Down regulation of melanin concentrating hormone in virally induced obesity

Obesity is a complex disease involving genetic components and environmental factors and probably associated with the dysregulation of central homeosta sis normally maintained by the hypothalamic neuroendocrine/neurotransmitter network. We previously reported that canine distemper virus (CDV), which i s closely related to human measles virus, can target hypothalamic nuclei, a nd lead to obesity syndrome in the late stages of infection. Here, using di fferential display PCR, we demonstrate specific down-regulation of melanin- concentrating hormone precursor mRNA (ppMCH) in infected-obese mice. Althou gh ppMCH was down-regulated in all infected mice during the acute stage of infection, this was only seen during the late stage of infection in infecte d-obese mice. In addition, ppMCH mRNA and protein expression in the lateral hypothalamus was decreased in the absence of neuronal death. These results show the importance of ppMCH in the establishment and maintenance of obesi ty and the involvement of a virus as an environmental factor. (C) 2001 Else vier Science Ireland Ltd. All rights reserved.