DISTRIBUTION OF RADIOACTIVITY IN THE ORGANS OF THE RAT AND MOUSE AFTER INJECTION OF l-[3H]PROLYL-l-LEUCYL-GLYCINAMIDE

Abstract

SUMMARY The distribution of radioactivity after intrajugular injection of l-[3H]prolyl-l-leucyl-glycinamide has been studied by whole-body autoradiography in the mouse and by direct measurement of radioactivity in individual organs of the rat. There is good agreement between results obtained with the two techniques and animal species. High levels of radioactivity were found in the pineal gland, anterior pituitary, posterior (including intermediate) lobe of the pituitary, and epididymal and brown fat. Lower uptake of radioactivity occurred in the submaxillary gland, kidney, and adrenal gland. The preferential uptake of radioactivity by the pineal gland after injection of the labelled tripeptide suggests a role for this hypothalamic hormone in the control of pineal activity.