Biomaterial Database

Thyrotropin-releasing hormone receptors in the pituitary of rainbow trout (Oncorhynchus mykiss). 1995

R S Schwartzentruber, and R J Omeljaniuk

Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada.

Binding parameters of radiolabeled pGlu-3-Me-His2-Pro-NH2 ([3H]MeTRH) to pituitary TRH receptors of rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus) were investigated. Washed pituitary membranes were incubated with [3H]MeTRH in the absence (B0) or presence of TRH or TRH analogs under various paradigms. Specific binding (Bsp) was thermolabile and tissue dependent. Association of Bsp was slow (k + 1 = 1.43 x 10(7) M-1 min-1) achieving equilibrium binding after 60 min, and remaining stable for at least 60 min. Thereafter, equilibrium-bound [3H]MeTRH was dissociated by addition of excess MeTRH; estimated dissociation rate constant (k - 1) and half-life (t1/2) were 6.74 x 10(-2) min-1 and 10.2 min, respectively, with a kinetically derived dissociation constant (k - 1/k + 1) of 4.71 x 10(-9) M. [3H]MeTRH binding was differentially displaced by TRH and TRH analogs. LIGAND analysis of multiple homologous (MeTRH) and heterologous (TRH) displacement experiments indicates the presence of a single class of binding sites with nanomolar affinity. Data pooled from multiple heterologous (TRH) displacement experiments suggested the presence of an additional class of higher-affinity (picomolar) binding sites. Additionally, examination of separate preparations of neurointermediate lobes and pars distalis from trout and goldfish suggested that these two classes of binding sites were differentially located between the two lobes. Specificity analysis of the trout pituitary TRH receptor indicates that the rank order of potency for [3H]MeTRH displacement was MeTRH > TRH > pGlu-Phe-Pro-NH2. Analogs with N- or C-terminal substitutions had little competitive potential. This study indicates the presence and binding characteristics of specific TRH receptors in the salmonid and cyprinid pituitary gland.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008566	Membranes	Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.	Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009419	Nerve Tissue Proteins		Proteins, Nerve Tissue,Tissue Proteins, Nerve
D010902	Pituitary Gland	A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM.	Hypophysis,Hypothalamus, Infundibular,Infundibular Stalk,Infundibular Stem,Infundibulum (Hypophysis),Infundibulum, Hypophyseal,Pituitary Stalk,Hypophyseal Infundibulum,Hypophyseal Stalk,Hypophysis Cerebri,Infundibulum,Cerebri, Hypophysis,Cerebrus, Hypophysis,Gland, Pituitary,Glands, Pituitary,Hypophyseal Stalks,Hypophyses,Hypophysis Cerebrus,Infundibular Hypothalamus,Infundibular Stalks,Infundibulums,Pituitary Glands,Pituitary Stalks,Stalk, Hypophyseal,Stalk, Infundibular,Stalks, Hypophyseal,Stalks, Infundibular
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011869	Radioligand Assay	Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders).	Protein-Binding Radioassay,Radioreceptor Assay,Assay, Radioligand,Assay, Radioreceptor,Assays, Radioligand,Assays, Radioreceptor,Protein Binding Radioassay,Protein-Binding Radioassays,Radioassay, Protein-Binding,Radioassays, Protein-Binding,Radioligand Assays,Radioreceptor Assays
D006054	Goldfish	Common name for Carassius auratus, a type of carp (CARPS).	Carassius auratus
D006207	Half-Life	The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.	Halflife,Half Life,Half-Lifes,Halflifes
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein