Actions like this create a kind of feedback loop which produces autonomous oscillation of the partners after initial perturbance. This means that the underlying mechanism accountable for PRL fluctuation in early pregnant or pseudopregnant rats could be based on the described feedback loop between hypothalamic DA neurons and pituitary lactotrophs (Bertram et al. 2006).Figure 3A, C, and E show the simulation of the PRL rhythm of early pregnant/pseudopregnant rats calculated by the mathematical model that comprises three equations ,for a analytical description of the model, see Egli et al. (2004). The actual experimental values measured in the animals are displayed in the second column of Fig. 3B, D, and F. In the model, oxytocin , which is
