Growth hormone response to clonidine in adversely reared young adult primates: relationship to serial cerebrospinal fluid corticotropin-releasing factor concentrations

A reduction of the growth hormone (GH) response to the a, adrenergic agonis t clonidine is a neuroendocrine abnormality observed with reasonable consis tency among human patients with mood and anxiety disorders. In previous pri mate studies, in comparison to predictably reared controls, monkeys exposed as infants to maternal variable foraging demand (VFD) rearing exhibited pe rsistent elevations of cerebrospinal fluid (CSF) corticotropin-releasing fa ctor (CRF), as well as other biological disturbances. As CRF has been demon strated to inhibit GH release, the authors hypothesized that within VFD-rea red subjects, animals with relatively high CRF concentrations would exhibit relatively diminished GH responses to clonidine. The current study examine d the relationship between the GH response to clonidine in VFD-reared adult primates in relation to a range of both juvenile and follow-up CSF CRF con centrations. Nine bonnet macaques (Macaca radiata) were given ascending dos ages of clonidine under ketamine anesthesia. Plasma samples for GH-like imm unoreactivity were obtained throughout the session, A significant positive correlation was noted between juvenile CSF CRF concentrations and the level s of the neuropeptide observed in young adults. The mean of the serial CSF CRF concentrations exhibited a significant inverse relationship towards the GH response to clonidine in young adulthood, with relatively high CSF CRF associated with relatively attenuated CH responses to clonidine. These data raise the possibility that a reduced GH response to clonidine may inversel y reflect trait-like increases of central nervous system (CNS) CRF activity . (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.