PMID- 1404083
OWN - NLM
STAT- MEDLINE
DCOM- 19921106
LR  - 20190724
IS  - 0022-4251 (Print)
IS  - 0022-4251 (Linking)
VI  - 95
IP  - 3
DP  - 1992 Aug
TI  - Stimulation of the release of [32P]guanosine 5'-diphosphate from G proteins in 
      the rat anterior pituitary lobe by gonadotrophin-releasing and 
      thyrotrophin-releasing hormones.
PG  - 669-77
AB  - Plasma membranes (1-2 mg protein) purified from the anterior pituitary lobes of 
      adult male rats were incubated with 0.6 mumol [alpha-32P]guanosine 
      5'-triphosphate (GTP) l-1 in an ATP-regenerating buffer at 37 degrees C for 60 
      min; during this incubation the [32P]GTP was hydrolysed and the nucleotide that 
      was predominantly bound to the membranes was [32P]GDP. The release of [32P]GDP 
      from the membranes was monitored at 37 degrees C; the amount released was 
      proportional to the protein concentration and increased as a function of time. 
      5'-Guanylylimidodiphosphate (Gpp(NH)p) increased [32P]GDP release by up to 30% at 
      0.1 mumol l-1. Although 10 nmol Gpp(NH)p l-1 had no effect on GDP release, it 
      appeared to stabilize the hormonal effect by blocking further GDP-GTP exchange. 
      Gonadotrophin-releasing hormone (GnRH) agonist and thyrotrophin-releasing hormone 
      (TRH), at 0.1 mumol l-1 caused a maximum increase in the release of [32P]GDP of 
      31-38%. The GnRH agonist (0.1 mumol l-1) stimulated GDP release by 21%, 24%, 17% 
      and 14% at 30 s, 1, 2 and 5 min, respectively. TRH (0.1 mumol l-1) stimulated GDP 
      release by 38%, 30%, 17% and 16% at 30 s, 1, 2 and 5 min, respectively. A GnRH 
      antagonist also stimulated [32P]GDP release, albeit less effectively than GnRH 
      agonist; the antagonist did not inhibit agonist stimulation of GDP release. These 
      results indicate that ligand binding to the GnRH and TRH receptors results in 
      interaction of the receptor with a guanine-nucleotide-dependent transducer 
      protein (G protein) and activation of GTP-GDP exchange.(ABSTRACT TRUNCATED AT 250 
      WORDS)
FAU - Ravindra, R
AU  - Ravindra R
AD  - Department of Medicine, East Carolina University, Greenville 27858-4354.
FAU - Aronstam, R S
AU  - Aronstam RS
LA  - eng
GR  - AA-07698/AA/NIAAA NIH HHS/United States
GR  - GM-37948/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - J Reprod Fertil
JT  - Journal of reproduction and fertility
JID - 0376367
RN  - 146-91-8 (Guanosine Diphosphate)
RN  - 33515-09-2 (Gonadotropin-Releasing Hormone)
RN  - 5Y5F15120W (Thyrotropin-Releasing Hormone)
RN  - EC 3.6.1.- (GTP-Binding Proteins)
SB  - IM
MH  - Animals
MH  - Cell Membrane/drug effects/metabolism
MH  - GTP-Binding Proteins/*metabolism
MH  - Gonadotropin-Releasing Hormone/*pharmacology
MH  - Guanosine Diphosphate/*biosynthesis
MH  - Male
MH  - Pituitary Gland, Anterior/cytology/drug effects/*metabolism
MH  - Rats
MH  - Rats, Wistar
MH  - Stimulation, Chemical
MH  - Thyrotropin-Releasing Hormone/*pharmacology
EDAT- 1992/08/01 00:00
MHDA- 1992/08/01 00:01
CRDT- 1992/08/01 00:00
PHST- 1992/08/01 00:00 [pubmed]
PHST- 1992/08/01 00:01 [medline]
PHST- 1992/08/01 00:00 [entrez]
AID - 10.1530/jrf.0.0950669 [doi]
PST - ppublish
SO  - J Reprod Fertil. 1992 Aug;95(3):669-77. doi: 10.1530/jrf.0.0950669.