The effect of malathion on amino acid incorporation into plasma membrane proteins of Vigna sinensis (L): Effect of plant growth hormone supplementation.

The biological activity profile of reduced and S-carboxymethylated human growth hormone (RCM-hGH) was determined to establish its suitability for study of the diabetogenic property of hGH. RCM-hGH was found to have greatly attenuated in vivo growth-promoting activity in the 9-day weight-gain test in hypophysectomized rats (approximately 1%) and to have a similar low order of in vitro activity in stimulating amino acid incorporation into the protein of the isolated rat diaphragm. RCM-hGH also only had approximately 1% of the in vitro insulin-like activity of the native hormone on isolated adipose tissue from hypophysectomized rats. In contrast, RCM-hGH retained substantial in vivo diabetogenic activity in the ob/ob mouse, appearing to have approximately 50% of the activity of the native hormone. RCM-hGH was also found to retain significant, although attenuated (25%), in vitro lactogenic activity when tested for the ability to stimulate amino acid incorporation into a casein-rich protein fraction in mouse mammary gland explants. Because RCM-hGH exhibits a high degree of diabetogenic activity, although lacking significant anabolic or insulin-like activities, it will be useful as a "monovalent" probe for the study of the molecular mechanism of the diabetogenic action of GH.

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Action of growth hormone in vitro on the net uptake and incorporation into protein of amino acids in muscle from intact rabbits given protein-deficient diets

British Journal Of Nutrition ◽

10.1079/bjn19760003 ◽

1976 ◽

Vol 35 (1) ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

M. R. Turner ◽

P. J. Reeds ◽

K. A. Munday

Keyword(s):

Amino Acids ◽

Growth Hormone ◽

Protein Synthesis ◽

Amino Acid ◽

De Novo ◽

Amino Acid Uptake ◽

Acid Uptake ◽

Amino Acid Incorporation ◽

Acid Incorporation

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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Effect of Curvularia lunata phytotoxin on membrane permeability of corn roots

Canadian Journal of Botany ◽

10.1139/b76-314 ◽

1976 ◽

Vol 54 (24) ◽

pp. 2918-2923 ◽

Cited By ~ 5

Author(s):

A. Vianello ◽

F. Macrì ◽

C. Passera

Keyword(s):

Protein Synthesis ◽

Plasma Membrane ◽

Amino Acid ◽

Active Transport ◽

Curvularia Lunata ◽

Amino Acid Incorporation ◽

Corn Roots ◽

Acid Incorporation ◽

Specific Membrane ◽

General Plasma

Corn roots exposed to the Curvularia lunata phytotoxin show a decreased ability to absorb and to retain rubidium, sulphate, and leucine compared with control roots. The phytotoxin also decreased the amount of the amino acid incorporation into protein, whereas respiration was only slightly affected. The effect on active transport was more pronounced and rapid than loss of ions and inhibition of protein synthesis. The data suggest that the phytotoxin causes a general plasma membrane derangement similar to that caused by other phytotoxins, which results in a depression of the active transport, reflected in an inhibition of precursors of proteins and in a loss of ions. The toxin is to be regarded as a specific membrane poison.

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