Computer analysis of amino acid chromatograms

Exss, R; Hill, Helene Z.; Summer, George K.

doi:10.1016/s0021-9673(01)80652-x

Cited by 15 publications

(2 citation statements)

References 7 publications

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“…using a 140 X 0.9 cm (ID) column packed with chromabeads resin, type A. The ornithine peak was readily separable from that of other amino acids during a 23 h run and was quantitated from the area under the peak as previously described (13).…”

Section: Methodsmentioning

confidence: 99%

Regulation of Adrenal Ornithine Decarboxylase by Adrenocorticotropic Hormone and Cyclic AMP

Richman¹,

Dobbins²,

Voina³

et al. 1973

J. Clin. Invest.

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A B S T R A C T Adrenal ornithiine decarboxylase activity was stimulated in a dose-related manner after administration of ACTH or dibutyryl (6N-2'-O-dibutyryl) cyclic AMP to hypophysectomized rats. Little effect was observed for 2 h, but striking increases in enzyme activity were observed 4 h after administration of these substances. Effects of ACTH and dibutyryl cyclic AMP were not secondary to stimulation of steroidogenesis, since hydrocortisone had no effect on adrenal ornithine decarboxylase although it did stimulate activity of the enzyme in the liver and kidney.ACTH, given subcutaneously to hypophysectomized rats, induced striking increases in adrenal cyclic AMP levels within 15-30 min with a fall towards the base line in 1 h. Increases in ornithine decarboxylase activity lag several hours after this endogenous cyclic AMP peak, in contrast to the stimulation of steroidogenesis by the nucleotide that requires only 2-3 min. After graded doses of ACTH, increases in adrenal cyclic AMP levels at 30 min were paralleled by proportional increases in adrenal ornithine decarboxylase activity 4 h after hormone treatment. Whereas maximal levels of adrenal steroidogenesis have been observed at tissue cyclic AMP levels of 6 nmol/g, ACTH is capable of inducing increases in nucleotide levels up to 200 nmol/g or more. These high tissue levels of cyclic AMP, although unnecessary for maximal steroidogenesis, appear to stimulate adrenal ornithine decarboxylase activity.Several results in addition to the time lag in the stimulation of ornithine decarboxylase activity suggest a mechanism involving accumulation of the enzyme or some factor needed for its activity rather than direct activation of the enzyme by cyclic AMP. Thus, the addition of cyclic AMP directly to the ornithine decarboxylase assay mixture in vitro was without stimulatory Receiz'ed for publication 5 May 1972 and in revised form 27 March 1973. effect. In addition, actinomycin D or cycloheximide in doses sufficient to block adrenal RNA and protein synthesis, respectively inhibited the stimulation of ornithine decarboxylase activity by ACTH in vivo. An adrenocortical cancer was found to maintain ornithine decarboxylase activity at very high levels, but did so at much lower cyclic AMP levels than those of ACTH-stimulated adrenals.It is concluded that ACTH stimulates adrenal ornithine decarboxylase activity and that this effect may be mediated by cyclic AMP. However, cyclic AMP does not appear to be a determinant of the high level of enzyme activity found in adrenocortical cancer.

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Section: Methodsmentioning

confidence: 99%

Regulation of Adrenal Ornithine Decarboxylase by Adrenocorticotropic Hormone and Cyclic AMP

Richman¹,

Dobbins²,

Voina³

et al. 1973

J. Clin. Invest.

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“…Complex mixtures separated by drycolumn chromatography are analyzed by breaking the column into segments which are inserted directly into a mass spectrometer (25). A computer program is described (109) for the identification and quantitative analysis of protein amino acids from the output of the integrator attached to an automatic amino acid analyzer. Use of peak heights for the quantitation of amino acids is also accurate and reliable (308).…”

Section: Nucleic Acids Have Been Fractionatedmentioning

confidence: 99%