Biomaterial Database

Effects of urea, trimethylamine oxide, and osmolality on respiration and citrulline synthesis by isolated hepatic mitochondria from Squalus acanthias. 1986

P M Anderson

The effects of osmolality and of urea and trimethylamine oxide on citrulline synthesis and respiration by isolated hepatic mitochondria from Squalus acanthias (spiny dogfish) were determined. Optimal rates of citrulline synthesis and of respiration, as well as maximal respiratory control ratios, were obtained when the osmolality was about 300 mOsm when physiological concentrations of urea and trimethylamine oxide were present, analogous to mammalian mitochondria. Urea and trimethylamine oxide do not act as osmolytes and do not significantly affect these rates. When glutamate is not saturating, increasing concentrations of urea over the range of concentrations of physiological significance (e.g. 0.1-0.5 M) significantly inhibit citrulline synthesis, but not respiration. This response to urea concentration may reflect a specific homeostatic mechanism for maintaining physiological concentrations of urea.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008744	Methylamines	Derivatives of methylamine (the structural formula CH3NH2).
D008930	Mitochondria, Liver	Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)	Liver Mitochondria,Liver Mitochondrion,Mitochondrion, Liver
D009994	Osmolar Concentration	The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.	Ionic Strength,Osmolality,Osmolarity,Concentration, Osmolar,Concentrations, Osmolar,Ionic Strengths,Osmolalities,Osmolar Concentrations,Osmolarities,Strength, Ionic,Strengths, Ionic
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D002956	Citrulline
D004284	Dogfish	Sharks of the family Squalidae, also called dogfish sharks. They comprise at least eight genera and 44 species. Their LIVER is valued for its oil and its flesh is often made into fertilizer.	Squalidae,Dogfishes
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
D012754	Sharks	A group of elongate elasmobranchs. Sharks are mostly marine fish, with certain species large and voracious.	Shark
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol