Histochemistry of puberty. A multidisciplinary study in the rat.

A displacement of structures in the hypothalamic region of the rat has been reported in previous papers. 1 micron granules located in neuroblast like cells containing catalase activity (which were detected by enzyme histochemical methods) undergo a shift from the median eminence (at day 22 after birth) towards the ventromedial part of the hypothalamus (at day 35 after birth). This displacement terminates in the medio-basal part of the arcuate nucleus (at day 55 after birth). A similar displacement of dopaminergic fluorescent perikarya has been described following the same route, with the same time sequence. Neonatal application of monosodium glutamate (MSG) leads to an acceleration of the displacement of both the catecholaminergic and the catalase containing perikarya. However after day 25 (after birth) all fluorescent perikarya disappear whereas the catalase containing cell survive when they finally reach the arcuate area.