[The effect of age and dehydration on the activity of the vasopressinergic system in rats].

The aim of our work was to study the different blood parameters as well as the activity of the vasopressinergic axis in young and mature male rats under normal conditions and following a 3-day dehydration cycle by water deprivation. Under normal conditions, our study demonstrates higher levels of vasopressin in mature rats as compared to young rats. This could be due in part to the higher blood osmolality in the mature rats. After dehydration, hypovolemia, plasmatic hyperosmolality, hypernatremia and hyperproteinemia cause a stimulation in vasopressin synthesis and release, as seen in results obtained from the hypothalamus, hypophysis and plasma in both young and mature rats. However, the response of the vasopressinergic axis to dehydration is greater in young rats, suggesting a more pronounced sensitivity to osmotic factors.