Daily behavioral manipulation increases the total immunoreactive serum neurophysin concentrations irrespective of the duration of water deprivation in rats.

The daily training of rats in a two-compartment test box is sufficient to involve an increase in the total immunoreactive serum neurophysin concentrations when compared to totally undisturbed controls. Furthermore, this training is capable of masking the differences in neurophysin concentrations usually seen in unmanipulated rats after different durations of water deprivation. To interpret these high neurophysin levels, we speculatively suggest the existence of hypothalamic compensatory biosynthetic mechanisms which would induce the formation and/or the release of neurophysin pools under stress. Additionally, we propose that some subnuclei of the paraventricular nuclei are the neuroanatomical substratum of these mechanisms.