The Origins and Significance of Pulsatility in Hormone Secretion from the Pituitary

In this review we first consider what information is carried by the activity of oxytocin cells. For these, as for many neuroendocrine neurones, synchronized bursting activity leading to pulsatile secretion is particularly important, and we consider possible mechanisms by which bursting may arise, and the role of intrinsic cell properties. Vasopressin cells also show a type of bursting behaviour, but their activity is not synchronized. We show how the behaviour of vasopressin cells fits a very simple dynamical systems model. Even structurally simple dynamical systems models can be computationally complex, with a rich repertoire of behaviour, and we show how the vasopressin cell model can be adapted and expanded to model the LHRH pulse generator network, and how the pituitary responsiveness to hypothalamic releasing factors may also be modelled with a different class of dynamical systems model.