Maternal separation during nursing alters basal neuroendocrine levels in juvenile and adult rats.
BACKGROUND
Work with different animal models including that of maternal separation during nursing has shown that early adverse experiences such as abuse, maternal abandonment and psychosocial stress may favor the development of various psychopathologies. However, several neuroendocrine changes have not been completely described yet.


OBJECTIVE
To establish whether maternal separation during nursing modifies the basal levels of neurohormones such as corticosterone, ACTH, oxytocin and vasopressin in juvenile and adult rats (aged 35 and 90 days, respectively).


METHODS
Wistar rats were separated from their mothers for two periods of 3 hours per day during the 21 days of nursing. Once these rats had reached 35 and then 90 days of age, blood samples were taken from both the separated and control groups to obtain serum for immunoenzymatic assays and measure the levels of each of the hormones.


RESULTS
Concentrations of corticosterone were higher in control adult females in comparison with the rest of the groups and lower in the control adult males. Those of ACTH were higher in the separated young males and females than in the adult groups. Oxytocin levels were significantly higher in the separated adult females in comparison with the other groups and significantly lower in the adult males. With respect to vasopressin, the separated groups had lower concentrations than the young and adult control groups.


CONCLUSIONS
These results show that the early stress to which rats were submitted produced changes in the basal responses of the hypothalamic-pituitary-adrenal axis, that these responses were distinct in males and females and that they also differed according to age.
Departamento de Ciencias Fisiológicas, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, D.C., Colombia. iriverosb@unal.edu.co.
Irene
I
Riveros-Barrera
Zulma
Z
Dueñas
D000324:Adrenocorticotropic Hormone / Q000097:blood* / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood* / Q000378:metabolism; D003345:Corticosterone / Q000097:blood* / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000097:blood* / Q000378:metabolism; D005260:Female; D007030:Hypothalamo-Hypophyseal System / Q000254:growth & development / Q000378:metabolism; D008297:Male; D008426:Maternal Deprivation; D010121:Oxytocin / Q000097:blood* / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000254:growth & development / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D001127:Arginine Vasopressin; D010121:Oxytocin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone
Breast feeding; arginine vasopressin; corticosterone; corticotropin-releasing hormone; mother-child relations; oxytocin; pituitary-adrenal system.