMP/cGMP ratio are not indispensible prerequisities for the subsequent induction of TH, a causal relationship between the two phenomena seems to be excluded.
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PMID:Lack of correlation between changes in cyclic nucleotides and subsequent induction of tyrosine hydroxylase in rat adrenal medulla. 0 54

When dexamethasone 0.25 or 2.5 mumole/kg i.p. was injected 2 h before reserpine (16 mumol/kg i.p.) the time course of the increase in cAMP content of rat adrenal medulla was changed. Reserpine alone caused a monophasic increase lasting between 1-2 h; reserpine after dexamethasone caused a biphasic increase: the immediate response, lasting between 15 and 30 min, was followed by a secondary increase beginning 2-3 h after reserpine and lasting for several hours. The overall increase in cAMP content elicited by reserpine during the 8 h following injection remained unchanged or was even increased, depending on the dose of dexamethasone. Pretreatment with dexamethasone, which delayed the increase in cAMP, also delayed the activation and translocation of protein kinase and the induction of tyrosine hydroxylase caused by reserpine in adrenal medulla. The action of reserpine on the cAMP content of adrenal medulla required an intact innervation and did not appear to be related to increased secretion of ACTH from pituitary. In denervated adrenals reserpine failed to increase the cAMP content of the medulla but not that of the cortex.
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PMID:Association between the increase of cAMP content and the trans-synaptic induction of tyrosine hydroxylase in rat adrenal medulla. Studies with dexamethasone and reserpine. 1 21

Subcutaneous administration of ACTH 1-24 to mice increased the incorporation of [3H]lysine into brain and liver proteins, an effect which resembled that due to footshock. Corticosterone administration did not mimic these effects. ACTH 4-10 increased the [3H]lysine incorporation into brain or liver. These results are consistent with ACTH mediating the effects of footshock. However, dexamethasone decreased the brain responses to both footshock and ACTH, but while the liver response to ACTH was blocked, the footshock response was only diminished. This suggests a neural component in the response of the liver and possibly the brain. Intraventricular administration of ACTH 1-24 or ACTH 4-10 (D-phe), but not ACTH 4-10, increased [3H]lysine incorporation into brain protein. These neurochemical responses parallelled a distinctive pattern of behavior characterized by stretching, yawning and excessive grooming. Treatment for 3 days with long-acting preparations of ACTH 4-10, ACTH 4-10 (D-phe) or ACTH 1-24 increased the conversion of [3H]tyrosine into dopamine but not norepinephrine, alpha-MSH, beta-MSH or LVP had no such effect. Similar treatment with ACTH 4-10 or ACTH 1-24 increased striatal tyrosine hydroxylase activity measured in vitro, but did not significantly alter the enzyme activity from other brain regions. We conclude that ACTH peptides can stimulate protein and dopamine metabolism in mouse brain and that LVP has no such effects.
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PMID:Neurochemical responses of mice to ACTH and lysine vasopressin. 1 13

Hypophysectomy leads to a small increase in tyrosine hydroxylase activity of all brain areas containing noradrenergic neurons or tuberoinfundibular dopamine neurons, but nigroneostriatal dopamine neurons are not so affected. ACTH or corticosterone treatment inhibited this effect of hypophysectomy in some noradrenergic neurons and in tuberoinfundibular dopamine neurons. These data showing differential responsiveness of tyrosine hydroxylase in different brain areas are compatible with differences in regulation or molecular form of tyrosine hydroxylase in central noradrenergic and dopaminergic neurons. The disparity between increased hypothalamic tyrosine hydroxylase activity and decreased norepinephrine turnover following hypophysectomy may result from a change in the rate-limiting step to the hydroxylation of dopamine.
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PMID:Differential responsiveness of central noradrenergic and dopaminergic neuron tyrosine hydroxylase to hypophysectomy, ACTH and glucocorticoid administration. 2 50

