Protein Synthesis in the Rat Anterior Pituitary. I. Interrelationship of Amino Acid Uptake to Protein Synthesis

Samli, Marcqueta H.; Lai, Minchao; Barnett, Charlotte A.

doi:10.1210/endo-88-3-540

Cited by 19 publications

(2 citation statements)

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“…Each experimental point is the mean of three separate determinations. tissue concentration of [3H]leucine reaches a plateau value before the 2h time-point and remains at that value for at least another 3 h. This is in agreement with the results of Samli et al (1971). We also confirmed that total protein synthesis is approximately linear with time over the period studied.…”

Section: Effect Ofinsulin On the Incorporation Into Totalproteinsupporting

confidence: 91%

Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

Betteridge

Wallis

1973

Biochemical Journal

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The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2mum (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1-5mum-insulin (140-700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10mum (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

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Section: Effect Ofinsulin On the Incorporation Into Totalproteinsupporting

confidence: 91%

Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

Betteridge

Wallis

1973

Biochemical Journal

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“…Several authors have proposed that amino acids utilized for protein synthesis in mammalian tissues do not pass through the general amino acid pool of the cell (Hider et al, 1969;Samli et al, 1971). However, it is clear that in the present study the relative specific radioactivities of the amino acids in labelled somatotropin are not correlated with the specific radioactivities or the total quantities oflabelled amino acids in the incubation mixture.…”

Section: Discussionmentioning

confidence: 99%

Preparation of internally labelled rat pituitary somatotropin (growth hormone)

Wallis¹,

Davies²,

Daniels³

1978

Biochemical Journal

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Rat somatotropin (growth hormone) was labelled biosynthetically by incubating anterior pituitary lobes with radioactive amino acids for 24 h in a simple buffered salts medium containing glucose. The labelled hormone was isolated by preparative polyacrylamide-gel electrophoresis or by chromatography on Sephadex G-100 and then DEAE-cellulose. The labelled material was pure by several criteria and cross-reacted immunologically with unlabelled rat somatotropin. When a mixture of 14C-labelled amino acids was used for labelling the protein, label could be introduced into these same amino acids of somatotropin, though relative specific radioactivities varied considerably. Somatotropin labelled by the procedures described in the present paper was suitable for structural studies and could be used for a variety of other biochemical experiments.

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Amino acid transport in the rat exocrine pancreas

1977

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The transport and utilization of three neutral amino acids in protein synthesis was studied using isolated pancreatic lobules in vitro. The significance of the extracellular and intracellular amino acid pool in this process was analyzed removing the extracellular pool (labeled by inulin) by a cold-wash procedure. This was especially useful in short-term experiments. Double-labeling experiments indicated a predominant utilization of the intracellular amino acid pool during protein synthesis. The advantage of isolated pancreatic lobule preparations compared to tissue fragments or slices was emphasized by fine structural studies. Using freeze-etching techniques on the same preparations, differences in the distribution of membrane particles between luminal and lateral plasma membranes described earlier were confirmed, as well as the abundant occurrence of gap junctions on both membrane faces.

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Protein Synthesis in the Rat Anterior Pituitary. I. Interrelationship of Amino Acid Uptake to Protein Synthesis

Cited by 19 publications

References 0 publications

Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

Preparation of internally labelled rat pituitary somatotropin (growth hormone)

Amino acid transport in the rat exocrine pancreas

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