Release of Luteinizing Hormone-Releasing Hormone from Enzymatically Dispersed Rat Hypothalamic Explants Is Pulsatile

This study was conducted to investigate 1) the utility of a cell perifusion system to examine questions dealing with the regulation of pulsatile LHRH release and 2) the necessity of cell-cell connections for communication between LHRH neurons and for coordination of LHRH release. To this end, cell perifusion of both hemihypothalamic tissue and enzymatically dispersed hypothalamic tissue isolated from adult male rats was performed. Periodic perfusate samples were collected and assayed to measure LHRH release. LHRH release from both hemihypothalami and dispersed hypothalamic tissue was clearly pulsatile, with comparable pulse frequencies and amplitudes. These results were interpreted to support the hypothesis that coordination of pulsatile LHRH release can be maintained in the absence of most cell-cell connections. This suggests a paracrine rather than a neural mechanism for the coordination of LHRH secretory events leading to the distinct signals we observe as pulses of LHRH in situ.