The Organ Specific Action of Thyroxin in Visual Pigment Differentiation

Development ◽  
1959 ◽  
Vol 7 (4) ◽  
pp. 556-563
Author(s):  
Fred H. Wilt
Keyword(s):  
Double Bond ◽  
Vitamin A ◽  
Visual Pigment ◽  
Rana Catesbeiana ◽  
Visual Pigments ◽  
Essential Difference ◽  
Phylogenetic Distribution ◽  
Chromophore Group ◽  
Vitamin A Metabolism ◽  
Organ Specific

In the course of his studies on the phylogenetic distribution of the retinal photopigments, Wald (1942, 1946, 1947) observed that the visual pigment of larvae of Rana catesbeiana changed from porphyropsin to rhodopsin during metamorphosis. The essential difference between the two visual pigments, which are conjugated proteins, is in the chromophore group, vitamin A aldehyde (or retinene). Vitamin A-2 aldehyde is the chromophore of porphyropsin; vitamin A-l aldehyde, which has one less double bond in its beta ionone ring, is the chromophore of rhodopsin (reviewed by Dartnall, 1958). The phenomenon of visual pigment conversion during metamorphosis has recently been examined in detail by Wilt (1959). His findings confirmed Wald's earlier report fully; furthermore, it was demonstrated that administration of thyroxin to premetamorphic animals stimulated photopigment conversion. Other evidence was presented supporting the hypothesis that thyroxin, or its physiologically active derivative, effects a change in vitamin A metabolism which results in a change in the type of chromophore on the visual protein.

The photoreceptors and visual pigments in the retina of the white sturgeon, Acipenser transmontanus

1990 ◽  
Vol 68 (7) ◽  
pp. 1544-1551 ◽  
Author(s):  
A. J. Sillman ◽  
M. D. Spanfelner ◽  
E. R. Loew
Keyword(s):  
Vitamin A ◽  
Visual Pigment ◽  
Visual Pigments ◽  
Spectrophotometric Analysis ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Light Regimen ◽  
Cone Pigment ◽  
Spectral Absorbance

The photoreceptors in the retina of the white sturgeon, Acipenser transmontanus (Chondrostei), were studied by means of scanning electron microscopy, in situ microspectrophotometry, and spectrophotometric analysis of visual pigment extracts. The white sturgeon retina is simple in that it contains only two morphologically distinct photoreceptors. The retina is dominated by rods with large outer segments, but there is a substantial population (40%) of single cones. Evidence was found for only one rod visual pigment and one cone visual pigment. Peak spectral absorbance (λmax) of the rod pigment is near 539 nm, whereas λmax of the cone pigment is near 605 nm. Both visual pigments are porphyropsin types with chromophores based on vitamin A2. No detectable rhodopsin based on vitamin A1 is ever present, regardless of season or light regimen. The results are discussed in terms of the sturgeon's behavior, as well as the implications for the evolution of color vision.

scholarly journals Utilization of retinoids in the bullfrog retina.

1982 ◽  
Vol 80 (6) ◽  
pp. 885-913 ◽  
Author(s):  
J I Perlman ◽  
B R Nodes ◽  
D R Pepperberg
Keyword(s):  
Vitamin A ◽  
Visual Pigment ◽  
Outer Segment ◽  
Rana Catesbeiana ◽  
Retinyl Palmitate ◽  
Visual Cycle ◽  
Trans Isomers ◽  
Isolated Retina ◽  
Cis Isomer

The capacity to generate 11-cis retinal from retinoids arising naturally in the eye was examined in the retina of the bullfrog, Rana catesbeiana. Retinoids, co-suspended with phosphatidylcholine, were applied topically to the photoreceptor surface of the isolated retina after substantial bleaching of the native visual pigment. The increase in photoreceptor sensitivity associated with the formation of rhodopsin, used as an assay for the appearance of 11-cis retinal in the receptors, was analyzed by extracellular measurement of the photoreceptor potential; in separate experiments using the isolated retina or receptor outer segment preparations, the formation of rhodopsin was measured spectrophotometrically. Treatments with the 11-cis isomers of retinal and retinol induced significant increases in both the rhodopsin content and photic sensitivity of previously bleached receptors. The all-trans isomers of retinyl palmitate, retinol, and retinal, as well as the 11-cis isomer of retinyl palmitate, were inactive by both the electrophysiological and spectrophotometric criteria for the generation of rhodopsin. Treatment with any one of the "inactive" retinoids did not abolish the capacity of subsequently applied 11-cis retinal or 11-cis retinol to promote the formation of rhodopsin. The data are discussed in relation to the interconversions of retinoids ("visual cycle of vitamin A") thought to mediate the regeneration of rhodopsin in vivo after extensive bleaching.

The visual pigments of wild white sturgeon (Acipenser transmontanus)

1995 ◽  
Vol 73 (4) ◽  
pp. 805-809 ◽  
Author(s):  
A. J. Sillman ◽  
M. E. Sorsky ◽  
E. R. Loew
Keyword(s):  
Vitamin A ◽  
Fresh Water ◽  
Visual Pigment ◽  
Visual Pigments ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Estuarine Water ◽  
Cone Pigments ◽  
Partial Bleaching

The visual pigments of the anadromous white sturgeon (Acipenser transmontanus) taken from relatively saline estuarine water were characterized by means of in situ microspectrophotometry and partial bleaching analysis of a digitonin extract. The three cone pigments (λmax = 605, 539, and ca. 460 nm) and one rod pigment (λmax = 541 nm) of the wild sturgeon are the same as those of cultured sturgeon that spend their entire lives in fresh water. All the visual pigments incorporate a chromophore based on vitamin A2. Unlike other anadromous fishes during the "saline phase," the white sturgeon shows no evidence of the presence of any vitamin A1 based visual pigment in the retina.

Vitamin A Metabolism in Infection

1955 ◽  
Vol 57 (2) ◽  
pp. 277-286 ◽  
Author(s):  
B. M. Kagan ◽  
Elizabeth Kaiser
Keyword(s):  
Vitamin A ◽  
Vitamin A Metabolism

Egg white peptide-based immunotherapy enhances vitamin A metabolism and induces RORγt+ regulatory T cells

2019 ◽  
Vol 52 ◽  
pp. 204-211 ◽  
Author(s):  
Daniel Lozano-Ojalvo ◽  
Mónica Martínez-Blanco ◽  
Leticia Pérez-Rodríguez ◽  
Elena Molina ◽  
Carmen Peláez ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Vitamin A ◽  
Egg White ◽  
Vitamin A Metabolism

Alterations in Vitamin A Metabolism During Zinc Deficiency and Food and Growth Restriction

1976 ◽  
Vol 106 (4) ◽  
pp. 569-574 ◽  
Author(s):  
J. Cecil Smith ◽  
Ellen D. Brown ◽  
E. G. McDaniel ◽  
Winnie Chan
Keyword(s):  
Vitamin A ◽  
Zinc Deficiency ◽  
Growth Restriction ◽  
Vitamin A Metabolism

The effect of cadmium on vitamin A metabolism

1978 ◽  
Vol 46 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Chieko Sugawara ◽  
Naoki Sugawara
Keyword(s):  
Vitamin A ◽  
Vitamin A Metabolism
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