Synthesis and release of luteinizing hormone in vitro: manipulations of Ca2+ environment

Journal Article · Thu Aug 01 04:00:00 EDT 1985 · Am. J. Physiol.; (United States)

OSTI ID:5023822

Liu, T C; Jackson, G L

The authors determined if luteinizing hormone (LH) synthesis is Ca2+ dependent and coupled to LH release. They monitored LH synthesis when LH release was stimulated either by specific (gonadotropin-releasing hormone (GnRH)) or nonspecific stimuli (50 mM K+ and 2 or 20 microM Ca2+ ionophore A23187) and inhibited by Ca2+-reduced medium. LH synthesis was estimated by measuring incorporation of (/sup 3/H)glucosamine (glycosylation) and (/sup 14/C)alanine (translation) into total (cell and medium) immunoprecipitable LH by cultured rat anterior pituitary cells. Both GnRH (1 nM) and 50 mM K+ significantly stimulated LH release and glycosylation, but had no effect on LH translation. A23187 also stimulated LH release, but significantly depressed glycosylation of LH and total protein and (/sup 14/C)alanine uptake. Deletion of Ca2+ from the medium depressed both GnRH-induced LH release and glycosylation. Addition of 0.1 mM EGTA to Ca2+-free medium not only inhibited GnRH-induced release and glycosylation of LH but also uptake of precursors and glycosylation and translation of total protein. Thus, glycosylation and release of LH are Ca2+ dependent. Whether parallel changes in LH release and glycosylation reflect a cause and effect relationship remains to be determined.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 5023822
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States); ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ALKALI METALS
ALKALINE EARTH METAL COMPOUNDS
AMINES
ANIMALS
BIOLOGICAL EFFECTS
BIOSYNTHESIS
BODY
CALCIUM COMPOUNDS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
CHELATING AGENTS
EGTA
ELEMENTS
ENDOCRINE GLANDS
GLANDS
GLUCOSAMINE
GLYCOLS
GONADOTROPINS
HEXOSAMINES
HEXOSES
HORMONES
HYDROXY COMPOUNDS
IN VITRO
IONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LH
MAMMALS
METALS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY GLAND
PITUITARY HORMONES
POTASSIUM
PRECURSOR
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RATS
RODENTS
SACCHARIDES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES