Cytidine metabolism in photoreceptor cells of the rat

نویسنده

  • S Y Schmidt
چکیده

During brief (30-min) incubations, isolated rat retinas accumulated [3H]cytidine, converted it to cytidine triphosphate (CTP), and incorporated it into RNA and cytidine diphosphate-diacylglyceride (CDG), a phospholipid precursor of phosphatidylinositol (Pl). Labeled CTP, RNA, and CDG contents were found to be two- to three-fold higher in photoreceptor cells than in cells of the inner retina. Autoradiograms showed that, within photoreceptor cells, silver grains representing RNA were concentrated over the nuclei in dark and light, while silver grains representing CDG were concentrated over the inner segments only after incubation in dark. The formation of labeled CTP and the synthesis of RNA were enhanced in light, while labeled CDG levels became reduced in light concurrent with an increase in the incorporation of labeled inositol into Pl. The 3H-labeled CDG content, however, was increased two- to fourfold in light in the presence of actinomycin D, and autoradiograms show a heavy concentration of silver grains over the inner segments of photoreceptor cells. These findings establish a role for cytidine nucleotides in photoreceptor cell metabolism and in light-dependent increases in RNA and Pl synthesis. Furthermore, the observations indicate that a competition may exist in light for cytidine or CTP and suggest that availability of cytidine for CDG synthesis may have a regulatory role in Pl metabolism within the photoreceptor cells.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Light- and cytidine-dependent phosphatidylinositol synthesis in photoreceptor cells of the rat

Incorporation of [3H]inositol into phosphatidylinositol (Pl) in isolated rat retinas is enhanced by light and by the addition of cytidine to the incubation media. In retinas preincubated with [3H]inositol in dark, [3H]inositol was chased into Pl in light by addition of unlabeled cytidine and was chased out of Pl in light by addition of unlabeled cytidine plus inositol. Autoradiograms of retinas...

متن کامل

Morphological changes in injured retinal pigment epithelium and photoreceptor cells after transplantation of stem cells into subretinal space

Introduction: Degenerative retinal diseases are main cause of irreversible blindness. Stem cells therapy is a promising way in these diseases. Therefore, mesenchymal stem cells because of its safety can produce degenerated cells and can play important role in treatment. The aim of this study was to examine morphological changes in injured retinal pigment epithelium (RPE) and photoreceptor cells...

متن کامل

Effect of let-7a overexpression on the differentiation of conjunctiva mesenchymal stem cells into photoreceptor-like cells

Objective(s): MicroRNAs (miRNAs) could regulate many cellular processes such as proliferation and differentiation. let-7a miRNA is one of the key regulators in the developmental transition of retinal progenitor cells into differentiated cells. Current evidence suggests that mesenchymal stem cells (MSCs) can isolate from various tissues such as bone marrow and conjuncti...

متن کامل

Morphology of retinal photoreceptor layer in continuous light-exposed and dark-adapted male cats

The morphology of retinal photoreceptor layer was studied in continuous light-exposed and dark-adapteddomestic male cats (Felis catus). The eyes of 12 healthy adult cats (4 in continuous light-exposed group, 4 in continuous dark-adapted group, and 4 in control group) were routinely fixed and studied by electron microscope. Results showed that the general structure of photoreceptor layer in this...

متن کامل

Identification and characterization of pigmented photoreceptor-producing microorganisms using FTIR spectroscopy

The identification, differentiation and classification of microorganisms have been subjects of research for many years. Recently, Fourier transform infrared (FTIR) spectroscopy techniques have gained attention in the characterization and classification of microorganisms based on biochemical profiles and cell structure characteristics. In the present study, the characterization and differentiati...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • The Journal of Cell Biology

دوره 97  شماره 

صفحات  -

تاریخ انتشار 1983