The effect of surgical isolation of the hypothalamus on its luteinizing hormone-releasing hormone content.

The luteinizing hormone-releasing hormone (LHRH) content of the medical basal hypothalamus was determined by radioimmunoassay 10 days after the isolation of this region. Between 70 and 90% of the LHRH disappeared from the hypothalamus after the surgical procedure. Thus, it seems that most of the LHRH present in the medial basal hypothalamus arises from, or is controlled by, cells elsewhere in the brain.