The effects of mammalian prolactin and growth hormone on goldfish (Carassius auratus) growth, plasma amino acid levels and liver amino acid uptake

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.

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Action of insulin and growth hormone on protein synthesis in muscle from non-hypophysectomized rabbits

Biochemical Journal ◽

10.1042/bj1250515 ◽

1971 ◽

Vol 125 (2) ◽

pp. 515-520 ◽

Cited By ~ 13

Author(s):

P. J. Reeds ◽

K. A. Munday ◽

M. R. Turner

Keyword(s):

Amino Acids ◽

Growth Hormone ◽

Protein Synthesis ◽

Amino Acid ◽

Incubation Medium ◽

Amino Acid Uptake ◽

Diaphragm Muscle ◽

Acid Uptake

The separate effects of insulin and growth hormone on the uptake and incorporation of five amino acids into diaphragm muscle from non-hypophysectomized rabbits has been examined. Both growth hormone and insulin, when present in the medium separately, stimulated the incorporation into protein of the amino acids, leucine, arginine, valine, lysine and histidine. Insulin also stimulated amino acid uptake, but growth hormone did not. When insulin and growth hormone were present in the incubation medium together, the uptake and incorporation of valine, the only amino acid studied under these conditions, tended to be greater than the sum of the separate effects of the two hormones.

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Daily rhythms of amino acid levels in the plasma of goldfish (Carassius auratus)

Comparative Biochemistry and Physiology Part A Physiology ◽

10.1016/0300-9629(80)90244-3 ◽

1980 ◽

Vol 67 (4) ◽

pp. 581-586 ◽

Cited By ~ 9

Author(s):

M Carrillo ◽

S Zanuy ◽

E Herrera

Keyword(s):

Amino Acid ◽

Carassius Auratus ◽

Daily Rhythms ◽

Goldfish Carassius Auratus ◽

Amino Acid Levels

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Plasma amino acid uptake by the mammary gland of the lactating sow.

Journal of Animal Science ◽

10.2527/1997.7551266x ◽

1997 ◽

Vol 75 (5) ◽

pp. 1266 ◽

Cited By ~ 61

Author(s):

N L Trottier ◽

C F Shipley ◽

R A Easter

Keyword(s):

Mammary Gland ◽

Amino Acid ◽

Amino Acid Uptake ◽

Plasma Amino Acid ◽

Acid Uptake ◽

Lactating Sow

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Insulin resistance and regulation of serum amino acid levels in myotonic dystrophy

Clinical Science ◽

10.1042/cs0710429 ◽

1986 ◽

Vol 71 (4) ◽

pp. 429-436 ◽

Cited By ~ 8

Author(s):

Richard T. Moxley ◽

William J. Kingston ◽

Kenneth L. Minaker ◽

Alastair J. Corbett ◽

John W. Rowe

Keyword(s):

Insulin Resistance ◽

Amino Acid ◽

Myotonic Dystrophy ◽

Insulin Infusion ◽

Normal Subjects ◽

Amino Acid Uptake ◽

Whole Body ◽

Glucose Disposal ◽

Acid Uptake ◽

Amino Acid Levels

1. To quantify the degree of whole body insulin resistance in patients with myotonic dystrophy and to determine if these same patients display signs of a whole body decrease in the action of insulin on amino acid uptake and glucose disposal, three separate 120 min studies employing the euglycaemic insulin clamp technique (20, 80 and 200 m-units min−1 m−2) were performed on five ambulatory patients with myotonic dystrophy. The results were compared with findings obtained in identical studies in 21 normal volunteers. 2. Myotonic dystrophy patients showed a slower, less marked decline in the serum concentration of insulin sensitive amino acids (threonine, valine, leucine, isoleucine, tyrosine, phenylalanine) during all three insulin infusions compared with normals. The greatest difference occurred at the low physiological elevations of insulin produced by the 20 m-units min−1 m−2 infusion. 3. Alanine levels fell significantly below baseline in patients with myotonic dystrophy after 60 and 120 min of insulin infusion with all three rates of insulin infusion. Normal subjects had only a minimal, insignificant decline in arterialized alanine concentrations during the three different insulin infusions. 4. Creatinine adjusted rates of whole body glucose disposal were 30–40% lower in the myotonic dystrophy group at all three doses of insulin compared with the normals. This demonstrates that their insulin resistance was not due simply to a reduction in muscle mass. 5. The overall pattern of findings in these studies of patients with myotonic dystrophy indicates that there is a whole body derangement in the regulation of circulating amino acid levels by insulin as well as a marked decrease in the action of this hormone in stimulating glucose uptake by target tissues.

