Differential effects of pre-weaning stress on adrenocorticotrophin and prolactin response to novel stimuli in adult rats.
Emotional responsiveness is reduced in adult animals which have been exposed to stress during their first few weeks of life (1, 2). The stress of 'handling', daily removal of pups from their mother during the pre-weaning period, also leads to a reduced corticosterone response to novel stimuli in adult life (3). In rats, exposure to novel stimuli results in the concomitant release of prolactin (PRL) and corticosterone (4-6). Here we show that, in male rats handled daily during the pre-weaning period of life and tested in adult life for their hormonal responses to exposure to novel audio-visual stimuli, the consequent secretion of adrenocorticotrophin (ACTH) is attenuated, but that of PRL is not. Thus, pre-weaning handling results in permanent changes in a neural system specific to the control of ACTH secretion rather than affecting pathways common to neuroendocrine responses to emotional stimuli (7).
Hamamura
M
M
Department of Physiology, Jichi Medical School, Minamikawachi-machi, Tochigi, 329-04, Japan.
Onaka
T
T