Coupling of guanine nucleotide inhibitory protein to somatostatin receptors on pancreatic acinar membranes

Journal Article · Tue Sep 01 00:00:00 EDT 1987 · Am. J. Physiol.; (United States)

DOI:https://doi.org/10.1507/endocrine1927.63.8_978· OSTI ID:6863525

Sakamoto, C; Matozaki, T; Nagao, M; Baba, S

Guanine nucleotides and pertussis toxin were used to investigate whether somatostatin receptors interact with the guanine nucleotide inhibitory protein (NI) on pancreatic acinar membranes in the rat. Guanine nucleotides reduced /sup 125/I-(Tyr/sup 1/)somatostatin binding to acinar membranes up to 80%, with rank order of potency being 5'-guanylyl imidodiphosphate (Gpp(NH)p)>GTP>TDP>GMP. Scatchard analysis revealed that the decrease in somatostatin binding caused by Gpp(NH)p was due to the decrease in the maximum binding capacity without a significant change in the binding affinity. The inhibitory effect of Gpp(NH)p was partially abolished in the absence of Mg/sup 2 +/. When pancreatic acini were treated with 1 ..mu..g/ml pertussis toxin for 4 h, subsequent /sup 125/I-(Tyr/sup 1/)somatostatin binding to acinar membranes was reduced. Pertussis toxin treatment also abolished the inhibitory effect of somatostatin on vasoactive intestinal peptide-stimulated increase in cellular content of adenosine 3',5'-cyclic monophosphate (cAMP) in the acini. The present results suggest that 1) somatostatin probably functions in the pancreas to regulate adenylate cyclase enzyme system via Ni, 2) the extent of modification of Ni is correlated with the ability of somatostatin to inhibit cAMP accumulation in acini, and 3) guanine nucleotides also inhibit somatostatin binding to its receptor.

• Research Organization: Kobe Univ. School of Medicine (Japan)
• OSTI ID: 6863525
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 253:3; ISSN AJPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALI METAL COMPOUNDS
AMINES
AMINO ACIDS
AMP
ANTIGENS
AROMATICS
AUTORADIOGRAPHY
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMISTRY
CYCLASES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
GUANINE
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROXY ACIDS
HYDROXY COMPOUNDS
INORGANIC PHOSPHORS
INTERMEDIATE MASS NUCLEI
IODIDES
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LYASES
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PROTEINS
PURINES
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
SODIUM COMPOUNDS
SODIUM IODIDES
SOMATOSTATIN
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TYROSINE