[The response of hypothalamic CRF and AVP neurons of neonatal rats to simulated acute hypoxia].

AIM

To investigate the response of hypothalamic corticotropin releasing factor (CRF) and arginine vasopressin (AVP) of adrenalectomized neonatal rats to hypoxia.

METHODS

The hypoxia was simulated in hypobaric cabin. The amount of arginine vasopressin (AVP) and corticotropin releasing factor (CRF) was assayed by RIA method.

RESULTS

When neonatal rats exposed to acute hypoxia (simulated altitude of 5 000 m and 7 000 m, 24 h), their hypothalamic CRF was not changed in 3 d and 7 d rats, lower than control in 14 d, 21 d and 28 d rats, while hypothalamic AVP had no change in 3 d rats, was lower than control in 14 d and higher in 7 d, 21 d and 28 d rats. The responsive pattern of those two neuropeptides to acute hypoxia changed with the growth of rats. Adrenalectomy reduced the amount of hypothalamic CRF and AVP in 14 d, 21 d and 28 d rats, except AVP in 28 d rats. When adrenalectomized neonates exposed to hypoxia, there was no further change in CRF and AVE, means adrenalectomy not only removed the negative regulation of corticosteroid on CRF and AVE, but also inhibited the normal development of CRF and AVP neurons and thus, their responsive ability to hypoxia.