Temporary increase of plasma epinephrine affects stress responses 24 h later

Porta, S.; Epple, August; Květňanský, Richard; Leitner, G.; Emsenhuber, W.; Radkohl, W.

doi:10.1016/0031-9384(95)00041-g

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…BAT NE was measured by techniques described elsewhere (17). Brie¯y, BAT was homogenized at 4 8C in perchloric acid, EDTA and ascorbic acid and centrifuged for 10 min at 24 000 g. Supernatants were treated with ammonium chloride, EDTA and a diphenylborate±ethanolamine complex, and also with octanol±heptane and a tetraoctylamino±bromide complex.…”

Section: Ne Measurementmentioning

confidence: 99%

The in vivo effects of beta-3-receptor agonist CGP-12177 on thyroxine deiodination in cold-exposed, sympathectomized rat brown fat

Hofer

Raı́ces²,

Schauenstein³

et al. 2000

European Journal of Endocrinology

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Objective: The effects of the beta-3-receptor agonist CGP-12177 on thyroxine (T4) deiodination in sympathectomized (SX) interscapular brown adipose tissue (BAT) were assessed in 300 g body weight (BW) Wistar rats. Design: Seven days after SX, groups of rats were implanted s.c. with pellets containing 5 mg CGP-12177 or 5 mg norepinephrine (NE) and were immediately placed at 4 8C for 24 h. Other SX groups were injected with CGP-12177 or NE 1 mg/kg BW i.p. and placed in the cold for 4 h. The latter group was injected, in addition, with prazosin 0.4 mg/100 g BW i.p. or propranolol 0.5 mg/100 g BW i.p. 15 min before and 2 h after the administration of CGP-12177 or NE. Methods: Two hours after the last injection of prazosin or propranolol, animals were killed and BAT was removed, homogenized and centrifuged at 500 g for 10 min at 4 8C. The infranatants were incubated during 60 min in the presence of dithiothreitol and 1 mCi [ 125 I]T4. Aliquots were chromatographed on paper for the measurement of [ 125 I]T4 and its deiodinated subproducts. Results: CGP-12177 restored normal T4 deiodination in SX BAT from both groups, but NE was slightly more effective. Propranolol, although not prazosin, blocked the CGP-12177 effects. Contrariwise, the NE-induced rise in deiodination was blocked by prazosin and to a lesser extent by propranolol. Conclusions:The results indicate that CGP-12177 stimulated the in vivo activation of 5 H -deiodinase type II activity predominantly via beta-3-receptor, without participation of alpha-1-receptors.

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Section: Ne Measurementmentioning

confidence: 99%

The in vivo effects of beta-3-receptor agonist CGP-12177 on thyroxine deiodination in cold-exposed, sympathectomized rat brown fat

Hofer

Raı́ces²,

Schauenstein³

et al. 2000

European Journal of Endocrinology

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“…Because adrenaline still increases at least severalfold in response to hypoglycemia even in patients with severe counterregulatory failure, patients with repeated hypoglycemic events may have chronically elevated adrenaline levels. Animal studies have indicated that prior elevation of adrenaline (18) and repeated stress (which primarily stimulates adrenaline) (19) down-regulate sympathetic responses to novel stress, whereas prior exposure to ␤-adrenergic agonists (20,21) and strenuous exercise (22) reduce ␤-adrenergic sensitivity. Based on these data, we hypothesized that the adrenaline response to antecedent hypoglycemia may contribute to the hypoglycemia unawareness syndrome by exerting a down-regulating effect on adrenaline responses to and adrenergic sensitivity during subsequent hypoglycemia.…”

mentioning

confidence: 98%

Antecedent Adrenaline Attenuates the Responsiveness to But Not the Release of Counterregulatory Hormones during Subsequent Hypoglycemia

Galan

Rietjens

Tack

et al. 2003

The Journal of Clinical Endocrinology &Amp; Metabolism

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Hypoglycemia unawareness is thought to be the consequence of recurrent hypoglycemia, yet the underlying mechanism is still incompletely understood. The aim of the present study was to determine the role of antecedent elevated adrenaline in the pathogenesis of hypoglycemia unawareness. Sixteen healthy volunteers (eight of either sex) participated in two experiments, performed in random order and at least 3 wk apart. During the morning, three consecutive doses of 0.04, 0.06, and 0.08 microg.kg(-1).min(-1) of adrenaline or matching placebo (normal saline) were infused for the total duration of 1 h. Three hours later, a hyperinsulinemic (360 pmol.m(-2).min(-1)) two-step hypoglycemic (5.0-3.5-2.5 mmol.liter(-1)) clamp study was performed. During hypoglycemia, hypoglycemic symptoms, counterregulatory hormones, cardiovascular responses, and cognitive function were monitored. Hypoglycemia induced similar responses of autonomic and neuroglycopenic symptoms, counterregulatory hormones, and lengthening in reaction time on the choice reaction time task, irrespective of antecedent infusions. However, prior adrenaline was associated with higher exogenous glucose requirements at hypoglycemic nadir (10.1 +/- 1.3 vs. 7.3 +/- 1.3 micromol.kg(-1).min(-1), P = 0.017), an attenuated hypoglycemia-induced fall in blood pressure (mean arterial pressure, -13 +/- 2 vs. -8 +/- 2 mm Hg, P = 0.006), and preserved cognitive function as assessed by the symbol digit test during hypoglycemia, when compared with prior placebo. We conclude that elevated adrenaline attenuates the responsiveness to, but not the release of counterregulatory hormones during subsequent hypoglycemia. As such, adrenaline's role in the development of hypoglycemia unawareness is limited.

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Pfragner¹,

Behmel

Smith

et al. 1998

Journal of Neurocytology

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Pheochromocytomas are rare tumours, with an incidence of 1-2 per million which arise from chromaffin cells of the adrenal medulla. They occur sporadically or as part of dominantly inherited cancer syndromes like multiple endocrine neoplasia 2 (MEN2A and 2B) and others. Continuous cell lines, not available so far, are essential tools for studies in these tumours. A continuous cell line (KNA) was established from a sporadic pheochromocytoma of the right adrenal gland of a 73-year-old woman. The KNA cells grow as suspensions of spheroids and show the morphological and immunocytochemical characteristics of neuronal chromaffin cells, such as neuroendocrine granules, and positive reactions to chromogranin- and related peptide-, neuron specific enolase and vasoactive intestinal peptide antibodies. Neurite-like processes are formed after addition of nerve growth factor. Chromosomal analyses revealed a diploid (46,XX,n = 50) to hypodiploid (43-45,XX,n = 15) karyotype. In hypodiploid metaphases most frequently #19, #17, #21 and #22 were missing. Chromosome arms 1p and 4q showed apparently consistent interstitial deletions: 6q, 8q, 13q and 22q showed clonal interstitial deletions. The cell line shows a heterozygous sequence variant TGC (cysteine) to TGG (tryptophan) in codon 611 in exon 10 of the RET proto-oncogene. So far, PC-12, a rat adrenal pheochromocytoma, has been the only continuous pheochromocytoma cell line available. KNA represents the first report on a human continuous pheochromocytoma cell line, the first report of structural chromosome aberrations in pheochromocytomas and the first report of a RET mutation TGC to TGG in exon 10 of the RET proto-oncogene in a sporadic pheochromocytoma.

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Temporary increase of plasma epinephrine affects stress responses 24 h later

Cited by 3 publications

References 15 publications

The in vivo effects of beta-3-receptor agonist CGP-12177 on thyroxine deiodination in cold-exposed, sympathectomized rat brown fat

The in vivo effects of beta-3-receptor agonist CGP-12177 on thyroxine deiodination in cold-exposed, sympathectomized rat brown fat

Antecedent Adrenaline Attenuates the Responsiveness to But Not the Release of Counterregulatory Hormones during Subsequent Hypoglycemia

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