The OVLT signals to the supraoptic nucleus and paraventricular nucleus, leading to the release of vasopressin from the posterior pituitary.

“the OVLT signals to an area called the supraoptic nucleus. [...] It also signals to the so-called paraventricular nucleus [...] and the consequence of that communication is that a particular hormone is eventually released from the posterior pituitary. [...] from the pituitary, there's a hormonal signal that's released called vasopressin. Vasopressin also goes by the name antidiuretic hormone”

“We all harbor small sets of neurons. We call these sets of neurons nuclei, meaning little clusters of neurons that sense the levels of salt in our brain and body. There are a couple brain regions that do this.”

“So let's say you ingest something very very salty. Let's say you ingest, you know, a big bag of I I confess I don't eat these very often, but I really like those kettle potato chips. And I don't have too much shame about that because I think I have a pretty healthy relationship to food and I enjoy them. And I understand that it will drive salt levels up in my bloodstream and that will cause me to be thirsty. But why? Why? Because neurons in the OVLT come in two main varieties. One variety senses the osmalerity of the blood. And when the osmalerity, meaning the salt concentration in the blood is high, it activates these specific neurons in the OVLT. And by activates, I mean it causes them to send electrical potentials, literally send electrical signals to other brain areas. And those other brain areas inspire a number of different downstream events. The consequence of th that communication is that a particular hormone is eventually released from the posterior pituitary. So from the pituitary there's a hormonal signal that's released called vasop prein. Vasop prein also goes by the name antidiuretic hormone.”

“And the OVLT can send signals to other brain areas and then those other brain areas can do things like release hormones that can go and act on tissues in what we call the periphery in the body for instance have the kidneys secrete eat more urine to get rid of salt that's excessive salt in the body.”