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Influence of plasma amino acid level on urine volume in the alligator

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1962.202.1.83 ◽

1962 ◽

Vol 202 (1) ◽

pp. 83-87 ◽

Cited By ~ 9

Author(s):

Roland A. Coulson ◽

Thomas Hernandez

Keyword(s):

Amino Acids ◽

Growth Hormone ◽

Amino Acid ◽

Ammonia Synthesis ◽

Amino Acid Level ◽

Urine Volume ◽

Plasma Amino Acid ◽

Protein Catabolism ◽

Degree Of Hydration ◽

Amino Acid Levels

Growth hormone, hydrocortisone, and a mixture of the two were injected daily into small alligators for periods up to 2 weeks. Although plasma amino acid levels increased only slightly after either growth hormone or hydrocortisone, injection of the combined hormones doubled the concentrations. In all cases increases in plasma amino acids were associated with an augmented renal ammonia synthesis and an increased urine volume. When the degree of hydration was maintained at a nearly constant level, the urine volume was directly related to the quantity of amino acids available for renal deamination. Insulin, a hormone which lowers the concentration of extracellular amino acids, decreased the rate of renal ammonia synthesis and therefore the rate of urine flow. The oliguria produced by insulin could be counteracted by the injection of glycine, a known precursor of urinary ammonia. Evidence is presented which suggests that in the "diabetes" caused by a combined injection of growth hormone and hydrocortisone, protein catabolism is enhanced and fat catabolism is inhibited. A negative nitrogen balance occurred as a result of the delivery of more amino acids for renal deamination.

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Valine entry into rat brain after diet-induced changes in plasma amino acids

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.252.1.r78 ◽

1987 ◽

Vol 252 (1) ◽

pp. R78-R84

Author(s):

J. K. Tews ◽

J. Greenwood ◽

O. E. Pratt ◽

A. E. Harper

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Protein Content ◽

Protein Intake ◽

Amino Acid Uptake ◽

Plasma Amino Acid ◽

Acid Uptake ◽

Induced Changes ◽

The Brain

Passage of amino acids across the blood-brain barrier is assumed to be modified by amino acid composition of the blood. To gain a better understanding of the effects of protein intake on brain amino acid uptake, we examined associations among diet, plasma amino acid patterns, and the rate of entry of valine into the brain. Rats were fed (8 h/day for 7–10 days) diets containing 6, 18, or 50% casein before receiving one meal of a diet containing 0, 6, 18, or 50% casein. After 4–7 h, they were anesthetized and infused intravenously with [14C]valine for 5 min before plasma and brain samples were taken for determination of radioactivity and content of individual amino acids. As protein content of the meal was increased from 0 to 50% casein, plasma and brain concentrations of valine and most other large neutral amino acids (LNAA) increased severalfold; also the ratio of [14C]valine in brain to that in plasma decreased by greater than 50%, and the rate of valine entry into the brain increased 3.5-fold. The increase in valine flux slowed as plasma levels of LNAA, competitors for valine transport, increased. The results were far more dependent on protein content of the final meal than on that of the adaptation diet; thus changes in protein intake, as reflected in altered plasma amino acid patterns, markedly altered valine entry into the brain.

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