ABSTRACT
Cholecystokinin (CCK) is one of the most widely distributed and abundant peptides found in the brain, including particularly prominent localization in the cortex, hippocampus, midbrain and hypothalamus. The effects of CCK on several neuroendocrine systems have been studied: gonadotropins, neurohypophyseal hormones, prolactin, corticotropin releasing hormone, and ACTH. Initial studies employing intracerebroventricular injections of CCK showed no significant acute effects on plasma follicle stimulating hormone levels but a significant suppression of plasma luteinizing hormone levels. Given the extensive co-localization of CCK in oxytocinergic and vasopressinergic neurons, many of the initial studies of CCK’s effects on neuroendocrine secretion involved neurohypophyseal hormones. The effects produced by CCK administered peripherally must be differentiated from the effects produced by CCK administered centrally. Several studies have examined prolactin secretion in response to CCK administration. Clearly more work will be needed to unravel the exact role of central CCK in modulating lordosis behavior.
