GnRH immunofluorescence intensity and distribution. A, Representative fluorescence micrographs through the median eminence are shown from rostral to caudal in a representative rat (young, vehicle treated). Similar results were seen for other ages and hormone treatments. GnRH fluorescence intensity is shown in pseudocolor (red, most intense; purple, least intense). The greatest GnRH immunofluorescence is found in the caudal median eminence. Scale bar, 500 μm. B, Quantitative analysis of GnRH immunofluorescence intensity through the median eminence was performed using MetaMorph software. Three sections were used per rat at the rostral, medial, and caudal levels of the median eminence (n = 8 rats per group). There was no significant effect of either age or hormone on GnRH fluorescence intensity. Cap, Portal capillary region; 3V, third ventricle.