Final answer:
Increased blood levels of sodium signify a higher blood osmolarity, which triggers the release of antidiuretic hormone (ADH) from the posterior pituitary gland to regulate water excretion by the kidneys and maintain blood pressure.
Step-by-step explanation:
The secretion of antidiuretic hormone (ADH), also known as vasopressin, is primarily triggered by the osmolarity of blood plasma. ADH is produced in the hypothalamus and released from the posterior pituitary gland. Its main role is to regulate the amount of water excreted by the kidneys. When blood osmolarity increases, due to factors such as dehydration, the concentration of water in the blood decreases, prompting the hypothalamus to signal the release of ADH.
This hormone acts on the kidneys, making them more permeable to water by activating aquaporin channels in the collecting ducts, facilitating water reabsorption into the bloodstream. Consequently, urine volume is reduced, and blood osmolarity is lowered back towards normal. Increased blood levels of sodium are a potential signal for increased ADH release due to the contribution to blood osmolarity.
In summary, of the options provided (increased blood levels of protein, glucose, potassium, sodium), increased blood levels of sodium would stimulate the release of ADH from the posterior pituitary gland.