Prednisone treatment causes protein wasting and adds additional risks to a patient, whereas human growth hormone (hGH) treatment causes positive nitrogen balance. To determine whether concomitant administration of hGH prevents the protein catabolic effects of prednisone, four groups of eight healthy volunteers each were studied using isotope dilution and nitrogen balance techniques after 7 d of placebo, hGH alone (0.1 mg.kg-1.d-1), prednisone alone (0.8 mg.kg-1.d-1), or prednisone plus hGH (n = 8 in each group). Whether protein balance was calculated from the leucine kinetic data or nitrogen balance values, prednisone alone induced protein wasting (P less than 0.001), whereas hGH alone resulted in positive (P less than 0.001) protein balance, when compared to the placebo-treated subjects. When hGH was added to prednisone therapy, the glucocorticoid-induced protein catabolism was prevented. Using leucine kinetic data, negative protein balance during prednisone was due to increased (P less than 0.05) proteolysis, whereas hGH had no effect on proteolysis and increased (P less than 0.01) whole body protein synthesis. During combined treatment, estimates of proteolysis and protein synthesis were similar to those observed in the placebo treated control group. In conclusion, human growth hormone may have a distinct role in preventing the protein losses associated with the administration of pharmacologic doses of glucocorticosteroids in humans.

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Human growth hormone prevents the protein catabolic side effects of prednisone in humans.

Carbon isotopic compositions have been measured for individual hydrocarbons and monocarboxylic acids from the Murchison meteorite, a C2 carbonaceous chondrite which fell in Australia in 1969. With few exceptions, notably benzene, the volatile products are substantially isotopically heavier than their terrestrial counterparts, signifying their extraterrestrial origin. For both classes of compounds, the ratio of C-13 to C-12 decreases with increasing carbon number in a roughly parallel manner, and each carboxylic acid exhibits a higher isotopic ratio than the hydrocarbon containing the same number of carbon atoms. These trends are consistent with the kinetically controlled synthesis of higher homologues from lower ones. The results suggest the possibility that the production mechanisms for hydrocarbons and carboxylic acids may be similar, and impose constraints on the identity of the reactant species.

Carbon isotope composition of low molecular weight hydrocarbons and monocarboxylic acids from Murchison meteorite

The chemical mechanisms that lead to the formation and destruction of molecules in the interstellar gas are reviewed. Grain surface catalysis is discussed briefly. Detailed attention is given to gas-phase chemical processes and to the modifications they produce in the molecular compositions of interstellar clouds following the initial molecular formation. The effects of chemical fractionation processes on the abundances of molecules containing different isotopes are explored. The review was completed in March 1976.

http://iopscience.iop.org/article/10.1088/0034-4885/39/6/002/pdf

Molecule formation in the interstellar gas

C1 and C2 carbonaceous chondrites contain several percent of organic matter, mainly as a bridged aromatic polymer containing COOH, OH, and CO groups, as well as heterocyclic rings containing N, O, and S. The remaining 5–30% includes the following compound classes, either present initially or generated by solvolysis: alkanes (mainly normal), alkenes, arenes, alicyclics, alcohols, aliphatic carboxylic acids, purines, pyrimidines, and other basic N-compounds, amino acids, porphyrin-like pigments, carbynes, etc.

Organic compounds in meteorites and their origins

Organic compounds in meteorites seem to have formed by catalytic reactions of CO, H2, and NH3 in the solar nebula, at 360 degrees to 400 degrees K and (4 to 10) x 10-6 atm. The onset of these reactions was triggered by the formation of suitable catalysts (magnetite, hydrated silicates) at these temperatures. These reactions may be a source of prebiotic carbon compounds on the inner planets, and interstellar molecules.

https://science.sciencemag.org/content/sci/182/4114/781.full.pdf

Organic Compounds in Meteorites: They may have formed in the solar nebula, by catalytic reactions of carbon monoxide, hydrogen, and ammonia

Carbonaceous chondrite and Precambrian chert amino acids detection, using simultaneous optical configuration determination and gas chromatography

E. Gil-Av

Papers

Configuration of amino-acids in carbonaceous chondrites and a Pre-Cambrian chert.

Study of the racemization of some neutral α-amino acids in acid solution using gas chromatographic techniques

Retention der konfig. in der festphasensynth. von peptiden