Role of Monoamines in the Control of Growth Hormone and Prolactin Secretion in Man and Rats

Imura, H; Kato, Yukiko

doi:10.1159/000395586

Cited by 2 publications

(4 citation statements)

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“…The control of growth hormone secretion is complex: it has been suggested that adrenergic mechanisms participate as well as dopaminergic and serotoninergic mechanisms (Imura & Kato, 1974) but the present findings lend no support to this.…”

Section: Discussioncontrasting

confidence: 91%

“…We have previously reported that oxprenolol did not alter prolactin levels in patients with essential hypertension (Lewis et al, 1979) but only single samples at clinic attendances were measured in that study. Little has been known of the role of beta adrenoceptors in controlling prolactin secretion, though isoprenaline infusion has been reported to increase prolactin levels (Imura & Kato, 1974). Chronic treatment of rats with propranolol can result in increased brain levels of dopamine (Morinan & Leonard, 1977) which in turn could reduce prolactin secretion (del Pozo & Fluckiger, 1973), and some B-adrenoceptor blockers affect 5-hydroxytryptamine receptors which might influence prolactin secretion through this possible relationship remains unresolved (Frantz, 1979).…”

Section: Discussionmentioning

confidence: 99%

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The effects of propranolol and acebutolol on the overnight plasma levels of anterior pituitary and related hormones.

Mj¹,

Groom²,

Barber³

et al. 1981

Brit J Clinical Pharma

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1 The effects of single evening doses of the beta‐adrenoceptor blocking agents propranolol (80 mg orally) and acebutolol (200 mg orally) on plasma levels throughout the night of prolactin, growth hormone, luteinising hormone, follicle stimulating hormone, cortisol and testosterone have been studied in seven healthy male volunteers. 2 Three way analysis of variance showed that acebutolol significantly reduced circulating levels of prolactin and follicle stimulating hormone, but did not alter the levels of the other hormones studied. 3 Propranolol significantly reduced follicle stimulating hormone and testosterone, and significantly increased circulating levels of cortisol, but caused no change in the other hormones studied. 4 Prolactin, luteinising hormone, testosterone and cortisol showed a significant variation with time indicating the existence of a diurnal rhythm in the pattern of their secretion. 5 There was a significant inter‐subject variability in all the hormones studied. 6 There was a significant between‐subject variation in response to both propranolol and acebutolol. 7 Different subjects showed significant variations with respect to time in prolactin, growth hormone and cortisol levels. 8 Neither propranolol nor acebutolol significantly altered the time course of secretion of any of the hormones studied. 9 Possible relationships of these beta‐adrenoceptor blocker‐induced changes in anterior pituitary and related hormones to the antihypertensive mechanism of acebutolol and propranolol are discussed.

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Section: Discussioncontrasting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

The effects of propranolol and acebutolol on the overnight plasma levels of anterior pituitary and related hormones.

Mj¹,

Groom²,

Barber³

et al. 1981

Brit J Clinical Pharma

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“…Brain monoamines, such as norepinephrine, dopamine and serotonin, play an important role in regulating GH se cretion [9,12,19,22] and depletion of these brain amines by reserpine or inhibition of the synthesis of catecholamines by a-methyl-p-tyrosine (a-MPT) reportedly inhibit episodic GH secretion [5,6] in conscious rats. Spontaneous GH bursts are also inhibited by DDC [23], a dopamine-P-hydroxylase inhibitor.…”

Section: Discussionmentioning

confidence: 99%

“…Intraventricular administration of P-endorphin (5 pg/rat) also in creased the plasma GH levels which were lowered by phenoxybenzamine. These findings suggest that a-adrenergic me chanisms are involved in GH release induced by opioid peptides in the rat.Although there is accumulating evidence that both brain amines and small peptides present in the central nervous system influence the secretion of growth hormone (GH) [9,12,19,22], nevertheless, the relationship between biogenic amines and neuropeptides is poorly understood.Morphine stimulates GH release in the rat, possibly by acting through opiate receptors in the central nervous sys tem [18,21]. Identification of neuropeptides with opiate like activity led to the observations that opioid peptides such as P-endorphin, a-endorphin and Met5-enkephalin, stimulate GH secretion in the rat [4,13,24], We previously reported that GH secretion is stimulated also by FK 33-824, a potent Met5-enkephalin analog [25], given intravenously or intraventricularly into the anesthetized rat [14,15].…”

mentioning

confidence: 99%

Involvement of Alpha-Adrenergic Mechanisms in Growth Hormone Release Induced by Opioid Peptides in Conscious Rats

et al. 1981

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The effects of synthetic enkephalin analog (FK 33–824) and β-endorphin on growth hormone (GH) secretion and their interaction with brain monoamines were investigated in unanesthetized male rats. Blood samples (0.4 ml each) were withdrawn every 10–20 min for 6 h from a catheter chronically implanted in the right atrium. In all control rats, immunoreactive GH secretion was pulsatile in nature and two major GH bursts were found to occur around 12.00 and 15.30.The opioid peptides were injected between bursts at 14.00. Following an intravenous administration of FK 33–824 (10 μg/100 g b.w.), there was an abrupt increase in plasma GH, which was significantly suppressed by naloxone (125 μg/ 100 g b.w., i.v.), a specific opiate antagonist. Pretreatment with reserpine (1 mg/100 g b.w., i.p.) abolished not only the natural GH burst but also the GH response to FK 33–824. Pretreatment with dopamine-β-hydroxylase inhibitors, diethyldithiocarbamate (DDC, 100 mg/100 g b.w., i.v.) and fusarate (10 mg/100 g b.w., i.v.) also inhibited the natural GH burst and GH rise induced by FK 33–824. Intravenous injection of clonidine (15 μg/100 g b.w.), an α-adrenergic stimulant, resulted in an increase in plasma GH in the rats pretreated with reserpine, DDC or fusarate. Phenoxybenzamine (1 mg/100g b.w., i.v.), an α-adrenergic blocking agent, inhibited the GH response to FK 33–824. On the other hand, GH release induced by FK 33–824 was not influenced by propranolol (1 mg/100 g b.w., i.v.), a β-adrenergic blocking agent, nor pimozide (0.1 mg/100g b.w., i.v.), a dopamine antagonist. Intraventricular administration of β-endorphin (5 μg/rat) also increased the plasma GH levels which were lowered by phenoxybenzamine. These findings suggest that α-adrenergic mechanisms are involved in GH release induced by opioid peptides in the rat.

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Role of Monoamines in the Control of Growth Hormone and Prolactin Secretion in Man and Rats

Cited by 2 publications

References 0 publications

The effects of propranolol and acebutolol on the overnight plasma levels of anterior pituitary and related hormones.

The effects of propranolol and acebutolol on the overnight plasma levels of anterior pituitary and related hormones.

Involvement of Alpha-Adrenergic Mechanisms in Growth Hormone Release Induced by Opioid Peptides in Conscious Rats

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