Transcapillary permeability and subendothelial distribution of endothelial and amniotic fluid insulin-like growth factor binding proteins in the rat heart

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Endocrinology; (USA)

DOI:https://doi.org/10.1210/endo-127-3-1078· OSTI ID:6530558

Bar, R S; Clemmons, D R; Boes, M; Busby, W H; Booth, B A; Dake, B L; Sandra, A ^[1]

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1. Veterans Administration Hospital, Iowa City, IA (USA)

Insulin-like growth factor (IGF) binding proteins (IGFBP) were purified from conditioned media of cultured bovine endothelial cells (ECBP) and from human amniotic fluid (IGFBP-1), and then labeled by radioiodination. 125I-ECBP and 125I-IGFBP-1 were perfused through isolated beating rat hearts for 1 and 5 min, and the hearts fixed and analyzed for 125I-BP content and distribution. One to 4% of the perfused 125I-ECBP and 125I-IGFBP-1 crossed the capillary boundary. The ECBPs predominantly localized as intact 125I-BP in connective tissue elements of the heart with less 125I-BP in cardiac muscle. The ratio of 125I-ECBP in connective tissue: muscle (normalized to percent vol of these compartments) was greater than or equal to 10:1. In contrast, the IGFBP-1 had a greater affinity for cardiac muscle with ratios of 125I-IGFBP-1 in connective tissue:muscle of approximately 1:2. When 125I-IGF-I, in the absence of any BPs, was perfused through the hearts approximately 3-5% left the microcirculation and was found in subendothelial tissues. 125I-IGF-I localized primarily to cardiac muscle with a distribution of connective tissue:cardiac muscle of about 1:3. The findings in the isolated perfused heart were confirmed in intact animals. After 125I-IGFBP-1 was injected into anesthetized rats and allowed to circulate for 5 min, substantial radioactivity was associated with the heart. As in the isolated heart, the IGFBP-1 preferentially localized to cardiac muscle with a connective tissue:cardiac muscle ratio of 1:3. We conclude that IGFBPs produced by endothelial cells and the IGFBP-1 contained in amniotic fluid can cross the capillary boundaries of the rat heart, and that the ECBPs preferentially localize in connective tissue elements of the myocardium, whereas IGFBP-1 predominantly localizes in cardiac muscle.

• OSTI ID: 6530558
• Journal Information: Endocrinology; (USA), Journal Name: Endocrinology; (USA) Vol. 127:3; ISSN ENDOA; ISSN 0013-7227
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL LOCALIZATION
BLOOD VESSELS
BODY
CAPILLARIES
CARDIOVASCULAR SYSTEM
CATTLE
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENDOTHELIUM
FRACTIONATION
HEART
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLING
MAMMALS
MAN
MEMBRANE TRANSPORT
MUSCLES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PERFUSED ORGANS
PERMEABILITY
PRIMATES
PROTEINS
RADIOISOTOPES
RATS
RODENTS
RUMINANTS
SEPARATION PROCESSES
TISSUES
VERTEBRATES