scholarly journals Effects of hormones on protein and amino acid metabolism in mammary-gland explants of mice

1976 ◽  
Vol 158 (2) ◽  
pp. 355-359 ◽  
Author(s):  
L D Anderson ◽  
J A Rillema
Keyword(s):  
Mammary Gland ◽  
Amino Acid ◽  
Protein Biosynthesis ◽  
Insulin Response ◽  
Exposure Period ◽  
Amino Acid Uptake ◽  
Isobutyric Acid ◽  
Leucine Incorporation ◽  
Acid Uptake ◽  
Pregnant Mice

The effects of insulin, cortisol and prolactin on amino acid uptake and protein biosynthesis were determined in mammary-gland explants from mid-pregnant mice. Insulin stimulated [3H]leucine incorporation into protein within 15 min of adding insulin to the incubation medium. Insulin also had a rapid stimulatory effect on the rate of aminoiso[14C]butyric acid uptake, but it had no effect on the intracellular accumulation of [3H]leucine. Cortisol inhibited the rate of [3H]leucine incorporation into protein during the initial 4h of incubation, but it had no effect at subsequent times. [3H]Leucine uptake was unaffected by cortisol, but amino[14C]isobutyric acid uptake was inhibited after a 4h exposure period to this hormone. Prolactin stimulated the rate of [3H]leucine incorporation into protein when tissues were exposed to this hormone for 4h or more; up to 4h, however, no effect of prolactin was detected. At all times tested, prolactin had no effect on the uptake of either amino[14C]isobutyric acid or [3H]leucine. Incubation with actinomycin D abolished the prolactin stimulation of protein biosynthesis, but this antibiotic did not affect the insulin response. A distinct difference in the mechanism of action of these hormones on protein biosynthesis in the mammary gland is thus apparent.

Gamma-Glutamyl-Amino Acids as Signals for the Hormonal Regulation of Amino Acid Uptake by the Mammary Gland of the Lactating Rat

Neonatology ◽  
1985 ◽  
Vol 48 (4) ◽  
pp. 250-256 ◽  
Author(s):  
Juan R. Viña ◽  
Inmaculada R. Puertes ◽  
Juan B. Montoro ◽  
Guillermo T. Saez ◽  
José Viña
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Hormonal Regulation ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Gamma Glutamyl

Somatostatin inhibits insulin-stimulated amino acid uptake into cultured rat myoblasts

1987 ◽  
Vol 114 (4) ◽  
pp. 470-474 ◽  
Author(s):  
G. S. G. Spencer ◽  
D. J. Hill ◽  
G. J. Garssen ◽  
J. P. G. Williams
Keyword(s):  
Amino Acid ◽  
Nutrient Uptake ◽  
Monolayer Culture ◽  
Amino Acid Uptake ◽  
Inhibitory Effect ◽  
Isobutyric Acid ◽  
Acid Uptake ◽  
Newborn Rat ◽  
Amino Isobutyric Acid

Abstract. The effects of somatostatin on the acute metabolic actions of insulin on newborn rat myoblasts in culture has been examined during monolayer culture. Somatostatin significantly inhibited the insulin-stimulated uptake of [3H]leucine and [3H]amino-isobutyric acid into myoblasts but had no effect on basal (unstimulated) uptake of these two substances. The lowest concentration of somatostatin to have a significant effect was 10 μg/l, and this was apparent in all the experiments undertaken. The inhibitory effect of somatostatin was seen at all effective concentrations of insulin used (0.3–1 U/l). These findings lend support to the concept of an endocrine role for somatostatin in vivo and suggest that a peripheral antagonism may exist between circulating insulin and somatostatin on anabolic processes such as nutrient uptake into cells.

