| Abstract: | Selected synthetic luteinizing hormone releasing hormone preparations were assayed, and their potencies were determined relative to one sample utilizing primary cultures of enzymatically dispersed rat anterior pituitary cells. Preliminary cell culture experiments indicated that luteinizing hormone releasing hormone had to be in constant contact with cells for continued luteinizing hormone secretion. Luteinizing hormone levels in media reached a maximum concentration after 4 hr of continuous luteinizing hormone releasing hormone exposure. Cell culture bioassay was selected over the bioassay employing chronically ovariectomized steroid-blocked rats due to greater sensitivity and economy. The assay of each luteinizing hormone releasing hormone preparation was replicated four to seven times. Preparations from several companies were less potent (p less than 0.05) than the reference product. Contaminants were disclosed by TLC in preparations with potencies lower than the reference product. |
