Neonatal hyperthyroidism on rat heart: interrelation with nitric oxide and sex.

Purpose: To clarify the mechanism mediating the effect of hyperthyroidism on cardiac function during the second month of life in rats.

Methods: Male and female Sprague-Dawley rats were assigned to a control or to a triiodothyronine (T3)-treated group. Treatment of each group was started on the third day after birth.

Involvement of nitric oxide and caveolins in the age-associated functional and structural changes in a heart under osmotic stress.

Previous work done in our laboratory showed that water restriction during 24 and 72h induced changes in cardiovascular NOS activity without altering NOS protein levels in young and adult animals. These findings indicate that the involvement of NO in the regulatory mechanisms during dehydration depends on the magnitude of the water restriction and on age. Our aim was to study whether a controlled water restriction of 1 month affects cardiac function, NO synthase (NOS) activity and NOS, and cav-1 and -3 protein levels in rats during aging.