Norepinephrine detection in the anterior pituitary of microwave irradiated rats.

Microwave irradiation has become an acceptable technique for assessing small quantities of neurochemical substances in the brain. These substances are acetylcholine, cyclic nucleotides, biogenic amines, enkephaline and r-aminobutylic acid (1-4). Rapid inactivation of brain enzymes by microwave irradiation prevents postmortem changes of tissue substances. Although it is known that brain biogenic amines play an important role in neuroendocrine regulation (5, 6), the nature of amines in pituitary secretion of hormones is unknown. Other workers have found that catecholamine levels were either low or undetectable in the anterior pituitary (7, 8). We now report a useful microwave irradiation technique which enables determination of catecholamines in the anterior pituitary as well as the hypo