Biomaterial Database

Pituitary receptors for corticotropin-releasing factor: no effect of vasopressin on binding or activation of adenylate cyclase. 1984

M C Holmes, and F A Antoni, and T Szentendrei

In this study we have characterized binding sites for ovine corticotropin-releasing factor (oCRF) in the rat anterior pituitary gland, and have investigated whether the site of interaction of vasopressin and oCRF is at the plasma membrane level. The binding 125I-oCRF to anterior pituitary membranes was shown to be dependent on temperature, pH and cation concentration. Magnesium was essential for the binding reaction to take place. Two binding sites of Kd 7.63 X 10(-10) and 3.39 X 10(-8) M were found. Activity of adenylate cyclase in the membrane preparation increased in the presence of oCRF. The activity of the enzyme as well as the binding of 125I-oCRF was found to be influenced by guanosine-5'-triphosphate. Several hypothalamic neurohormones, including vasopressin, failed to alter the binding of 125I-oCRF to anterior pituitary membranes. Moreover, vasopressin failed to influence the stimulation of adenylate cyclase activity induced by oCRF. Preincubation of anterior pituitary segments with oCRF desensitized the corticotropin (ACTH) response to oCRF and decreased the amount of 125I-oCRF bound to membranes prepared from similarly treated pituitaries. The ACTH response to vasopressin remained unchanged. Following a preincubation of anterior pituitary segments with vasopressin, oCRF stimulated ACTH secretion, as well as the binding of 125I-oCRF to pituitary membranes was normal, while the ACTH response to vasopressin was markedly reduced. These results show that separate receptors mediate the action of vasopressin and oCRF. Moreover, the ACTH response to vasopressin and oCRF may be modulated separately.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010903	Pituitary Gland, Anterior	The anterior glandular lobe of the pituitary gland, also known as the adenohypophysis. It secretes the ADENOHYPOPHYSEAL HORMONES that regulate vital functions such as GROWTH; METABOLISM; and REPRODUCTION.	Adenohypophysis,Anterior Lobe of Pituitary,Anterior Pituitary Gland,Lobus Anterior,Pars Distalis of Pituitary,Adenohypophyses,Anterior Pituitary Glands,Anterior, Lobus,Anteriors, Lobus,Lobus Anteriors,Pituitary Anterior Lobe,Pituitary Glands, Anterior,Pituitary Pars Distalis
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003346	Corticotropin-Releasing Hormone	A peptide of about 41 amino acids that stimulates the release of ADRENOCORTICOTROPIC HORMONE. CRH is synthesized by neurons in the PARAVENTRICULAR NUCLEUS of the HYPOTHALAMUS. After being released into the pituitary portal circulation, CRH stimulates the release of ACTH from the PITUITARY GLAND. CRH can also be synthesized in other tissues, such as PLACENTA; ADRENAL MEDULLA; and TESTIS.	ACTH-Releasing Hormone,CRF-41,Corticotropin-Releasing Factor,Corticotropin-Releasing Hormone-41,ACTH-Releasing Factor,CRF (ACTH),Corticoliberin,Corticotropin-Releasing Factor-41,ACTH Releasing Factor,ACTH Releasing Hormone,Corticotropin Releasing Factor,Corticotropin Releasing Factor 41,Corticotropin Releasing Hormone,Corticotropin Releasing Hormone 41
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D000324	Adrenocorticotropic Hormone	An anterior pituitary hormone that stimulates the ADRENAL CORTEX and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further tissue-specific processing, ACTH can yield ALPHA-MSH and corticotrophin-like intermediate lobe peptide (CLIP).	ACTH,Adrenocorticotropin,Corticotropin,1-39 ACTH,ACTH (1-39),Adrenocorticotrophic Hormone,Corticotrophin,Corticotrophin (1-39),Corticotropin (1-39),Hormone, Adrenocorticotrophic,Hormone, Adrenocorticotropic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia