Thyrotropin-releasing hormone: Inhibitory function on growth hormone through both somatostatin and growth hormone-releasing factor neurons

Double labelling immunohistochemistry using antibodies to thyrotropin releasing hormone (TRH) and somatostatin (SS) was undertaken in the anterior hypothalamus in 6 rats. Light microscopic quantitation revealed that 94.5% of SS immunopositive perikarya in the preoptic anterior hypothalamic area (POAHA) and 97.5% in the paraventricular nucleus appeared to be contacted by one or more TRH immunopositive terminals.