Biomaterial Database

Further studies on the inactivation of thyrotrophin releasing hormone (TRH) by enzymes in the rat hypothalamus. 1980

E C Griffiths, and J A Kelly, and N White, and S L Jeffcoate

Thyrotrophin-releasing hormone (TRH) is known to be inactivated by enzymes present in the rat hypothalamus. To make a further study of the enzymes' action on the tripeptide, synthetic TRH was incubated with two hypothalamic subcellular fractions. By using a direct radioimmunoassay for TRH, the tripeptide was shown to be rapidly degraded by both supernatant and particulate fractions, with higher enzyme activity in the particulate fraction. Of several biologically-active peptides tested, only luteinizing hormone-releasing hormone was found to inhibit TRH inactivation; bacitracin, a polypeptide antibiotic, was also effective in inhibiting inactivation. Enzyme activity was highest in the middle hypothalamic area and lowest in the posterior hypothalamic area. Thin layer chromatography of the products of enzyme cleavage revealed the formation of only deamidated TRH in the supernatant fraction and the constitutent amino acids (pyroGlu, His, ProNH2) and histidylproline-diketopiperazine by the particular fraction, suggesting the presence of an amidase in the supernatant and two peptidases in the particulate fractions. These properties of the enzymes inactivating TRH may indicate that the enzymes could be of importance in regulating the endocrine and other functions attributed to this hypothalamic regulatory hormone.

UI	MeSH Term	Description	Entries
D007031	Hypothalamus	Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.	Lamina Terminalis,Preoptico-Hypothalamic Area,Area, Preoptico-Hypothalamic,Areas, Preoptico-Hypothalamic,Preoptico Hypothalamic Area,Preoptico-Hypothalamic Areas
D008297	Male		Males
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D003035	Cobalt	A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.	Cobalt-59,Cobalt 59
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D005290	Ferric Compounds	Inorganic or organic compounds containing trivalent iron.	Compounds, Ferric
D006728	Hormones	Chemical substances having a specific regulatory effect on the activity of a certain organ or organs. The term was originally applied to substances secreted by various ENDOCRINE GLANDS and transported in the bloodstream to the target organs. It is sometimes extended to include those substances that are not produced by the endocrine glands but that have similar effects.	Hormone,Hormone Receptor Agonists,Agonists, Hormone Receptor,Receptor Agonists, Hormone
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
D001414	Bacitracin	A complex of cyclic peptide antibiotics produced by the Tracy-I strain of Bacillus subtilis. The commercial preparation is a mixture of at least nine bacitracins with bacitracin A as the major constituent. It is used topically to treat open infections such as infected eczema and infected dermal ulcers. (From Goodman and Gilman, The Pharmacological Basis of Therapeutics, 8th ed, p1140)	Ak-Tracin,Altracin,Baci-IM,Baci-Rx,Baciguent,Bacitin,Bacitracin Zinc,Bacitracin Zinc Complex,Bacitracine Martinet,Ocu-Tracin,Topitracin,Zeba-Rx,Zinc Bacitracin,Ak Tracin,Baci IM,Baci Rx,Bacitracin, Zinc,Martinet, Bacitracine,Ocu Tracin,OcuTracin,Zeba Rx,Zinc, Bacitracin
D013347	Subcellular Fractions	Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)	Fraction, Subcellular,Fractions, Subcellular,Subcellular Fraction