The recent interest in numerous bilateral communications between the i
mmune and neuroendocrine systems has established a rapidly expanding f
ield of immunoendocrinology. Neurotransmitters and hormones appear to
control cells of the immune system and, likewise, lymphokines and mono
kines modulate the function of the neuroendocrine system. Although the
se interactions are not fully defined, it is already possible to disti
nguish some neuroendocrine-immune interrelationships in amphibians and
reptiles. Season-related changes and interactions between the immune
system with glucocorticoid, gonadal, thyroid, and nervous systems are
reviewed.