Utilization and synthesis of glutamine in the lens

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6180434

Jernigan, Jr, H M; Geller, A M

Previous studies with rat and calf lenses have shown that the primary source of lenticular glutamate for a wide variety of pathways is glutamine, which is more readily transported from the surrounding fluids than glutamate. In contrast, recent studies showed that monkey lenses utilize glutamate more rapidly than glutamine, although glutamine appears to enter monkey lenses more rapidly than glutamine. Further studies were initiated to elucidate the balance between transport, deamidation, and synthesis of glutamine in the lens. Glutamine synthesis in intact rat lenses was barely detectable; however, homogenates of adult rat lenses converted measurable amounts of (/sup 3/H)-glutamate to glutamine. The identity of the product was confirmed using glutaminase. Glutamine deamidation in intact rhesus monkey lenses incubated in TC-199 medium containing 2 mM glutamine was only 0.19 ..mu..mol g/sup -1/ hr/sup -1/, compared with 1.96 ..mu..mol g/sup -1/ hr/sup -1/ for rat lenses under identical conditions. However, under optimal assay conditions, glutaminase activity in monkey lens homogenates was similar to that of rat lens homogenates. Thus, the rate of synthesis and deamidation of glutamine by intact lenses is apparently limited factors other than total lenticular glutamine synthetase and glutaminase activity.

• Research Organization: Univ. of Tennessee, Memphis
• OSTI ID: 6180434
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMIDASES
AMIDES
AMINO ACIDS
ANIMALS
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
BODY
BODY AREAS
CARBOXYLIC ACIDS
CRYSTALLINE LENS
ENZYME ACTIVITY
ENZYMES
EYES
FACE
GLUTAMIC ACID
GLUTAMINE
HEAD
HOMOGENATES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
METABOLISM
MONKEYS
NON-PEPTIDE C-N HYDROLASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PRIMATES
RATS
RODENTS
SENSE ORGANS
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES