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Title: Parathyroid hormone blocks the stimulatory effect of insulin-like growth factor-I on collagen synthesis in cultured 21-day fetal rat calvariae

We examined the interaction of parathyroid hormone (PTH) and recombinant human insulin-like growth factor I (IGF-I) on collagen synthesis in 21-day fetal rat calvariae as assessed by measuring the incorporation of ({sup 3}H)proline into collagenase-digestible protein. After 96 hours of culture, 10 nM PTH antagonized the stimulation of collagen synthesis and partially blocked the increase in dry weight produced by 10 nM IGF-I. The effect of PTH to block IGF-I stimulated collagen synthesis was observed in the central bone of calvariae and was mimicked by forskolin and phorbol 12-myristate 13-acetate, but not by 1,25-dihydroxyvitamin D3, transforming growth factor-alpha or dexamethasone. Our data are consistent with the concept that the direct effect of PTH is to inhibit basal CDP labeling and fully oppose IGF-I stimulated CDP labeling. The finding that this effect of PTH is mimicked by forskolin and PMA suggests that this block in IGF-I stimulation of CDP labeling involves both cAMP and protein kinase C mediated pathways.
Authors:
; ;  [1]
  1. (Univ. of Connecticut Health Center, Farmington (USA))
Publication Date:
OSTI Identifier:
5803013
Resource Type:
Journal Article
Resource Relation:
Journal Name: Bone; (USA); Journal Volume: 11:6
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; COLLAGEN; BIOSYNTHESIS; GROWTH FACTORS; BIOCHEMICAL REACTION KINETICS; PARATHORMONE; PHORBOL ESTERS; BIOLOGICAL EFFECTS; AMP; BIOLOGICAL PATHWAYS; DEXAMETHASONE; FETUSES; PHOSPHOLIPIDS; PHOSPHOTRANSFERASES; PROLINE; RATS; SKULL; TRACER TECHNIQUES; TRITIUM COMPOUNDS; ADRENAL HORMONES; AMINES; AMINO ACIDS; ANIMALS; AZOLES; BODY; CARBOXYLIC ACIDS; CARCINOGENS; CORTICOSTEROIDS; ENZYMES; ESTERS; GLUCOCORTICOIDS; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; HORMONES; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; ISOTOPE APPLICATIONS; KETONES; KINETICS; LIPIDS; MAMMALS; MITOGENS; NUCLEOTIDES; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; ORGANS; PEPTIDE HORMONES; PHOSPHORUS-GROUP TRANSFERASES; PREGNANES; PROTEINS; PYRROLES; PYRROLIDINES; REACTION KINETICS; RODENTS; SCLEROPROTEINS; SKELETON; STEROIDS; SYNTHESIS; TRANSFERASES; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques; 560300 -- Chemicals Metabolism & Toxicology