Stereospecificity of the dopamine receptor mediating the growth hormone response to apomorphine in man

S, Lal; Np, Nair; Jx, Thavundayil; Tawar,; Quirion, Rémi; Guyda, H.

doi:10.1007/bf01244707

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…Both stimulatory and inhibitory dopaminergic effects on the somatotrophic system have been reported. Basal GH secretion in healthy subjects is stimulated by DA (14, 15, 18, 28), dopaminergic agonists (19, 28, 29) and l ‐dopa (21, 22, 30). The stimulatory actions of l ‐dopa appear to persist in patients with IPD (2, 3), although an acquired defect in release of GH following years of l ‐dopa therapy has also been reported (25).…”

Section: Discussionmentioning

confidence: 99%

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

Schaefer

Vogt

Nowak³

et al. 2007

J Neuroendocrinology

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Idiopathic Parkinson’s disease and dopaminergic medication may influence pituitary hormone secretion. The present study aimed to reveal any abnormalities of the somatotrophic system induced by the disease itself and/or the dopaminergic therapy. Investigations of other pituitary hormones under basal and stimulated conditions, as well as an analysis of body composition, were also performed. This was a controlled diagnostic study in which luteinising hormone‐releasing hormone, thyroid‐releasing hormone, corticotrophin‐releasing hormone and arginine hydrochloride were administered to ten patients with idiopathic Parkinson’s disease under dopaminergic medication. Basal and stimulated hormone concentrations and bioelectrical impedance analyses were compared with those of healthy, age‐matched controls. Basal growth hormone (GH) at −30 and 0 min was higher in Parkinsonian patients (2.74 ± 3.79 ng/ml versus 0.53 ± 0.10 ng/ml and 2.12 ± 2.44 ng/ml versus 0.51 ± 0.03 ng/ml; P < 0.05). The area under the GH curve after stimulation was greater in Parkinsonian patients (502.4 ± 202.6 ng × min/ml versus 312.0 ± 98.5 ng × min/ml; P < 0.05), depending on higher basal GH levels, rather than a greater arginine response. No differences in insulin growth factor (IGF)‐1 or IGF‐BP3 concentrations were detected. There were no differences between the groups in basal and stimulated gonadotrophic, corticotrophic and thyrotrophic function, or body composition. Prolactin was below the detection limit in the patients during the course of the study. Parkinsonian patients experience marked hypoprolactinaemia and repeated stimulation of GH secretion during chronic dopaminergic therapy. Our findings suggest a peripheral GH resistance in these chronically‐treated patients.

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Section: Discussionmentioning

confidence: 99%

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

Schaefer

Vogt

Nowak³

et al. 2007

J Neuroendocrinology

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“…During withdrawal, the number increases to above-normal levels (rebound phenomenon; Rommelspacher et al, 1992). Moreover, there is evidence that GH release after dopaminergic stimulation depends upon the interaction of dopamine D2-receptors (Tallo and Malarkey, 1981;Fabbrini et al, 1988;Lal et al, 1991) with G-proteins (Bunzow et al, 1988;Enjalbert et al, 1988;Landis et al, 1989). It has been observed that G-protein levels are reduced during chronic intoxication (Mochly-Rosen et al, 1988;Wand and Levine, 1991;Diehl et al, 1992).…”

Section: Introductionmentioning

confidence: 96%

Evidence for prolonged recovery of dopaminergic transmission after detoxification in alcoholics with poor treatment outcome

Heinz

Lichtenberg-Kraag

Baum

et al. 1995

J. Neural Transmission

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It has been hypothesized that dysfunction of dopaminergic neurotransmission is involved in the pathogenesis of alcohol addiction. Therefore, peripheral dopamine levels, sensitivity of central dopamine receptors (apomorphine-induced Growth Hormone (GH) secretion), and the inhibitory efficacy of G-proteins on adenylyl cyclase activity (as an indicator for dopamine D2-receptor coupled second messenger mechanisms) were measured in 45 alcohol-dependent patients before and after detoxification and in 10 healthy controls. The time needed to adjust to abstinence conditions differed between patients with good and poor treatment outcome. In subsequent abstainers, effects of alcohol withdrawal were already found during the first 24 hours of abstinence (normalisation of GH response, increases in dopamine levels and the inhibitory efficacy of G-proteins). During the next 7 days of abstinence, no more significant changes were observed in the assessed variables. In subsequent relapsers, no significant effect of acute ethanol withdrawal on the same measures was found. However, at day 8 of abstinence, increases in apomorphine-induced GH secretion (towards normalisation), in dopamine plasma levels, and in the inhibitory efficacy of G-proteins (towards above-normal levels) were observed. This retarded adjustment of dopaminergic signal transduction seems to reflect the relapse risk of treatment nonresponders.

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Stability of apomorphine hydrochloride in aqueous sodium bisulphite solutions

Kin

Lal

Thavundayil

2001

Progress in Neuro-Psychopharmacology and Biological Psychiatry

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Stereospecificity of the dopamine receptor mediating the growth hormone response to apomorphine in man

Cited by 5 publications

References 28 publications

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

Evidence for prolonged recovery of dopaminergic transmission after detoxification in alcoholics with poor treatment outcome

Stability of apomorphine hydrochloride in aqueous sodium bisulphite solutions

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