In vivo Supersensitivity of the Anterior Pituitary of Old Female Rats to Dopaminergic Inhibition of Prolactin Secretion

Novelli, Antonello; Ganzetti, Ilaria; Müller, Eugenio E.

doi:10.1159/000212655

Cited by 6 publications

(6 citation statements)

References 15 publications

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“…It is of note that, similarly to the old women of this study, Nom decreased baseline prolactin levels in old female rats not differently than in young rats (Cocchi et al, 1984), an apparent paradox in view of the generally recognized defective TIDA function present in old rats (see above). The most likely interpretation of these, otherwise unexplicable, findings, was that old female rats, due to their defective TIDA function, develop denervation supersensitivity of the pituitary lactotropes e.g.…”

Section: Discussionsupporting

confidence: 38%

“…The most likely interpretation of these, otherwise unexplicable, findings, was that old female rats, due to their defective TIDA function, develop denervation supersensitivity of the pituitary lactotropes e.g. pituitary hyperresponsiveness to DA-mediated stimuli, Consistent with this proposition was the finding that bromocriptine, a direct DA agonist, lowered plasma prolactin in old rats at doses which were ineffective in normal cycling rats (Cocchi et aL, 1984).…”

Section: Discussionmentioning

confidence: 94%

“…Hence, it has been hypothesized (Meites, 1982) that the defective DA inhibition on pituitary lactotrophs may contribute to the occurrence of hyperprolactinemia and the development of prolactinomas, so frequently encountered in old female rats (Sarkar et al, 1982;Cocchi et al, 1984).…”

Section: Discussionmentioning

confidence: 99%

“…Whatever its true interpretation may be, the slight increase in baseline prolactin of the aged women by no means is comparable to the highly elevated prolactin levels, often associated to prolactinomas, of aged female rats (Sarkar eta[., 1982;Cocchi et aL, 1984).…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of hypothalamic dopaminergic function by neuropharmacologic means in aged women

Castoldi¹,

Locatelli²,

Novelli³

et al. 1985

J. Neural Transmission

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The function of the hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons involved in the control of prolactin secretion was investigated in aged subjects with the use of nomifensine, an indirect-acting dopamine (DA) agonist, domperidone, a DA receptor antagonist, and DA, which acts directly on the pituitary lactotropes. In all 33 women, aged 69-92 yr, were studied. Baseline prolactin values were slightly but significantly higher in aged women (13 +/- 1.2 ng/ml, M +/- S.E.M.) than in a group of control fertile women (8 +/- 0.7 ng/ml). Oral administration of nomifensine (200 mg), in 14 aged women suppressed plasma prolactin (greater than or equal to 30% of baseline) in 8 subjects, a proportion not different from that present in fertile women (7/15) also receiving a single oral dose of nomifensine. Intravenous infusion of DA (0.04 microgram/kg min, 120 min) induced a similar inhibition in plasma prolactin in the aged and the fertile women, while administration of domperidone (4 mg i.v.) evoked a higher plasma prolactin rise, 15 min post-administration, in fertile than aged women. In all, presence of baseline prolactin levels only slightly elevated and prolactin responsiveness to nomifensine and DA not different from that of fertile women denote preservation of TIDA neuronal function in old women. The blunted response to domperidone of the old women is likely attibutable to a reduced pituitary pool of prolactin.

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Section: Discussionsupporting

confidence: 38%

Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of hypothalamic dopaminergic function by neuropharmacologic means in aged women

Castoldi¹,

Locatelli²,

Novelli³

et al. 1985

J. Neural Transmission

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“…Bromocriptine binds to D2 receptors on lactotrophs to inhibit PRL synthesis and release from the anterior pituitary (Israel et al, 1985). At 0.1 mg/kg, bromocriptine reduces serum PRL selectively in older female rats, but is ineffective in younger females (Cocchi et al, 1984). At 3.0 mg/kg, bromocriptine decreases serum PRL in male and female rats within 30 min of injection (Atterwill et al, 1989).…”

Section: Methodsmentioning

confidence: 99%

Prosocial effects of prolactin in male rats: Social recognition, social approach and social learning

Donhoffner

Saleh

Schink

et al. 2017

Hormones and Behavior

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Prolactin (PRL) and oxytocin (OT) are pituitary hormones essential for lactation, but also promote sexual behavior. OT stimulates social behaviors, such as recognition, approach, and learning, but less is known about PRL in these behaviors. Since PRL and OT have complementary functions in reproduction, we hypothesized that PRL increases social recognition, approach, and learning. Male Long-Evans rats received ovine PRL (oPRL; 0.5, 2.0 or 5.0 mg/kg), the PRL antagonist bromocriptine (0.1, 3.0 or 5.0 mg/kg) or saline 20 mins before testing for recognition of familiar vs. unfamiliar stimulus males. Saline controls preferred the unfamiliar male (p<0.05), while bromocriptine blocked this preference. oPRL did not increase preference. To measure social approach, we determined if PRL restores approach 2 hours after defeat by an aggressive male. Defeated rats avoided the aggressive male. 2 mg/kg oPRL, before or after defeat, restored approach towards the aggressive male (p<0.05). In non-defeated rats, oPRL or 3 mg/kg bromocriptine had no effect. To determine if PRL increases social learning, we tested social transmission of food preference. Rats choose between two unfamiliar flavors, one of which they have previously been exposed to through interaction with a demonstrator rat. Vehicle controls preferred chow with the demonstrated flavor over the novel flavor. oPRL-treated rats were similar. Bromocriptine-treated rats failed to show a preference. When tested one week later, only oPRL-treated rats preferred the demonstrated flavor. The results suggest that PRL is required for social recognition and learning, and that increasing PRL enhances social memory and approach, similar to OT.

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The neuroendocrine approach to psychiatric disorders: A critical appraisal

Müller

1990

J. Neural Transmission

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Tremendous efforts have been made to exploit the strategy of measuring the secretion of hormones into the plasma by the pituitary as a "window to the brain" and therefore as an insight into potential neurotransmitter receptor lesions in patients with psychiatric disorders. This contribution focuses upon the advantages and drawbacks of the neuroendocrine approach, caution and objectiveness necessary for the critical evaluation and interpretations of the data. Factors related to the neurobiology of the medial basal hypothalamus and its peculiar features, the information that can be derived from the administration of a specific neuroregulatory hormone or a neuroactive compound and evaluation of the evoked hormone release, the multiple constraints related to the drug itself and/or the physiology or coexisting pathology of the psychiatric patient under examination, are thoroughly discussed.

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In vivo Supersensitivity of the Anterior Pituitary of Old Female Rats to Dopaminergic Inhibition of Prolactin Secretion

Cited by 6 publications

References 15 publications

Evaluation of hypothalamic dopaminergic function by neuropharmacologic means in aged women

Evaluation of hypothalamic dopaminergic function by neuropharmacologic means in aged women

Prosocial effects of prolactin in male rats: Social recognition, social approach and social learning

The neuroendocrine approach to psychiatric disorders: A critical appraisal

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