EGF release by rat gonadotroph cells: characteristics and effects of LHRH

The ability of anterior pituitary cells of immature female rats to secrete epidermal growth factor (EGF) was studied using the reverse hemolytic plaque assay. An average of 22% of cells (22.12 +/- 0.49%) spontaneously released low amount of EGF, as measured by the small area of plaques surrounding cells (1230 +/- 67 micron2). To determine the cellular origin of EGF from the rat anterior pituitary gland, a combination of immunocytochemistry and reverse hemolytic plaque assay was used. Most of the EGF-secreting cells were identified as luteinizing hormone (LH) containing cells (72.14 +/- 2.97%). Treatment with luteinizing hormone releasing hormone (LHRH; 10 nM) significantly increased the plaque area formed around EGF-secreting cells (2438 +/- 114 micron2) without altering the number of EGF-secreting cells. These results indicate that EGF is mostly secreted by gonadotrophs and that this EGF release is enhanced by LHRH.