Opioid-Receptor Blockade Blunts Growth Hormone (GH) Secretion Induced by GH-Releasing Hormone in the Human Male

Tomasi, Paolo; Fanciulli, Giuseppe; Palermo, Mario; A, Pala; Demontis, M A; Delitala, G.

doi:10.1055/s-2007-978827

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…Naloxone infusion decreased GHRHinduced GH release in healthy women but had no effect in normal men (96). On the other hand, in another study, naloxone significantly blunted the GH response to GHRH in healthy male volunteers (97).…”

Section: :4 R189 Reviewmentioning

confidence: 90%

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

Fountas

Chai

Kourkouti

et al. 2018

European Journal of Endocrinology

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The use of opioids has grown substantially over the past two decades reaching the dimensions of a global epidemic. These drugs have effects on multiple levels of the endocrine system through mechanisms which are still not fully elucidated, and awareness of their endocrine sequelae is vital for all specialists prescribing or managing patients on them. Hypogonadism is the most well recognised consequence of opioid use (prevalence 21-86%) which, however, may remain undiagnosed with potential adverse outcomes for the patients. Although less frequent, cortisol deficiency can be also found. Furthermore, there is negative impact on bone health (with reduced bone mineral density and increased fracture risk) and occasionally hyperprolactinaemia, whereas the clinical significance of alterations in other hormones remains to be clarified. Discontinuation or reduction of the opioid and, in cases of chronic pain, consideration of alternative therapies for pain relief are potential management options. Hormonal replacement, especially when the above measures are not practically feasible, needs to be considered. Further studies are needed to clearly establish the prevalence of hormonal abnormalities with various regimes, doses and routes of opioids and to address reliably the long-term benefits and risks of hormonal treatment in patients on opioids. Until evidence-based, safe and cost-effective clinical guidelines become available, periodical assessment of the gonadal and adrenal function (particularly when relevant clinical manifestations are present) and evaluation of the bone health status are advised.

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Section: :4 R189 Reviewmentioning

confidence: 90%

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

Fountas

Chai

Kourkouti

et al. 2018

European Journal of Endocrinology

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“…While the mechanism is not completely clear, its plausible that decreased venous outflow during BRF reduces clearance of metabolic acidosis resulting in activation of proton-activated nociceptors [42]. Importantly, acute pain is known to regulate GH secretion through stimulation of opioid receptors [43]. For example, Greisen and coworkers found a significant increase in GH secretion following electrical stimulation to the abdominal skin [44].…”

Section: Discussionmentioning

confidence: 99%

Growth hormone responses to acute resistance exercise with vascular restriction in young and old men

Manini

Yarrow

Buford

et al. 2012

Growth Hormone & IGF Research

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Objective Resistance exercise (RE) stimulates growth hormone (GH) secretion in a load-dependent manner, with heavier loads producing larger GH responses. However, new research demonstrates that low-load RE performed with blood flow restriction (BFR) produces potent GH responses that are similar to or exceed those produced following high-load RE. We hypothesized that low-load RE with vascular restriction would attenuate the known age-related reduction in GH response to RE. Design In a randomized crossover design, ten young (28±7.8 years) and ten older (67.4±4.6 years) men performed bilateral knee extension RE with low-load [20% of one-repetition maximum (1RM)] with BFR and high-load (80% 1RM) without BFR. GH and lactate were measured every 10 minutes throughout a 150-minute testing session (30 minutes prior to and 120 minutes following completion of the exercise); IGF-I was measured at baseline and 60 minutes post-exercise. Results Area under the GH curve indicated that both age groups responded similarly to each exercise condition. However, young men had a significantly greater maximal GH response to low-load RE with BFR than the high-load condition without BFR. Additionally, younger men had greater maximal GH concentrations to low-load RE with BFR than older men (p=0.02). The GH responses were marginally correlated to lactate concentration (r=0.13, p=0.002) and IGF-I levels were unchanged with RE. Conclusions GH responses to low-load RE with vascular restriction are slightly higher than high-load RE without vascular restriction in young men. However, low-load RE with vascular restriction did not attenuate the known age-related reduction in GH response with exercise. These data suggest that while low-load RE with vascular restriction is as effective for inducing a GH response than traditionally-based high-load RE, there is a more potent response in young men.

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“…The lack of an antidyskinetic effect of naloxone cannot be due simply to an ineffective dose being administered, as naloxone significantly extended the action of L ‐dopa. The dosing regime of naloxone used is similar to previous protocols employed to produce blockade of opioid receptors for between 2 and 24 hours 32–36. In addition, the patient who unfortunately developed an opioid withdrawal‐like reaction suggests that efficient blockade of opioid receptors occurred at the dose employed.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, intravenous (i.v.) naloxone has been employed widely to demonstrate opioid actions in man and administration regimens that provide opioid receptor antagonism over several hours gave no reported adverse effects 32–36…”

mentioning

confidence: 99%

Non‐subtype‐selective opioid receptor antagonism in treatment of levodopa‐induced motor complications in Parkinson's disease

et al. 2003

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Opioid peptide transmission is enhanced in the striatum of animal models and Parkinson's disease (PD) patients with levodopa-induced motor complications. Opioid receptor antagonists reduce levodopa-induced dyskinesia in primate models of PD; however, clinical trials to date have been inconclusive. A double-blind, placebo controlled, crossover design study in 14 patients with PD experiencing motor fluctuations was carried out, using the non-subtype-selective opioid receptor antagonist naloxone. Naloxone did not reduce levodopa-induced dyskinesia. The duration of action of levodopa was increased significantly by 17.5%. Non-subtype-selective opioid receptor antagonism may prove useful in the treatment of levodopa-related wearing-off in PD but not in dyskinesia.

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Opioid-Receptor Blockade Blunts Growth Hormone (GH) Secretion Induced by GH-Releasing Hormone in the Human Male

Abstract: Naloxone is able to decrease the effect of a maximal dose of GHRH, thus suggesting the existence of an opioid stimulatory tone on GH secretion.

Cited by 8 publications

References 15 publications

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

MECHANISMS OF ENDOCRINOLOGY: Endocrinology of opioids

Growth hormone responses to acute resistance exercise with vascular restriction in young and old men

Non‐subtype‐selective opioid receptor antagonism in treatment of levodopa‐induced motor complications in Parkinson's disease

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