The brain is a gland of unity: the brain is one with the body. - Richard Bergland

Animal experiments have confirmed the necessity of delivering hormones into the ventricle: the powerful hormone endorphin does not change behaviour if it is given intravenously; vasopressin will improve memory in animals only if it given into the ventricles; insulin given through the bloodstream does not control appetite but it is the best hormone for such control if given into the brain; and bombesin... only stops stomach ulceration if given into the brain.

The ventricles of the human brain... are filled with hormones, and until the hormones swimming in these oceans are dredged out, countless millions of our fellows will remain with brain illnesses that can be neither understood nor treated. Many of their hormone-hungry brains may be fixed as easily as hormone-hungry bodies are fixed with thyroid hormone, insulin, oestrogen and testosterone, but that work cannot begin until cause and effect relationships between brain hormones and brain diseases have been established.

Molecules move not only from the brain to the endocrine system but also from the endocrine system, indeed, from all parts of the body to the brain.