ABSTRACT
This chapter describes the observations in the fetal monkey brain that: there are two different types of mammalian luteinizing hormone-releasing hormone (mLHRH) neurons which have the same gene, but originate at two different developmental stages and probably at two different locations and migrate into different areas of the brain. In addition, the chicken luteinizing hormone-releasing hormone-II (cLHRH-II) form is present in the non-human primate brain. Migration of late LHRH neurons continues into late fetal development, although the basic distribution pattern is established as early as E52. The final distribution of LHRH neurons in the late fetal age is similar to that described for fetal, juvenile, and adult monkeys. The origin of early LHRH cells is unclear at this time. Although at E30 several neuroblastic cells, weakly stained with GF-6, are present along olfactory nerves, a large number of darkly stained early LHRH neurons with a mature appearance have already appeared in the area of the rostrolateral forebrain.
