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D Rao

Publications and source records attributed to D Rao.

50 records · Page 3Linked to original sources
PubMed1989

Biosynthesis of estradiol-17 beta fatty acyl esters by microsomes derived from bovine liver and adrenals.

A fatty acyl coenzyme A:estradiol-17 beta acyl transferase activity has been detected in bovine hepatic and adrenocortical microsomes. It is thoroughly increased when adenosine triphosphate (5 mM) and coenzyme A (1 mM) are added to incubation buffer. Using a substrate concentration of 185 microM, the hepatic and adrenocortical microsomal activities have been found to be to 2.4 +/- 0.1 and 5.5 +/- 0.2 nmol/h/mg prot., respectively. Five major estradiol-17-esters have been isolated by reverse phase high performance liquid chromatography from both microsomal incubations, the fatty acid moieties being: arachidonate, linoleate, oleate, palmitate and stearate. However, the distribution of hepatic metabolites is quite different from that obtained with adrenocortical membranes, this is well explained by the corresponding differences between the endogenous contents of free fatty acids. With any of the two types of microsomal membranes used, the results show that estradiol is more susceptible to be esterified to polyunsaturated fatty acids than saturated ones. The possible physiological implications of such an activity in liver and adrenals are discussed.

Acylation↗
PubMed1987

Simple gas chromatographic method for the determination of medicagenic acid in alfalfa (Medicago sativa).

A gas chromatographic method for the determination of medicagenic acid in alfalfa leaves, stems, entire plant (tops) and roots and also in leaf protein concentrates is described. The method is based on extraction of lucerne saponins followed by hydrolysis of the triterpene glycosides. After derivatization of the liberated sapogenins to silylated products, the trimethylsilylated medicagenic acid was determined by gas chromatography. The sensitivity of the method permits the detection of 50 ng of medicagenic acid.

Chromatography, Gas↗
PubMed1987

Identification of the cooked food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and its N-acetylated and 3-N-demethylated metabolites in rat urine.

The extractable unconjugated metabolites of 2-amino-3-methylimidazo-[4,5-f]quinoline (IQ) were identified in the urine of rats which had received a single dose of [3H]IQ by gavage. The dichloromethane and ethylacetate extracts prepared from the alkalinized 0-24 h urines were analyzed by radio-TLC and radio-HPLC. The 3 major HPLC fractions were submitted to DCI-MS analysis. Unchanged IQ, N-acetylIQ and 3-N-demethylIQ have been identified. Extractable unconjugated metabolites represent only about 0.85% of the total radioactivity excreted in the urine.

Animals↗
PubMed1981

The role of peritoneoscopy in the diagnosis of acute abdominal conditions.

We have reported our experience with peritoneoscopy in patients with blunt abdominal trauma and in patients with suspected acute appendicitis. In our experience, the technique was associated with negligible morbidity and was effective in avoiding unnecessary laparotomy when properly applied. We believe that peritoneoscopy has not yet achieved its rightful place as a diagnostic procedure.

Abdomen, Acute↗
PubMedDate not supplied

Mercapturic acid conjugates as urinary end metabolites of the lipid peroxidation product 4-hydroxy-2-nonenal in the rat.

4-Hydroxy-2-nonenal (HNE), an aldehyde end product of lipid peroxidation in biological systems, is capable of producing a range of powerful biological effects. Despite its biological relevance, the metabolic fate of this aldehyde is unknown in vivo. This study examines the urinary excretion of HNE in the rat and the nature of metabolites formed. Following iv administration of [3H]HNE, the majority of the dose appeared in urine (67.1% after 48 h). The radio-HPLC metabolic profile showed that no unchanged parent compound was detected in urine whereas at least four metabolites were present, most of them corresponding to mercapturic acid conjugates. Two major pathways were involved in the biotransformation of HNE in vivo: (i) reduction/oxidation of the aldehyde group, and (ii) conjugation to endogenous glutathione leading to mercapturic acid conjugates in urine. These end products were isolated by HPLC and identified by mass spectrometry as HNE mercapturic acid, 1,4-dihydroxynonene mercapturic acid, 4-hydroxynonenoic mercapturic acid, and the corresponding lactone.

Acetylcysteine↗
PubMedDate not supplied

New aspects of metabolic conjugation of chloramphenicol.

New and major chloramphenicol (CP) metabolites have been isolated from the urine of goats administered [3H]CP. The CP-3-sulfoconjugate has been identified formally from its chromatographic behaviour and mass spectrometric analysis, as well as from incubations of CP with liver cytosol, using synthetic CP-conjugate as reference. Only a strong assumption is made of the identity of the CP-3-phosphoconjugate.

Animals↗