Regulation versus modulation in GnRH receptor function

Journal Article · Fri Mar 01 00:00:00 EST 1985 · Am. J. Med. Sci.; (United States)

DOI:https://doi.org/10.1097/00000441-198503000-00001· OSTI ID:5666213

Zolman, J C; Theodoropoulos, T J

Serum luteinizing hormone (LH) concentration after exposure to gonadotropin-releasing hormone (GnRH) indicates that an instantaneous increase occurs in the rate of release of LH directly from the anterior pituitary, as measured dynamically during superfusion in vitro. On the other hand, estradiol-17 beta (E2) alone shows no such instantaneous effect on LH release rate (at least for the first four hours), in either physiologic or pharmacologic concentrations. At the same time, brief (ten to 30 minute) exposure of isolated anterior pituitary plasma membranes to physiologic concentrations of E2 significantly alters the binding of a fully biologically active /sup 125/I-GnRH to its plasma membrane receptor protein. In order to characterize the effect of E2 on GnRH binding further, dispersed bovine anterior pituitary cells were preincubated for six hours in the presence or absence of physiologic concentrations of E2 (10(-10)M). Following preincubation in the presence of E2, the cell suspension was incubated for 30 minutes with physiologic concentrations (5 x 10(-11) - 5 x 10(-10)M) of a fully biologically active /sup 125/I-GnRH. The treatment, at least, doubled the number of biologically important high affinity GnRH binding sites (Kd's . 7.5 x -10(-11) - 4.5 x 10(-10)M), and changed the binding capacity of some of the binding sites up to three fold, which altered the cooperativity of GnRH-receptor interaction. Thus, the interaction of E2 with GnRH at the level of GnRH receptor is mandatory for the short-term pituitary effect of E2 on LH release in vitro and in vivo.

• Research Organization: Univ. of Texas Medical Branch, Galveston
• OSTI ID: 5666213
• Journal Information: Am. J. Med. Sci.; (United States), Vol. 289:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LH
BIOCHEMICAL REACTION KINETICS
ANIMAL CELLS
CATTLE
CHEMICAL BONDS
ESTRADIOL
IN VITRO
IODINE 125
PITUITARY GLAND
RECEPTORS
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
ESTRANES
ESTROGENS
GLANDS
GONADOTROPINS
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOISOTOPES
REACTION KINETICS
RUMINANTS
STEROID HORMONES
STEROIDS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques