...Kathryn Becker; Susan Stegenga; Sonya Conway In vivo and in vitro (static incubation and perifusion) procedures were used to examine the role of insulin-like growth factors (IGFs) in growth hormone (GH) feedback. An α 2 -adrenergic agonist, clonidine (CLON; 2 × 10 -8 M in vitro or 30 µg/ml/kg body...

... (GH) responses to exogenous GH-releasing factor (GRF; 3 µg/kg i.v.) or clonidine (CLO; 100 µg/kg i.v.), either given alone or in combination, were tested in 3-month-old male rats made GH-releasing hormone (GH-RH) deficient neonatally by administration of monosodium glutamate (MSG; 4 mg/g body weight...

... modification of their frequency. This is most apparent at the time of maximal inflammation, i.e. 14–21 days after inoculation of the adjuvant. GH responsiveness to a maximal dose of clonidine (10 µg/100 g body weight, BW), a secretagogue known to act at the hypothalamic level, is comparable in AIA and control...

...Carmela Netti; Valeria Sibilia; Francesca Guidobono; Antonio Pecile The effects of histamine (HA) and of (R) α-methyl-histamine (α-MeHA; a drug that decreases histaminergic tone through activation of presynaptic H 3 receptors) on growth hormone (GH) secretion induced by clonidine (CLO), an α 2...

...-releasing hormone (GRF, 3 µg/kg i.v.) or clonidine (CLO, 100 µg/kg, i.v.), either given alone or in combination, were tested in male rats in which norepinephrine synthesis had been previously blocked with the dopamine-β-hydroxylase inhibitor diethyldithiocarbamate (DDTC, 400 mg/kg i.p.). These experiments...

... lordosis in OVX guinea pigs primed with estradiol benzoate (EB) alone and facilitate lordosis in OVX females primed with EB and P. In this study, we examined the regional specificity of this regulation by infusing the alpha-adrenergic agonist clonidine (CLON) or the alpha-adrenergic antagonist phentolamine...

...Silvano G. Cella; Victor M. Arce; Francesco Pieretti; Vittorio Locatelli; Beatriz P. Settembrini; Eugenio E. Müller We have studied in old dogs the effects of short-term administration of growth hormone (GH)-releasing hormone (GHRH) alone or co-administered with clonidine (CLO), an ct2-adrenergic...

...Bálint Kacsóh; Béla E. Tóth; Clark E. Grosvenor The effects of the α 2 -agonist clonidine (CLO), the serotonin (5-HT) precursor 5-hydroxy-L-tryptophan (5-HTP), the 5-HT 2 /histamine (H 1 ) antagonist cyproheptadine (CYPRO), the muscarinic cholinergic antagonist atropine (ATR), and an affinity...

... neurons through α 2 -adrenoreceptors, while inhibiting their own secretion acting on presynaptic α 2 receptors. In this study the effect of the α 2 -agonist clonidine and the antagonist CH-38083 was studied on exogenous CRF-41/AVP-induced ACTH secretion in rats with/without paraventricular nucleus lesion...

... increased GH release when given individually. Combinations of clonidine, 6 and 30 µg/kg, and the serotonin agonist quipazine 160 µg/kg had an additive effect on GH release. Almost all combinations of morphine, 40 and 200 µg/kg, with clonidine and quipazine stimulated GH release, but this release was less...

..., conscious male rats were given unilateral intrahypothalamic injections of clonidine, the serotonin agonist quipazine and a µ opioid agonist (DAGO), and plasma GH levels were measured. Injection of all three drugs separately into the mediobasal hypothalamus (MBH) increased GH release. Combinations of DAGO...

...Do Thanh Kiem; Levente Bartha; László G. Hársing, Jr.; Gábor B. Makara The relationship between opioidergic and alpha 2 -adrenergic system in the regulation of GH secretion was studied using a novel alpha 2 -antagonist, CH-38083, and chronic treatment with yohimbine or clonidine. In male Wistar...

... peak of 14.5 ± 3.8 ng/ml (control) that was potentiated by Dex 4 mg i.v. administered 3 h before (26.4 ± 6.8 ng/ml). On the contrary, longer Dex treatments suppress GHRH-induced GH values (6.0 ± 1.1 ng/ml after Dex 8 mg and 1.8 ± 0.3 ng/ml after Dex 22 mg). Clonidine administration 300 µg p.o. (n = 7...

...De Thanh Kiem; Ervin Stark; Mårton I.K. Fekete The effect of testosterone on the growth hormone (GH)-releasing and hypotensive actions of clonidine was evaluated in vivo using male Wistar rats. Clonidine at various doses and by various routes (5 µg/kg, Lev.; 15 µg/kg, i.v., and 7, 15, 31, 125...

... tests, clonidine (0.25 mg/kg, 6 min pretest) induced a profound deficit in intromissive and ejaculatory behavior whereas naloxone (5 mg/kg, 20 min pretest) evinced a facilitation of ejaculatory behavior, evidenced by decreases in the ejaculation latency in the initial copulatory series and by decreases...

... agonist clonidine (150 µg/kg, i.p.) was used to inhibit central NNA and to examine the role of α 2 -adrenoceptors in the actions of serotoninergic drugs. Computerized mass spectrometry was employed to specifically and precisely assay hypothalamic norepinephrine (NE), 3,4-dihydroxyphenylethyleneglycol...

...Thomas O. Bruhn; Patrick A. Tresco; Gregory P. Mueller; Ivor M.D. Jackson The role of β-endorphin in the stimulation of growth hormone secretion elicited by administration of clonidine (Clon), an α 2 -adrenergic agonist, was investigated in awake, freely moving male rats. Animals were infused...

... in this steroid-dependent behavior. Neither of the α 1 -agonists, phenylephrine or methoxamine, significantly facilitated lordosis in ovariectomized females primed with 10 µg of estradiol benzoate for 1 or 3 days. Animals exhibiting estrogen plus clonidine-facilitated lordosis showed a decrease in the behavior...

... infusions of noradrenergic and cholinergic compounds modulated ethanol-induced and stress-induced adrenocortical responses differentially in these mice. Clonidine, an α 2 -adrenergic agonist, blocked ethanol-induced elevations in plasma corticosterone in a dose-dependent manner (1 and 10 µg) in LS mice...

...Elaine R. Peskind; Murray A. Raskind; Rosemary D. Leake; Gore Ervin; Michael G. Ross; Daniel M. Dorsa To evaluate the oα-noradrenergic regulation of arginine vasopressin (AVP) and oxytocin (OT) in normal humans, we measured the effect of the α 2 -agonist clonidine on concentrations...