Abstract
The histo- and cytochemical localization of guanylate cyclase activity was examined in the newborn rat retina during the first three postnatal weeks. The reaction was first observed on the 3rd postnatal day on the apical plasmalemma of the retinal pigment epithelium. The reaction was seen on the disk and plasmalemma of the premature short outer segments from the 10th day. From the 14th day, the enzyme localization seemed to be the same as shown in the adult rat. The reaction products were restricted to the apical plasmalemma of the retinal pigment epithelium and disk and plasmalemma of the tip of the outer segments.
