Improvement of MRI diagnostic accuracy in the study of the hypothalamic-pituitary region provides precise anatomic details. In pituitary dwarfism, MRI reveals severe sella/pituitary gland and stalk hypoplasia with or without posterior pituitary ectopia, and empty sella, and this more frequently in patients with multiple pituitary hormone deficiency. Two main hypotheses have been proposed to explain these findings: traumatic stalk transection during breech delivery, and abnormal embryonic development of the pituitary gland. The association between neuroradiological findings and type/severity of endocrine alteration has not yet been clarified. In diabetes insipidus, MRI findings are normal picture, posterior lobe not visible, and thickened stalk (as expression of preclinical/initial histocytosis). Patients with central precocious puberty or hypogonadotropic hypogonadism rarely show morphologic abnormalities (hamartoma of the tuber cinereum, partially empty sella). So far, MRI permits one to identify morphologic pictures in diseases previously considered ‘idiopathic’.

Research in neuroendocrinology faces particular challenges due to the complex interactions between cells in the hypothalamus, in the pituitary gland and in peripheral tissues. Within the hypothalamus alone, attempting to target a specific neuronal cell type can be problematic due to the heterogeneous nature and level of cellular diversity of hypothalamic nuclei. Because of the inherent complexity of the reproductive axis, the use of animal models and in vivo experiments are often a prerequisite in reproductive neuroendocrinology. The advent of targeted genetic modifications, particularly in mice, has opened new avenues of neuroendocrine research. Within this review, we evaluate various mouse models used in reproductive neuroendocrinology and discuss the different approaches to generate genetically modified mice, along with their inherent advantages and disadvantages. We also discuss a variety of versatile genetic tools with a focus on their potential use in reproductive neuroendocrinology.

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Prolactin response after domperidone (DOM) stimulus was used to investigate the functional status of the hypothalamo-hypophyseal axis in 57 congenital growth-hormone-deficient (GHD) children with and without magnetic resonance imaging (MRI) abnormalities. Response to DOM was significantly lower in the GHD children compared with controls, using maximum peak (p < 0.0001), increase (p < 0.0001) or percentage increase (p < 0.05). The lowest values were observed in patients with hypophyseal stalk transection. Thus, the DOM test revealed reduced dopaminergic transmission in GHD subjects, more severe in the transected group, in whom, however, a response to the stimulus was still present. Therefore, it seems that a residual hypothalamo-hypophyseal connection is preserved even if it is not detectable with MRI.