Blood flow and net amino acid uptake by the lactating mammary gland: effect of starvation

1985 ◽  
Vol 13 (5) ◽  
pp. 876-877 ◽  
Author(s):  
JUAN R. VIÑA ◽  
ARGIMIRO RODRIGUEZ ◽  
JUAN B. MONTORO ◽  
ANTONIO IRADI ◽  
INMACULADA R. PUERTES ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mammary Gland ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Lactating Mammary Gland

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

1997 ◽  
Vol 75 (5) ◽  
pp. 1266 ◽  
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

Effects of phenylarsine oxide on insulin-stimulated system A amino acid uptake in skeletal muscle

1991 ◽  
Vol 261 (4) ◽  
pp. C608-C613 ◽  
Author(s):  
E. J. Henriksen
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Isobutyric Acid ◽  
Acid Uptake ◽  
Mammalian Skeletal Muscle ◽  
Phenylarsine Oxide ◽  
System A ◽  
Carrier Molecule ◽  
20 Nm

The role of vicinal sulfhydryls in the stimulation by insulin of system A amino acid uptake in mammalian skeletal muscle was investigated. Neutral amino acid uptake via system A carriers was assessed using the nonmetabolizable analogue alpha-(methylamino)isobutyric acid (MeAIB). Phenylarsine oxide (PAO), a trivalent arsenical that interacts with vicinal sulfhydryls, at 40 microM inhibited basal and insulin-stimulated (2 mU/ml) MeAIB uptake in rat epitrochlearis muscles by approximately 50% and approximately 80%, respectively. No significant changes in the ATP level or in the lactate-to-pyruvate ratio were observed. Both inhibitory effects were completely preventable by coincubation with dimercaptopropanol, a vicinal dithiol, indicating the effects were mediated specifically by interactions with vicinal sulfhydryls. Stimulation of MeAIB uptake by the insulin-mimicker vanadate (10 mM) or by insulin-like growth factor I (IGF-I, 20 nM) was also inhibited by 80-90% by PAO. Kinetic analysis showed that PAO decreased the apparent Vmax for basal and insulin-stimulated MeAIB uptake without altering the apparent Km. MeAIB uptake already maximally stimulated by insulin was rapidly (half-time = approximately 10 min) reversed by the addition of PAO so that the rate of MeAIB uptake was the same as in muscles incubated throughout with insulin and PAO. These results implicate a major role for vicinal sulfhydryls in the stimulation by insulin of amino acid uptake via system A carriers in skeletal muscle and suggest that the site of action of PAO on this system is distal to the insulin receptor, possibly at the carrier molecule itself.

Control of amino acid uptake by the lactating mammary gland of the rat

1981 ◽  
Vol 9 (5) ◽  
pp. 392-392 ◽  
Author(s):  
JUAN R. VIÑA ◽  
JUAN B. MONTORO ◽  
INMACULADA R. PUERTES ◽  
JOSE VIÑA
Keyword(s):  
Mammary Gland ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Lactating Mammary Gland

ASC system activity is altered by development of cell polarity in trophoblast from human placenta

1993 ◽  
Vol 265 (1) ◽  
pp. C212-C217 ◽  
Author(s):  
T. C. Furesz ◽  
C. H. Smith ◽  
A. J. Moe
Keyword(s):  
Amino Acid ◽  
Primary Cultures ◽  
Amino Acid Uptake ◽  
Selective Inhibition ◽  
Isobutyric Acid ◽  
Neutral Amino Acid ◽  
Transport Systems ◽  
Bewo Cell ◽  
Acid Uptake

Pathways of neutral amino acid uptake were investigated in vitro during differentiation of primary cultures of trophoblast isolated from full-term human placentas and a clone (b30) of the BeWo cell line. Inhibition of initial alanine (0.1 microM) uptake by 2-(methylamino)isobutyric acid and unlabeled alanine revealed two Na(+)-dependent systems and one Na(+)-independent transporter. Characterization of these transporters, by selective inhibition, suggested system A, ASC, and L-like transporters. Concomitant with formation of microvillous membrane and syncytium, system ASC activity decreased from 16.1 +/- 2.8 pmol.mg DNA-1.min-1 at 24 h to 2.4 +/- 1.1 pmol.mg DNA-1.min-1 at 72 h. Na(+)-independent alanine uptake increased from 6.0 +/- 2.0 to 12.9 +/- 0.9 pmol.mg DNA-1.min-1 at 24 and 72 h, respectively. Similarly, alpha-(methylamino)isobutyric acid-insensitive, Na(+)-dependent activity in b30 cells (100 microM alanine) decreased from 6.5 +/- 1.6 to 1.2 +/- 1.2 nmol.mg DNA-1.min-1 for control and forskolin-treated cells, respectively. We conclude that membrane specialization accompanying fusion and differentiation of the cytotrophoblast to form syncytiotrophoblast results in a polarization of neutral amino acid transport systems.

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