In vitro regulation of LH biosynthesis and release by GnRH and estradiol

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7187967

Ramey, J W

Anterior pituitaries were taken from female rats at random stages of the estrous cycle, enzymatically dispersed, and cultured for 48h in steroid-free ..cap alpha..-modified Eagles medium followed by 24h in fresh medium +/- estradiol (E/sub 2/). The pituitary cells were then incubated in fresh medium containing radiolabeled precursors +/- gonadotropin releasing hormone (GnRH). Radioactive precursor incorporation into LH was determined by immuno-precipitation. The dose-dependent effects of E/sub 2/(10/sup -11/ to 10/sup -8/M) on /sup 3/H-glucosamine (/sup 3/H-Gln) and /sup 35/S-methionine (/sup 35/S-Met) incorporation into LH +/- 1 nM GnRH (4h) were investigated. GnRH (10/sup -9/M) and E/sub 2/ (all doses) significantly increased total /sup 3/H-Gln LH. Moreover, E/sub 2/ at 10/sup -9/M and 10/sup -8/M significantly enhanced GnRH stimulated LH glycosylation. In contrast, addition of GnRH and/or E/sub 2/ did not significantly increase /sup 35/S-Met incorporation into LH over a 4h period. The effects of various GnRH concentrations (10/sup -11/ to 10/sup -9/M; 8h) +/- E/sub 2/ (0.05 nM) on /sup 3/H-Gln LH and /sup 35/S-Met LH production were also investigated. In the absence of E/sub 2/, only 10/sup -9/M GnRH was effective in increasing total /sup 3/H-Gln LH and /sup 35/S-Met LH synthesis. However, in the presence of E/sub 2/, all concentrations of GnRH stimulated LH synthesis with /sup 3/H-Gln LH production responding in a dose related manner whereas /sup 35/S-Met LH production was maximally stimulated at all doses of GnRH. In the final series of experiments, pituitary cells previously exposed to estradiol were incubated for 4 h in normal calcium or low calcium medium containing /sup 3/H-Gln or /sup 35/S-Met +/- GnRH. Removal of extracellular calcium completely inhibited GnRH stimulated /sup 3/H-Gln LH and /sup 35/S-Met LH production.

• Research Organization: Cincinnati Univ., OH (USA)
• OSTI ID: 7187967
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
AMINES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOSYNTHESIS
BODY
CALCIUM
CARBOHYDRATES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELEMENTS
ENDOCRINE GLANDS
ESTRADIOL
ESTRANES
ESTROGENS
EVEN-ODD NUCLEI
GLANDS
GLUCOSAMINE
GONADOTROPINS
HEXOSAMINES
HEXOSES
HORMONES
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LH
LH-RH
LIBERINS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
METALS
METHIONINE
MONOSACCHARIDES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY GLAND
PITUITARY HORMONES
PRECURSOR
RADIOISOTOPES
RATS
RESPONSE MODIFYING FACTORS
RODENTS
SACCHARIDES
STEROID HORMONES
STEROIDS
SULFUR 35
SULFUR ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES