Fertility depends upon timely ovulation, which is induced by a pituitary hormone, gonadotropin, the secretion of which is, in turn, controlled by a releasing hormone synthesized in the hypothalamus. The neurons which synthesize this releasing hormone, Luteinizing hormone relcasing hormone ?LHRH!, are dispersed as individual cells or small clusters of cells across a broad region of the base of the brain. Apparently diffuse, the positioning of these LHRH neurons may be exquisitely regulated to facilitate integration of multiple internal and external factors to synchronize secretion and optimize reproductive success. Previous experiments using computer-assisted visualization techniques indicate that this group of neurons is composed of diverse subgroups. Using specialized staining procedures, i.e. immunocytochemistry, together with automated computerized visualization techniques, Dr. King will examine the hypotheses that: ?1! activity is enhanced in a "core" subgroup of neurons in relation to the LH surge, using a marker protein ?c-fos! as an indicator metabolic/secretory activity; ?2! the pattern of neural input to the diverse subgroups of LHRH neurons differ, using tracing techniques and specialized staining techniques to identify the transmitters involved; and finally ?3! a "core" subgroup controls the activity of other subgroups. These studies will yield important insights into the mechanisms that control this critical system of neurons.
