"Prolactin (PRL) is secreted from lactotrophs of the anterior pituitary gland of rats in a unique pattern in response to uterine cervical stimulation (CS) during mating. Surges of PRL secretion occur in response to relief from hypothalamic dopaminergic inhibition and stimulation by hypothalamic releasing neurohormones. In this study, we characterized the role of oxytocin (OT) in this system and the involvement of vasoactive intestinal polypeptide (VIP) from the suprachiasmatic nucleus (SCN) in controlling OT and PRL secretion of CS rats. ... OT measurements of serial blood samples obtained from ovariectomized (OVX) CS rats displayed a prominent increase at the time of the afternoon PRL peak. The injection of VIP antisense oligonucleotides into the SCN abolished the afternoon increase of OT and PRL in CS-OVX animals. These findings suggest that VIP from the SCN contributes to the regulation of OT and PRL secretion in CS rats. We propose that in CS rats the regulatory mechanism(s) for PRL secretion comprise coordinated action of neuroendocrine dopaminergic and OT cells, both governed by the daily rhythm of VIP-ergic output from the SCN. This hypothesis is illustrated with a mathematical model."
Model Type: Neuron or other electrically excitable cell
Cell Type(s): Pituitary cell
Transmitters: Dopamine; Peptides
Model Concept(s): Oscillations
Simulation Environment: XPP (web link to model)
References:
Egli M et al. (2006). Prolactin secretory rhythm of mated rats induced by a single injection of oxytocin. American journal of physiology. Endocrinology and metabolism. 290 [PubMed]
Bertram R, Egli M, Toporikova N, Freeman ME. (2006). A mathematical model for the mating-induced prolactin rhythm of female rats. American journal of physiology. Endocrinology and metabolism. 290 [PubMed]
Egli M, Bertram R, Sellix MT, Freeman ME. (2004). Rhythmic secretion of prolactin in rats: action of oxytocin coordinated by vasoactive intestinal polypeptide of suprachiasmatic nucleus origin. Endocrinology. 145 [PubMed]