Leptin access into the brain: a saturated transport mechanism in obesity.

In spite of extensive research in the last few years, we still do not have a clear understanding of how does leptin access its targets in the brain, and whether there is postreceptor defect in the brain of obese individuals. Recent data have shown that leptin is produced in the pituitary, where its receptor is also present. A better understanding of how leptin reaches the brain and how it modulates the release of hypothalamic neuropeptides and pituitary hormones is needed. This information is crucial in order to better understand the role that leptin may play in the pathophysiology of diseases, such as obesity, delayed puberty, or growth defects.