Cholesterol biosynthesis by the cornea. Comparison of rates of sterol synthesis with accumulation during early development

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Journal of Lipid Research; (USA)

OSTI ID:5189202

Cenedella, R J; Fleschner, C R ^[1]

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1. Kirksville College of Osteopathic Medicine, MO (USA)

The origin of the cholesterol needed by the cornea for growth and cell turnover was addressed by comparing absolute rates of sterol synthesis with rates of sterol accumulation during early development of the rabbit. Linearity of incorporation of {sup 3}H{sub 2}O and ({sup 14}C)mevalonate into digitonin-precipitable sterols with time of incubation in vitro and a lack of accumulation of {sup 14}C in intermediates of sterol biosynthesis indicated that tritiated water can validly be used to measure rates of sterol synthesis by the cornea. The rate of sterol synthesis per unit weight of rabbit cornea was constant between 14 and 60 days of age at an average 1.03 nmol of {sup 3}H of {sup 3}H{sub 2}O incorporated/mg dry cornea per 8 h. Essentially all of the synthesized cholesterol and most of the cholesterol mass was present in corneal epithelium. The cumulative sterol synthesized over the 46-day period studied exceeded the observed rate of cholesterol accumulation by sixfold. Cholesterol synthesized in excess of the growth requirement was likely used to support turnover of the epithelium which was estimated at 9 days. Removal of cholesterol from the cornea by excretion into tear fluid and clearance by high density lipoproteins are also considered.

• OSTI ID: 5189202
• Journal Information: Journal of Lipid Research; (USA), Vol. 30:7; ISSN 0022-2275
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHOLESTEROL
BIOSYNTHESIS
CORNEA
METABOLISM
CARBON 14 COMPOUNDS
CLEARANCE
IN VITRO
MEVALONIC ACID
RABBITS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
WATER
ANIMALS
BODY
BODY AREAS
CARBOXYLIC ACIDS
EYES
FACE
HEAD
HYDROGEN COMPOUNDS
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
SENSE ORGANS
STEROIDS
STEROLS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques