Biomaterial Database

Thyroid status influences rat serum but not brain TRH pyroglutamyl aminopeptidase activities. 1987

C H Emerson, and C F Wu

Serum and brain cytosol contains pyroglutamyl aminopeptidase activity that converts TRH to His-ProNH2 (TRH PAPase). Whereas serum TRH PAPase has specificity for TRH, this is not the case for brain cytosol PAPase. Recent reports indicate that a brain membrane fraction contains TRH PAPase that is specific for TRH and has a remarkable similarity to serum TRH PAPase. In the present studies, a method for measuring serum TRH PAPase activity and the activities of the membrane and cytosol brain TRH PAPase enzymes are described. The effect of thyroid status on these different TRH PAPase activities was determined. In hypothyroid rats serum TRH PAPase activity was decreased, whereas in rats treated with supraphysiological doses of T4 it was increased. In contrast, the cytosolic and the membrane TRH PAPase enzymes in brain were not affected by thyroid status. It is concluded that the membrane-associated brain TRH PAPase differs from the serum TRH PAPase in terms of its response to thyroid hormone. In addition, the previously reported effects of thyroid status on rat serum TRH degrading activity are explained by the finding that thyroid hormone increases serum TRH PAPase activity.

UI	MeSH Term	Description	Entries
D006980	Hyperthyroidism	Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.	Hyperthyroid,Primary Hyperthyroidism,Hyperthyroidism, Primary,Hyperthyroids
D007037	Hypothyroidism	A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA. It may be primary or secondary due to other pituitary disease, or hypothalamic dysfunction.	Central Hypothyroidism,Primary Hypothyroidism,Secondary Hypothyroidism,TSH Deficiency,Thyroid-Stimulating Hormone Deficiency,Central Hypothyroidisms,Deficiency, TSH,Deficiency, Thyroid-Stimulating Hormone,Hormone Deficiency, Thyroid-Stimulating,Hypothyroidism, Central,Hypothyroidism, Primary,Hypothyroidism, Secondary,Hypothyroidisms,Primary Hypothyroidisms,Secondary Hypothyroidisms,TSH Deficiencies,Thyroid Stimulating Hormone Deficiency,Thyroid-Stimulating Hormone Deficiencies
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D011751	Pyroglutamyl-Peptidase I	An enzyme that catalyzes the release of a N-terminal pyroglutamyl group from a polypeptide provided the next residue is not proline. It is inhibited by thiol-blocking reagents and occurs in mammalian tissues, microorganisms, and plants. (From Enzyme Nomenclature, 1992) EC 3.4.19.3.	5-Oxoprolyl-Peptidase,Pyroglutamate Aminopeptidase,Pyrrolidonecarboxylate Peptidase,Pyrrolidonyl Peptidase,Pyroglutamyl-Peptide Hydrolase,5 Oxoprolyl Peptidase,Aminopeptidase, Pyroglutamate,Peptidase, Pyrrolidonecarboxylate,Peptidase, Pyrrolidonyl,Pyroglutamyl Peptidase I,Pyroglutamyl Peptide Hydrolase
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
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
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D000626	Aminopeptidases	A subclass of EXOPEPTIDASES that act on the free N terminus end of a polypeptide liberating a single amino acid residue. EC 3.4.11.	Aminopeptidase