Affinity chromatography: a tool in protein chemistry

An investigation has been made into the incorporation of [35S]methionine into protein in various dis- crete areas of the brain that are considered to be involved in neuroendocrine function.Marked changes in incorporation in the preoptic area were seen in the rat and mouse during puberty and in the rat during the oestrous cycle.Marked changes during the oestrous cycle were also seen in the median eminence and anterior pituitary concomitant with the surge of luteinizing-hormone secretion that occurs before ovulation.Further, a circadian rhythm in the incorporation of [35S]methionine into protein was observed in the rat, with the fluctuation in the male being almost 180°out of phase when compared with that of the female.