Increase of rat serum prolactin by adenosine analogs and their blockade by the methylxanthine aminophylline

Stewart, Sheila F.; Pugsley, Thomas A.

doi:10.1007/bf00634230

Cited by 10 publications

(6 citation statements)

References 27 publications

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“…This supports a previous study in which serum PRL levels were elevated at one time period, 35 min, following an intraperitoneal injection of these same adenosine analogs [16]. In our studies the agonists, ¿-PIA and NECA, resulted in a 10-fold increase in plasma PRL following infusion of low doses (2.5 nmol) into the third ventricle.…”

Section: Discussionsupporting

confidence: 79%

Central Actions of Adenosine on Pituitary Secretion of Prolactin, Luteinizing Hormone and Thyrotropin

Mw²,

Dd³

1989

Neuroendocrinology

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Pituitary hormones were measured in plasma in unanesthetized male and female rats prepared with venous and ventricular cannulae following ventricular infusions of adenosine and two adenosine receptor agonists. Adenosine (10, 100, and 200 nmol) injected intraventricularly caused dose-related rises in plasma prolactin (PRL) in males; in females, only the 100- and 200-nmol doses increased PRL. Similar doses of adenosine had little effect on plasma levels of luteinizing hormone (LH) and thyrotropin (TSH) in the same animals. The adenosine receptor agonists L-N⁶-phenylisopropyladenosine (L-PIA) and 5’-N-ethyl-carboxamideadenosine (NECA) potently stimulated prolactin secretion at doses of 10 and 50 nmol when administered into the lateral ventricle, and at a dose of 2.5 nmol when administered into the third ventricle. The secretion of PRL was antagonized by the adenosine receptor antagonist theophylline (25 nmol), when theophylline was coadministered with NECA and L-PIA. TSH levels were reduced slightly but significantly following the 10- and 50-nmol infusions of L-PIA into the lateral ventricle. The less potent D-isomer of PIA (D-PIA) did not significantly stimulate PRL release. Coupled with studies indicating the presence of adenosine in the basal hypothalamus, our observations indicate a potential neuroendocrine role for this purine in prolactin secretion.

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Section: Discussionsupporting

confidence: 79%

Central Actions of Adenosine on Pituitary Secretion of Prolactin, Luteinizing Hormone and Thyrotropin

Mw²,

Dd³

1989

Neuroendocrinology

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“…A number of authors have shown that peripheral [67] or central [68] administration of adenosine can stimulate the release of PRL but not LH [68] or TSH [69]. These data, however, gave little insight into the site or mode of action of adenosine in the neuroendocrine system, and could in fact represent non-specific stressful actions.…”

Section: Biological Effects Of Purines In the Pituitary Gland Effectsmentioning

confidence: 99%

Novel insights into how purines regulate pituitary cell function

2003

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Purine nucleosides and nucleotides are widely distributed substances that exhibit a diverse range of effects in a number of tissues, acting as important extracellular signalling molecules in addition to their more established roles in cellular metabolism. They mediate their effects via activation of distinct cell surface receptors, termed adenosine (or P1) and P2 purinergic receptors. Although roles for adenosine and adenine nucleotides have been described previously in the pituitary gland, the distribution of the receptor subtypes and the effects of their activation on pituitary function are not well defined. Recent evidence, however, has emerged to describe a complex signalling system for purines in the pituitary gland. Data from a variety of studies have shown that the expression pattern, number and affinity of adenosine and/or P2 receptors may be cell-type specific and that non-endocrine in addition to endocrine cells elaborate these receptors. These variations, along with the diverse range of signalling pathways activated, dictate the response of individual cell types to extracellular purines, with roles now emerging for these substances in the regulation of hormone release, pituitary cell proliferation and cytokine/growth factor expression. In this review, we discuss these advances and examine some implications for pituitary growth control and the response of the hypothalamic-pituitary-adrenal axis to stress and inflammation.

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“…However, these effects were only apparent at very high concentrations of the nucleoside and were mimicked by guanosine. Others later showed that adenosine could stimulate the release of PRL when given peripherally (Stewart & Pugsley 1985) or centrally (Ondo et al 1989), but not of luteinising hormone (LH) (Ondo et al 1989) or thyrotrophin (TSH) (Di Renzo et al 1990). The effects of xanthines, such as caffeine, theobromine and denbufylline, which act as adenosine receptor antagonists, have also been examined in the pituitary gland.…”

Section: Effects Of Adenosine On Pituitary Hormone Releasementioning

confidence: 99%

Adenosine signalling pathways in the pituitary gland: one ligand, multiple receptors

Rees

Scanlon²,

Ham³

2003

Journal of Endocrinology

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Adenosine receptors are widely distributed in most species and mediate a diverse range of physiological and pathological effects. Although adenosine receptors have been identified in the pituitary gland, the distribution of the individual subtypes (A 1 , A 2A , A 2B , A 3 ) has not been well defined. Furthermore, the effects of adenosine on pituitary trophic activity and function are not well established despite good evidence for growth-and immunemodulating properties of the nucleoside elsewhere.Recent advances have provided a more detailed description of adenosine receptor distribution and function in the anterior pituitary and this commentary reviews these observations and highlights some of the possible implications in relation to the control of the hypothalamicpituitary-adrenal axis and the regulation of inflammation and pituitary cell growth.

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Increase of rat serum prolactin by adenosine analogs and their blockade by the methylxanthine aminophylline

Cited by 10 publications

References 27 publications

Central Actions of Adenosine on Pituitary Secretion of Prolactin, Luteinizing Hormone and Thyrotropin

Central Actions of Adenosine on Pituitary Secretion of Prolactin, Luteinizing Hormone and Thyrotropin

Novel insights into how purines regulate pituitary cell function

Adenosine signalling pathways in the pituitary gland: one ligand, multiple receptors

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