Amino acid and putative neurotransmitter transport in human Y79 retinoblastoma cells. Effect of insulin and insulin-like growth factor

Mark A Yorek; Joyce A Dunlap; Barry H Ginsberg

doi:10.1016/S0021-9258(18)60915-9

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Amino acid and putative neurotransmitter transport in human Y79 retinoblastoma cells. Effect of insulin and insulin-like growth factor

Journal article

Open access

Peer reviewed

Amino acid and putative neurotransmitter transport in human Y79 retinoblastoma cells. Effect of insulin and insulin-like growth factor

Mark A Yorek, Joyce A Dunlap and Barry H Ginsberg

The Journal of biological chemistry, Vol.262(23), pp.10986-10993

08/15/1987

DOI: 10.1016/S0021-9258(18)60915-9

PMID: 2886501

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Abstract

The binding of insulin and insulin-like growth factor I (IGF-I) and their effect on amino acid and neurotransmitter transport was studied in cultured human Y79 retinoblastoma cells. Y79 cells possess specific receptors for both insulin and IGF-I. Insulin binding to Y79 cells is characterized by a curvilinear Scatchard plot suggesting a two-site or two-affinity binding system. In contrast, IGF-I binding has a linear plot indicative of a one-site, one-affinity binding system. The uptake of glycine, a putative neurotransmitter in the retina occurs by a specific transport system in Y79 cells, independent of the uptake of other neutral amino acids. The uptake of glycine was increased 25-50% by either insulin or IGF-I. The response to insulin or IGF-I on glycine uptake is gradual and concentration dependent. The accumulation of other amino acids and putative retinal neurotransmitters by Y79 cells was not significantly affected by insulin of IGF-I. In addition, the activity of Na+/K+-ATPase was not influenced. The analysis of high affinity glycine uptake indicates that insulin and IGF-I are stimulating glycine transport by increasing the V'max without significantly affecting the K'm. Further analysis suggests that insulin and IGF-I are causing a recruitment of additional glycine transporters at the cell surface or activating otherwise nonfunctional transporters by an unexplained mechanism. Because of the implication that glycine responds as a neuroactive amino acid in Y79 cells these studies suggest that insulin and IGF-I may influence neuroactivity in the human retina by regulating the transport of glycine.

Binding, Competitive

Cell Line

Insulin - pharmacology

Glycine - metabolism

Insulin-Like Growth Factor I - pharmacology

Humans

Neurotransmitter Agents - metabolism

Receptors, Somatomedin

Retinoblastoma - metabolism

Amino Acids - metabolism

Insulin - metabolism

Somatomedins - pharmacology

Eye Neoplasms - metabolism

Receptor, Insulin - metabolism

Biological Transport - drug effects

Insulin - analogs & derivatives

Kinetics

Insulin-Like Growth Factor I - metabolism

Hydrogen-Ion Concentration

Details

Title: Subtitle: Amino acid and putative neurotransmitter transport in human Y79 retinoblastoma cells. Effect of insulin and insulin-like growth factor
Creators: Mark A Yorek
Joyce A Dunlap
Barry H Ginsberg
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.262(23), pp.10986-10993
DOI: 10.1016/S0021-9258(18)60915-9
PMID: 2886501
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Grant note: AM25295 / NIADDK NIH HHS DK28516 / NIDDK NIH HHS
Language: English
Date published: 08/15/1987
Academic Unit: Fraternal Order of Eagles Diabetes Research Center; Endocrinology and Metabolism; Internal Medicine
Record Identifier: 9984094661702771

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