Insulin-like growth factor-I and insulin-like growth factor binding proteins in the bovine mammary gland: Receptors, endogenous secretion, and appearance in milk

Thesis/Dissertation · Fri Jan 01 04:00:00 UTC 1988

OSTI ID:7255475

Campbell, P G

This is the first study to characterize both insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) in bovine milk, to characterize the IGF-I receptor in the dry and lactating mammary gland, and to report de novo synthesis and secretion of IGF-I and IGFBP from normal mammary tissue. Immunoreactive IGF-I was principally associated with 45 kDa IGFBP in milk. Multiparous cows had a higher IGF-I concentration of 307 ng/ml than primiparous cows at 147 ng/ml. IGF-I concentration on day 56 of lactation was 34 ng/ml for combined parity groups. At parturition, IGF-I mass in blood and milk pools was 1.4 and 1.2 mg, respectively. Binding of {sup 125}I-IGF-I was specific for IGF-I with anIC{sub 50} of 2.2 ng which was a 10- and 1273-fold greater affinity than IGF-II and insulin, respectively. Association constants, as determined by Scatchard analysis, were similar for both pregnant and lactating cows at 3.5 and 4.0 L/nM, respectively. In addition, estimated mean receptor concentration was 0.25 and 0.23 pM/mg protein for pregnant and lactating cows, respectively. In a survey of mammary microscomes prepared from 48 cows, {sup 125}I-IGF-I binding declined with progressing lactation and a similar trend was observed during pregnancy.

• Research Organization: Pennsylvania State Univ., University Park, PA (USA)
• OSTI ID: 7255475
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BIOSYNTHESIS
BODY
BODY FLUIDS
CATTLE
CHEMICAL COMPOSITION
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
FOOD
GLANDS
GROWTH FACTORS
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LACTATION
MAMMALS
MAMMARY GLANDS
MATERIALS
MEMBRANE PROTEINS
MILK
MITOGENS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PREGNANCY
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RUMINANTS
SECRETION
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES