Neuroendocrine responses in neonatal mother-deprived rabbits.
To study both short- and long-term adaptation mechanisms activated by rabbits which were separated from their mothers (DLS) for 48 h between postnatal days 9 and 11, we examined plasma corticosterone concentrations before, during, and after DLS as well as the expression of glucocorticoid receptor (GR) in the hippocampus and the adrenal axis responses to a mild stress stimuli or exogenous ACTH injection. At postnatal day 10, plasma corticosterone concentration of DLS rabbits was similar to that of controls, but rose two-fold at day 11 (17.7 + or - 1.3 vs. 9.3 + or - 1.2 microg/dl, P<0.01) and then decreased at day 12, when suckling was allowed again, to match those of controls with no difference thereafter. At postnatal day 14, both control and DLS rabbits had similar basal corticosterone concentrations (2.2 + or - 0.4 vs. 2.3 + or - 1.1 microg/dl, respectively) as well as at day 120 (8.8 + or - 3.2 vs. 9.7 + or - 2.8 microg/dl, respectively). After the standardized stress stimulus, plasma corticosterone concentrations were lower in DLS rabbits than controls at postnatal days 14 (P<0.01) and 120 (P<0.05). At day 120, corticosterone levels rose similarly seven-fold (P<0.01) within 30 min after ACTH administration and remained sustained thereafter in both control and DLS rabbits. Positive immunoreactivity for GR was detected in the hippocampus and in the dorsal medial hypothalamic region at postnatal day 14. The present data suggest that 48 h DLS from postnatal days 9 to 11 results in a modified hypothalamic-pituitary-adrenal axis reactivity later in life.
Brecchia
Gabriele
G
Dipartimento di Scienze Biopatologiche ed Igiene delle produzioni animali e alimentari, Laboratorio di Biotecnologie fisiologiche, Sezione di Fisiologia veterinaria, Università di Perugia, Via S. Costanzo 4, I-06100 Perugia, Italy.
Bonanno
Adriana
A
Dall'Aglio
Cecilia
C
Mercati
Francesca
F
Zerani
Massimo
M
Di Grigoli
Antonino
A
Boiti
Cristiano
C
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D001835:Body Weight; D001921:Brain / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood*; D006624:Hippocampus / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System; D007031:Hypothalamus / Q000378:metabolism; D007150:Immunohistochemistry; D008426:Maternal Deprivation; D010913:Pituitary-Adrenal System / Q000378:metabolism; D011817:Rabbits; D011897:Random Allocation; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D013315:Stress, Psychological / Q000097:blood* / Q000378:metabolism*; D013997:Time Factors
D011965:Receptors, Glucocorticoid; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone