Developmental expression of the tissue insulin-like growth factor II/mannose 6-phosphate receptor in the rat. Measurement by quantitative immunoblotting

• Published in: The Journal of biological chemistry Vol. 264; no. 28; pp. 16733 - 16738
• Main Authors: SKLAR, M. M, KIESS, W, THOMAS, C. L, NISSLEY, S. P
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05-10-1989
• Subjects: Aging - metabolism; Animals; Biological and medical sciences; Embryonic and Fetal Development; Fetus - metabolism; Fundamental and applied biological sciences. Psychology; Gene expression; Hexosephosphates - metabolism; Immunoblotting; Insulin-Like Growth Factor II - metabolism; Mannosephosphates - metabolism; Molecular and cellular biology; Molecular genetics; Organ Specificity; Rats; Rats, Inbred Strains; Receptor, IGF Type 2; Receptors, Cell Surface - analysis; Receptors, Cell Surface - biosynthesis; Receptors, Somatomedin; Somatomedins - metabolism
• ISSN: 0021-9258; 1083-351X

We used quantitative immunoblotting to measure the total tissue insulin-like growth factor II/mannose 6-phosphate (IGF-II/Man-6-P)
receptor in the rat. Whole embryos (6-15 days of gestation) and tissues from 16- and 20-day-old fetal and 5-, 10-, 20-, and
40-day-old postnatal rats were placed in liquid nitrogen, extracted with 2% Triton X-100, and boiled in 2% sodium dodecyl
sulfate. The extracts were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis together with aliquots of
a highly purified rat IGF-II/Man-6-P receptor standard. The protein bands were transferred from the gel to nitrocellulose
sheets by electroelution. The nitrocellulose sheets were incubated with a specific IGF-II/Man-6-P receptor antiserum (3637).
The immunoblots were developed with 125I-protein A and an immunoperoxidase stain. Stained areas were cut from the immunoblots,
and radioactivity was measured in a gamma-counter. IGF-II/Man-6-P receptor levels were high in fetal tissues and in most tissues
declined dramatically in late gestation and/or in the early postnatal period. Concentrations in 16-day-old fetal tissues,
expressed as percent of total protein in the extract, were: heart, 1.7; placenta, 1.0; lung, 0.7; intestine, 0.7; muscle,
0.5; kidney, 0.5; liver, 0.3; and brain, 0.1. In whole embryos (6-15 days of gestation), the IGF-II/Man-6-P receptor ranged
between 0.1 and 0.4% of total protein in the extract. The IGF-II/Man-6-P receptor size varied within approximately 20 kDa
among different tissues and also varied with developmental age in the same tissue. We conclude that the IGF-II/Man-6-P receptor
is a major cellular protein in some fetal tissues and that the developmental pattern of receptor expression suggests that
the receptor plays an important role in fetal growth and development.