Nerve growth factor (NGF) is a protein essential for the development and maintenance of the peripheral sympathetic nervous system, causing responsive neurones to increase in size and to extend neurites. Biochemically, the selective induction of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase key enzymes in catecholamine biosynthesis is one of its most characteristic effects. Both the morphological and biochemical effects are modulated by glucocorticoids, suggesting a close relationship between specific effects of NGF and hormone action. NGF has been shown to induce an increase in adrenal cyclic AMP in intact but not in hypophysectomised rats, and so we have looked directly at the effect of systemic administration of NGF on the hypothalamo-pituitary-adrenal axis. We report here that NGF induced an enhanced secretion of adrenocorticotropin (ACTH) and a prolonged increase in plasma glucocorticoid concentration after intravenous (i.v.) injection. Such effects could have important implications for the biological activity of NGF.
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PMID:Stimulation of the pituitary-adrenocortical axis by nerve growth factor. 4 Nov 86

Sympathetic ganglia from 13- to 15-day-old embryonic chicks were cultured for up to 2 days in Leighton tubes. The influence of hydrocortisone and ACTH added to the culture medium on the enzymes monoamine oxidase (MAO) and tyrosine hydroxylase was studied. Hydrocortisone (5 times 10(-5)M) had no effect on tyrosine hydroxylase but increased MAO activity by up to 46 percent over control values under conditions of low or zero nerve growth factor (NGF) concentration. ACTH also increased ganglionic MAO activity, the effect again depending on NGF concentration. This time the maximal response (an increase of 50 percent over controls) was seen at high NGF concentrations. This response was similar to the effect of 1 mM dibutyryl cyclic AMP, and was blocked by 1 times 10-5 M propranolol and 10 muM prostaglandin E(1). ACTH only slightly increased tyrosine hydroxylase activity and this effect was due to a small (18 percent) increase in sympathetic neurone number. Guanosine 5-diphosphate (0.5 mM) was found to increase tyrosine hydroxylase activity by 57 percent and this effect was blocked by the presence of ACTH.
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PMID:The effect of hydrocortisone and adrenocorticotrophic hormone on monoamine oxidase and tyrosine hydroxylase in explant cultures of embryonic chick sympathetic ganglia. 23 5

It was the aim of this study to investigate the mechanisms responsible for changes in 3',5'-cyclic adenosine monophosphate (cAMP) in the rat adrenal medulla occuring after administration of carbamylcholine, histamine, ACTH and various phenylethylamines. Carbamylcholine, ACTH, histamine, noradrenaline and dopamine produced marked (500-900%) increases in adrenal cAMP which were very similar in both adrenal cortex and medulla both with respect to time-course and relative extent. Interestingly isoprenaline and adrenaline did not influence cAMP levels even at excessively high doses. In all cases studied transsection of the splanchnic fibers supplying the adrenals reduced the increase in medullary cAMP by not more than 25--30%, suggesting that cAMP levels in the adrenal medulla are predominantly regulated by non-neuronal mechanisms. This assumption was strongly supported by the observation that hypophysectomy completely abolished the 500--600% increase in cAMP produced by 50 mumol/kg of dopamine and reduced the 700% increase resulting from 4.4 mumol/kg of carbamylcholine to 70%. In spite of the marked increase in cAMP produced by single and repeated doses of dopamine in the adrenal medulla there was no subsequent induction of tyrosine hydroxylase (TH). Moreover carbamylcholine (8.2 mumol/kg) evoked TH induction only in innervated adrenals whereas after denervation, in spite of the large (+ 500%) and prolonged (more than 90 min) increase in cAMP, no TH induction could be observed. It is concluded that adrenal medullary cAMP is predominantly regulated by the pituitary gland via the adrenal cortex and only to a much smaller extent--if at all--by direct cholinergic mechanisms, which are responsible for the initiation of TH induction.
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PMID:Effect of hypophysectomy on cAMP changes in rat adrenal medulla evoked by catecholamines and carbamylcholine. 24 Oct 24

