Changes in rat melanin-concentrating hormone and dynorphin messenger ribonucleic acids induced by food deprivation.

Melanin-concentrating hormone (MCH) and dynorphin genes are expressed in two discrete neuron populations of the rat lateral hypothalamus. Their roles remain hypothetical in mammals. In order to analyse changes in MCH and dynorphin gene expression, a multiplex competitive semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was developed to assay their mRNAs. This technique was used to examine MCH and dynorphin mRNA content in 24-h and 48-h food-deprived rats compared to controls. A two-fold induction of dynorphin mRNA by 24 h, followed by a sharp decrease at 48 h were observed. A moderate increase in MCH mRNA content was noticed by 24 h; 48 h of fasting restored the control levels.