Luteinizing hormone-releasing hormone (LH-RH) neurons in cultures of fetal rat hypothalamus.

Hypothalamic fragments from 21-day-old fetal rats were cultured in Maximow double-coverslip assemblies for 1 to 2 months. Neurons containing LH-RH were demonstrated immunohistochemically using an antiserum to LH-RH (Dermody; 1:500--1:4,000). LH-RH was demonstrable only in neuronal perikarya (8--13 micrometer) and in small (less than 1 micrometer) round structures nearby, primarily in explants of the median eminence-arcuate nucleus region. Reactive neurons were not found in explants of the preoptic area and could not be demonstrated in fetal hypothalami at the time of explantation. The presence of mature-looking LH-RH containing neurons in these cultures suggests that this tissue culture system can be used for the study of hypothalamic development.