Luteinizing hormone-releasing hormone in human pituitary blood

Luteinizing hormone (LH) and LH-releasing hormone (LHRH) were measured by radioimmunoassay in blood samples collected from the pituitary gland during transsphenoidal surgery in 19 patients. Detectable levels of LHRH were present in 12 patients. Wide fluctuations of LHRH were seen in sequential samples collected at 10-minute intervals, suggesting a pulsatile mode of release. This technique may yield useful data on hypothalamic control of pituitary secretion.