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Alterations in prolactin secretion during the 1st postnatal month following perinatal dopaminergic blockade with
Insights
Perinatal haloperidol exposure creates a critical period, altering prolactin (PRL) secretion long-term. This dopamine blockade impacts PRL production and release, especially in females.
Area of Science:
- Neuroendocrinology
- Developmental neuroscience
Background:
- Dopamine plays a crucial role in regulating prolactin (PRL) secretion.
- Perinatal exposure to neuroleptics may disrupt neurodevelopmental processes.
Purpose of the Study:
- To investigate the effects of perinatal haloperidol administration on postnatal prolactin secretion.
- To identify a critical developmental period where dopamine blockade causes lasting changes in PRL secretion.
Main Methods:
- Pregnant rats and newborn rats were administered haloperidol during specific perinatal periods.
- Pituitary and serum prolactin levels were measured weekly via radioimmunoassay throughout the first postnatal month.
- Radioimmunoassay (RIA) was used to quantify prolactin (PRL) levels.
Main Results:
- Prenatal haloperidol exposure significantly increased pituitary and serum prolactin (PRL) levels, particularly in females.
- Postnatal haloperidol administration resulted in a V-shaped PRL response, indicative of neuroleptic withdrawal.
- Data confirm a critical period for haloperidol-induced alterations in postnatal PRL production and secretion.
Conclusions:
- Perinatal haloperidol exposure establishes a critical window for long-term disruption of prolactin (PRL) regulation.
- Elevated pituitary PRL may result from altered synthesis or increased somatomammotroph differentiation.
- Serum PRL elevation suggests impaired release control, potentially due to tuberoinfundibular neuron damage from sustained prolactinemia.
Abstract:
This research was intended to study the effects of perinatal haloperidol administration on the postnatal secretion of prolactin (PRL) with the aim of investigating the existence of a 'critical period' during which the lack of dopamine influence could cause long-term alterations in the secretion of this hormone. A first group of animals, composed of pregnant rats, was injected daily with haloperidol (1 mg/kg) from day 16 of gestation to delivery. A second group of newborn rats received the same dose from days 2 to 6 after birth. Pituitary and serum PRL were measured weekly by radioimmunoassay during the 1st postnatal month in pups from the injected mothers, in postnatally injected rats, and in controls. The results showed a significant increase in the pituitary amounts of PRL that was more intense after the prenatal treatment, especially in the females. In serum, the prenatal treatment induced PRL levels higher than in the controls, whereas the postnatally injected group exhibited a V-shaped response which has been described as characteristic of neuroleptic withdrawal. These data confirm the existence of a 'critical period' during which perinatal administration of haloperidol alters the postnatal PRL production and secretion patterns. The persistence of high PRL contents in pituitary may reflect an alteration in the hormone synthesis and/or an increase in the rate of somatomammotrophes that differentiate into lactotrophes after suppression of dopamine influence. The high PRL levels in serum indicate a failure in the control of PRL release, perhaps after damaging the tuberoinfundibular neurons as a consequence of the high prolactinemia induced by the treatment.