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Biomedical subjects

R Goberna

Publications and source records attributed to R Goberna.

At least 91 records · Page 5Linked to original sources
PubMed1980

Effect of phosphoenolpyruvate on liver mitochondrial calcium retention from fed and fasted rats.

Rat liver mitochondria from fed and 4-day-fasted rats are able to accumulate calcium supported by ATP (energy-driven calcium uptake) or by succinate (respiration-driven calcium uptake). Phosphoenolpyruvate decreases the amount of calcium accumulated in both ways, whether the rats were fasted or fed ad libitum. Phosphoenolpyruvate induces a net calcium efflux from mitochondria. The effect of phosphoenolpyruvate is partially reversed by ADP. Phosphoenolpyruvate is also able to inhibit the ATP-driven calcium accumulation in the absence of exogenously added respiratory substrates.

Adenosine Diphosphate↗
PubMed1978

Effect of prolonged fasting upon insulin and glucagon secretion from isolated rat pancreatic islets.

To study insulin-glucagon interrelationships in the regulation of pancreatic islet functions, glucose-mediated insulin and glucagon secretion have been studied in isolated pancreatic islets from fed and from 4 and 8-day fasted rats. At low glucose levels (50 mg %) a continuous decrease of insulin and increase of glucagon secretion were observed during prolonged fasting. High glucose concentrations 300 mg %) stimulated insulin and inhibited glucagon secretion until 4 days, but did not cause any effect after 8 days fasting. These results suggest that the secretory mechanisms of the two hormones may have a common basis.

Animals↗
PubMed1978

Binding activity regulation of rabbit skeletal muscle adenosine 3'-5'-monophosphate-dependent protein kinases.

A cAMP-dependent protein kinase has been isolated from rabbit muscle and purified. The affinity constant of the enzyme for the nucleotide is Ka = 9.3 X 10(-9) M, with a Vmax = 0.013 X 10(12) moles bound cAMP/1 microgram protein. The influence exerted by different factors is studied: a) Inhibitor (I) of kinase activity: increases the binding capacity for cAMP, by percentages which depend on the amount of I. In the presence of inhibitor (120 microgram/100 microliter) the affinity constant is Ka = 4.1 X 10(-9) M, without change in Vmax. b) Effect of pH: it has a complex influence over binding, being also regulated by cAMP concentration. The positive effect on binding of ionic and bovine serum albumin concentrations, and the negative effect of enzyme preincubation before additions of (H3) cAMP, have also been studied. The importance of these effectors to obtain a high degree of sensitivity in the binding protein method has been assertained.

Animals↗