Cells derived from the adrenal glands of duck embryos immediately prior to hatching were grown in culture and used to study the morphological and cytoskeletal changes and steroidogenic responses induced by 1-24 ACTH. Changes in the cytoskeletal components were observed by rhodamine-phalloidin staining for actin and by staining the tubulin immunoreactive components with FITC. The cultures were comprised of a small population of chromaffin cells and a larger population of steroidogenic cells. The chromaffin cells were distinguished by their tyrosine hydroxylase immunoreactivity. The steroidogenic cells were characterized by the presence of sudanophilic lipid droplets, numerous mitochondria, abundant smooth endoplasmic reticulum, microtubules distributed as a fairly even network throughout the cytoplasm, and microfilaments that formed an extensive and elaborate system of stress fibers with many parallel arrays. The cells readily responded to stimulation with ACTH by releasing corticosterone, aldosterone and deoxycorticosterone. Stimulation with ACTH also induced changes in both the cell morphology and the cytoskeleton. Exposure of the cells to Krebs-Henseleit buffer containing 1-24 ACTH caused them to form numerous fine filopodia, to lose their stress fibers, and to form a thick ring of actin at the periphery of the cell. In addition, many cells became extremely arborized with many long branched dendritic processes. The morphological changes appeared to be related to a redistribution of the actin components, and may be explained only in part by the rounding up or retraction of the cytoplasm. The results strongly suggest an involvement of the actin components of the cytoskeleton in the steroidogenic response to corticotropic stimulation.
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PMID:Cytoskeletal changes accompanying ACTH-induced steroidogenesis in cultured embryonic adrenal gland cells from the Pekin duck. 135 78

We have investigated putative dopaminergic regulation of opiomelanotropinergic activity in the arcuate/periarcuate mediobasohypothalamus (MBH) by assessing the changes in MBH tyrosine hydroxylase (TH; rate-limiting enzyme in catecholamine synthesis) and proopiomelanocortin (POMC; opiomelanotropin precursor) mRNA levels under conditions in which endogenous tuberinfundibular dopaminergic activity exhibits marked changes. Adult Sprague-Dawley rats were sacrificed at 09.00 and 15.00 h, and individual MBH POMC and TH cytoplasmic mRNA levels were simultaneously quantified by multiplex solution hybridization-RNase protection assay with protected fragments separated by polyacrylamide gel electrophoresis. In ovariectomized (OVX) rats treated for 3 days with low-dose estradiol (E2) implants (resulting in 18 +/- 4 pg E2/ml serum), the MBH levels of POMC and TH mRNAs were approximately 17 and 31% lower than those measured in OVX controls, respectively. In OVX rats implanted for 20 days with larger E2 implants (99 +/- 9 pg E2/ml serum), POMC and TH mRNA levels were approximately 29 and 41% lower than in OVX controls, respectively. Additional groups were exposed to the higher E2 dose for 20 days and then killed 10 or 20 days after removal of the E2 implant. In these rats, POMC mRNA levels rebounded to the same level seen in OVX controls, while TH mRNA levels even exceeded control values by 22-27%. TH and POMC mRNA levels did not change significantly between 09.00 and 15.00 h, except 10 days after removal of the E2 implants, when 09.00 h POMC mRNA levels were higher than the 15.00 h levels. MBH POMC and TH mRNA levels were positively correlated with each other within individual animals. This correlation is maintained when both POMC and TH mRNA levels are suppressed in response to both 3-day low-dose and 20-day high-dose E2 treatment. However, although rat MBH opiomelanotropinergic and tuberoinfundibular dopaminergic mRNA biosynthesis thus appear to be positively correlated, the coregulation or functional interactions of these two neuronal systems remain to be determined.
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PMID:Positive correlation between proopiomelanocortin and tyrosine hydroxylase mRNA levels in the mediobasohypothalamus of ovariectomized rats: response to estradiol replacement and withdrawal. 135 37


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