The effect of sympathectomy upon iris tyrosinase activity. 1985

T Lloyd, and R L Kochel, and J M Weinstein

It is generally accepted that interruption of the sympathetic pathway to the eye may result in iris hypochromia in human infants. Weanling Dutch belted rabbits were used as a model system to investigate whether the melanin synthesizing enzyme, tyrosinase, is regulated in the iris of the juvenile animal by adrenergic innervation. Although we did not find a significant decrease in tyrosine activity isolated from the sympathetically denervated iris, we did observe a tenfold fall in iris tyrosine activity between the 30th and 120th days of life in both intact and denervated irides. About 90% of the iris tyrosine activity was localized in the pigmented epithelium and the remaining tyrosinase activity was found in the stromal tissue. This distribution of tyrosine activity was not affected by sympathetic denervation or time.

UI MeSH Term Description Entries
D007498 Iris The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
D010857 Pigment Epithelium of Eye The layer of pigment-containing epithelial cells in the RETINA; the CILIARY BODY; and the IRIS in the eye. Eye Pigment Epithelium
D011817 Rabbits A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes. Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D004156 Catechol Oxidase An enzyme of the oxidoreductase class that catalyzes the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. EC 1.10.3.1. Diphenol Oxidases,Diphenol Oxidase,Polyphenol Oxidase,Polyphenoloxidase,Oxidase, Catechol,Oxidase, Diphenol,Oxidase, Polyphenol,Oxidases, Diphenol
D000375 Aging The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time. Senescence,Aging, Biological,Biological Aging
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013562 Sympathectomy The removal or interruption of some part of the sympathetic nervous system for therapeutic or research purposes. Denervation, Sympathetic,Sympathetic Denervation,Denervations, Sympathetic,Sympathectomies,Sympathetic Denervations
D014442 Monophenol Monooxygenase An enzyme of the oxidoreductase class that catalyzes the reaction between L-tyrosine, L-dopa, and oxygen to yield L-dopa, dopaquinone, and water. It is a copper protein that acts also on catechols, catalyzing some of the same reactions as CATECHOL OXIDASE. EC 1.14.18.1. Dopa Oxidase,Phenoloxidase,Tyrosinase,Cresolase,Phenol Oxidase,Phenoloxidase A,Phenoloxidase B,Monooxygenase, Monophenol,Oxidase, Dopa,Oxidase, Phenol
D014443 Tyrosine A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin. L-Tyrosine,Tyrosine, L-isomer,para-Tyrosine,L Tyrosine,Tyrosine, L isomer,para Tyrosine

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