Regulation of luteinizing hormone (LH) subunit biosynthesis in cultured male anterior pituitary cells: effects of GnRH and testosterone

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

OSTI ID:5905035

Krummen, L A

The purpose of this study was to evaluate the direct effects of testosterone (T) on LH subunit apoprotein synthesis, glycosylation and release by the male pituitary. Cells from 1 wk castrate rats were cultured for 48 h in steroid-free medium followed by 48h in media /+-/10nM T. The cells were then incubated for 2, 4, 6, 8, or 12h in media containing (/sup 35/S)-methionine (/sup 35/S-Met) or (/sup 3/H)-glucosamine (/sup 3/H-Gln), /+-/1nM GnRH (exp 1) or in media containing precursors /+-/ 10nM T and/or 1nM GnRH (exp 2). Radiolabeled precursor incorporation into LH subunits was determined by immunoprecipitation followed by SDS-PAGE. In experiment 1, precursor incorporation into total protein (TP) and LH subunits increased linearly with time for at least 8h. GnRH did not effect precursor incorporation in to TP or /sup 35/S-Met labeling of LH subunits, but stimulated a linear, time-dependent accumulation of /sup 3/H-Gln into total LH subunits and the release of RIA-LH and radiolabeled subunits into media. Based on these results, the effects of T on LH subunit biosynthesis were studied during an 8h incubation. In experiment 2, GnRH enhanced the total /sup 3/H-Gln incorporation (but not /sup 35/S-Met incorporation) into both LH subunits. GnRH stimulated the release of /sup 35/S-Met LH..cap alpha.. and /sup 3/H-Gln LH subunits into media and increased the relative glycosylation of secreted LH subunits without altering the relative glycosylation of intracellular LH subunits. T inhibited RIA-LH release and incorporation of both precursors into total and secreted LH subunits (/+-/GnRH). However, only the relative glycosylation of secreted LH..cap alpha.. was reduced by T (/+-/GnRh).

• Research Organization: Cincinnati Univ., OH (USA)
• OSTI ID: 5905035
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
ANDROGENS
ANDROSTANES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
BODY
CARBOHYDRATES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTROPHORESIS
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GLANDS
GLUCOSAMINE
GONADOTROPINS
HEXOSAMINES
HEXOSES
HORMONES
HYDROXY COMPOUNDS
IMMUNOASSAY
IMMUNOLOGY
INHIBITION
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LABELLED COMPOUNDS
LH
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
METHIONINE
MONOSACCHARIDES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY GLAND
PITUITARY HORMONES
PRECURSOR
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
SACCHARIDES
STEROID HORMONES
STEROIDS
SULFUR 35
SULFUR ISOTOPES
SYNTHESIS
TESTOSTERONE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES