Role of the paraventricular and ventromedial hypothalamic nuclear areas in the regulation of the pituitary-adrenocortical system.
The role of the paraventricular (PVN) and ventromedial (VMN) hypothalamic nuclei in the activation and inhibition of the pituitary-adrenocortical system was studied in chronic experiments on rabbits. The functioning of the pituitary-adrenocortical system was estimated by changes in blood corticosteroid levels. PVN and VMN lesions resulted in a reduction of the stress-induced corticosteroid rise. VMN lesions resulted in smaller changes of the stress-induced response than PVN lesions while combined VMN and PVN lesions did not cause a larger reduction of the stress-induced activation than lesions of either area. The data obtained confirm that the PVN and VMN are connected in series. Hydrocortisone (100 micrograms/kg) administered intravenously 5 min before immobilization inhibits the stress-induced corticosteroid rise in intact rabbits. PVN and VMN lesions result in a reduction of the hydrocortisone inhibitory effect, PVN lesions having a greater effect than VMN ones. The PVN is of greater importance in both the activation and the inhibition of the pituitary-adrenocortical system than the VMN.
D000305:Adrenal Cortex Hormones / Q000097:blood* / Q000502:physiology; D000818:Animals; D006854:Hydrocortisone / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D013312:Stress, Physiological / Q000503:physiopathology; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology*
D000305:Adrenal Cortex Hormones; D006854:Hydrocortisone