Hypothalamic-pituitary-adrenal axis up-regulation in rats submitted to pituitary stalk compression.
J Endocrinol
; 180(2): 297-302, 2004 Feb.
Article
em En
| MEDLINE
| ID: mdl-14765982
ABSTRACT
The present study investigated the hypothalamic-pituitary-adrenal (HPA) axis activity in response to stress in adult male rats submitted to pituitary stalk compression (PSC) or sham operation. Animals received water or oral salt loading (2% NaCl) for one or eight days before the day of the experiment. On the 14th day post-surgery rats were killed under basal conditions or after 15 min immobilization stress. In the PSC group urine output increased significantly and plasma vasopressin (AVP) levels failed to respond to osmotic stimuli. Short-term salt load induced a significant increase in AVP levels in the sham-operated group. The PSC group presented higher adrenocorticotrophin (ACTH) and corticosterone levels compared with sham-operated rats, both in water intake and salt load conditions. Immobilization stress induced a similar increase in plasma ACTH and corticosterone concentrations in sham-operated and PSC groups under water intake. However, long-term salt load blunted the ACTH and corticosterone responses to immobilization stress in sham-operated rats. PSC rats submitted to short- and long-term salt loading presented no changes in ACTH and corticosterone levels after immobilization. Immobilization stress caused neither AVP responses nor plasma osmolality changes in sham and PSC groups. There was no difference in median eminence AVP content among all groups. In conclusion, the high ACTH and corticosterone levels found in PSC rats under water intake and salt loading conditions suggest an up-regulation of the HPA axis, with a preserved adaptive mechanism to chronic stress.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hipófise
/
Estresse Fisiológico
/
Córtex Suprarrenal
/
Diabetes Insípido
/
Hipotálamo
Limite:
Animals
Idioma:
En
Revista:
J Endocrinol
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Brasil