Amino Acid Incorporation into Protein by Cell-Free Systems from Rat Skeletal Muscle. V. Effects of Pituitary Growth Hormone on Activity of Ribosomes and Ribonucleic Acid Polymerase in Hypophysectomized Rats*

Biochemistry ◽  
1966 ◽  
Vol 5 (6) ◽  
pp. 1870-1876 ◽  
Author(s):  
James R. Florini ◽  
Charles B. Breuer
1984 ◽  
Vol 247 (5) ◽  
pp. E639-E644
Author(s):  
C. M. Cameron ◽  
J. L. Kostyo ◽  
J. A. Rillema ◽  
S. E. Gennick

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.


1964 ◽  
Vol 239 (6) ◽  
pp. 1762-1768 ◽  
Author(s):  
Rusty J. Mans ◽  
Caridad Maria Purcell ◽  
G. David Novelli

1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday

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.


Sign in / Sign up

Export Citation Format

Share Document