scholarly journals Effect of premature weaning on amino acid uptake by the mammary gland of lactating rats

1981 ◽  
Vol 200 (3) ◽  
pp. 705-708 ◽  
Author(s):  
J R Viña ◽  
I R Puertes ◽  
J Viña
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Mammary Glands ◽  
Acid Uptake ◽  
Gamma Glutamyltransferase ◽  
Gamma Glutamyl ◽  
Lactating Mammary Gland

1. Arteriovenous differences of amino acids across the lactating mammary gland were measured in normal rats and weaned for 4, 5 and 24h. 2. Uptake of amino acids by mammary glands of rats weaned for 5h or more was significantly lower than that of controls. This was not reversed by injection of prolactin. 3. By using ‘unilaterally weaned’ rats we showed that milk accumulation plays an important role in amino acid uptake by mammary gland. 4. gamma-Glutamyltransferase activity was significantly lower in ‘weaned’ glands than in ‘normal’ glands. This provides further support for the hypothesis of the function of the gamma-glutamyl cycle in the mammary gland in vivo.

scholarly journals Involvement of γ-glutamyltransferase in amino-acid uptake by the lactating mammary gland of the rat

1981 ◽  
Vol 194 (1) ◽  
pp. 99-102 ◽  
Author(s):  
J Viña ◽  
I R Puertes ◽  
J M Estrela ◽  
J R Viña ◽  
J L Galbis
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Reduced Glutathione ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Gamma Glutamyltransferase ◽  
Lactating Mammary Gland ◽  
High Concentrations

1. Arteriovenous differences of amino acids across the lactating mammary gland have been measured in normal rats and in rats injected with serine–borate (an inhibitor of gamma-glutamyltransferase). 2. Comparison of the arteriovenous differences show that gamma-glutamyltransferase is involved in amino-acid uptake by the gland. 3. Reduced-glutathione content of isolated acini incubated with high concentrations of amino acids was lower than that of the controls. 4. High concentrations of amino acids had no effect on reduced-glutathione content of isolated acini when serine–borate was added to the incubation medium. 5. The findings provide evidence for the functioning of the gamma-glutamyl cycle in the lactating mammary gland in vivo.

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

Are the γ-glutamyl-amino acids signals for the amino acid uptake by lactating mammary gland?

1986 ◽  
Vol 14 (2) ◽  
pp. 311-312 ◽  
Author(s):  
JUAN R. VIÑA ◽  
INMACULADA R. PUERTES ◽  
JUAN B. MONTORO ◽  
ARGIMIRO RODRIGUEZ ◽  
JOSÉ VIÑA
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Lactating Mammary Gland

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

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

Effects of increased supply of essential amino acids on the metabolism of the isolated perfused guinea-pig mammary gland

1979 ◽  
Vol 46 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Andrew R. Peters ◽  
Stephen Alexandrov ◽  
T. Ben Mepham
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Mammary Gland ◽  
Amino Acid ◽  
Guinea Pig ◽  
Amino Acid Uptake ◽  
Essential Amino Acids ◽  
Acid Uptake ◽  
Isoleucine Leucine ◽  
Group 1

SUMMARYThe effects of high rates of infusion of essential amino acids on amino acid uptake by the isolated perfused guinea-pig mammary gland were studied. Infusion of methionine, tyrosine, phenylalanine, histidine and tryptophan (designated group 1) resulted in significant increases in the uptakes of tyrosine, phenylalanine and histidine. Methionine, tryptophan and other essential amino acids were not significantly affected. Infusion of threonine, valine, isoleucine, leucine, lysine and arginine (designated group 2) resulted in significant increases in uptake of all these amino acids. Group 1 amino acid uptake was not significantly affected. Infusion of all the essential amino acids (i.e. groups 1 and 2 together) resulted in significant increases in all their uptakes. Using as index ‘the predicted rate of protein synthesis’, infusion of group 1 and 2 together led to an apparent 27% increase in protein synthesis. The above results are discussed in relation to the control of milk protein synthesis by limiting essential amino acids.

scholarly journals Role of prolactin in amino acid uptake by the lactating mammary gland of the rat

FEBS Letters ◽  
1981 ◽  
Vol 126 (2) ◽  
pp. 250-252 ◽  
Author(s):  
José Viña ◽  
Inmaculada R. Puertes ◽  
Guillermo T. Saez ◽  
Juan R. Viña
Keyword(s):  
Mammary Gland ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Lactating Mammary Gland

scholarly journals Effect of starvation and refeeding on amino acid uptake by mammary gland of the lactating rat. Role of ketone bodies

1983 ◽  
Vol 216 (2) ◽  
pp. 343-347 ◽  
Author(s):  
J R Viña ◽  
I R Puertes ◽  
J B Montoro ◽  
J Viña
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Ketone Bodies ◽  
Total Concentration ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Arterial Concentration ◽  
Blood Ketone Bodies

Arteriovenous differences of amino acids across the mammary glands of lactating rats are diminished when the rats are starved for 24 h. When 24 h-starved rats were refed for 2 1/2 h, the arteriovenous differences of amino acids returned to values similar to those found in well-fed rats. In order to find a possible explanation for these rapid changes, we tested the effect of ketone bodies on amino acid uptake by the gland. At 5 min after injection of acetoacetate to fed rats, when the total concentration of ketone bodies in blood was similar to that found in starvation, the uptake of amino acids by the mammary gland was similar to that found after starvation, i.e. lower than in fed rats. However, 30 min after administration of acetoacetate, when the arterial concentration of ketone bodies had returned to values similar to those in fed rats, the arteriovenous differences of amino acids were similar to those found in fed rats. We conclude that the changes in blood ketone bodies may be responsible, at least in part, for the changes in amino acid uptake that occur in starvation and in the starvation—refeeding transition.

scholarly journals Amino Acid Sensing and Assimilation by the Fungal Pathogen Candida albicans in the Human Host

Pathogens ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 5
Author(s):  
Fitz Gerald S. Silao ◽  
Per O. Ljungdahl
Keyword(s):  
Amino Acids ◽  
Candida Albicans ◽  
Amino Acid ◽  
Fungal Pathogens ◽  
Close Association ◽  
Amino Acid Uptake ◽  
Nutrient Sensing ◽  
Acid Uptake ◽  
Uptake And Metabolism

Nutrient uptake is essential for cellular life and the capacity to perceive extracellular nutrients is critical for coordinating their uptake and metabolism. Commensal fungal pathogens, e.g., Candida albicans, have evolved in close association with human hosts and are well-adapted to using diverse nutrients found in discrete host niches. Human cells that cannot synthesize all amino acids require the uptake of the “essential amino acids” to remain viable. Consistently, high levels of amino acids circulate in the blood. Host proteins are rich sources of amino acids but their use depends on proteases to cleave them into smaller peptides and free amino acids. C. albicans responds to extracellular amino acids by pleiotropically enhancing their uptake and derive energy from their catabolism to power opportunistic virulent growth. Studies using Saccharomyces cerevisiae have established paradigms to understand metabolic processes in C. albicans; however, fundamental differences exist. The advent of CRISPR/Cas9-based methods facilitate genetic analysis in C. albicans, and state-of-the-art molecular biological techniques are being applied to directly examine growth requirements in vivo and in situ in infected hosts. The combination of divergent approaches can illuminate the biological roles of individual cellular components. Here we discuss recent findings regarding nutrient sensing with a focus on amino acid uptake and metabolism, processes that underlie the virulence of C. albicans.

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