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R Erikson

Publications and source records attributed to R Erikson.

5 recordsLinked to original sources
PubMed1996

New aspects of lactate metabolism: IGF-I and insulin regulate mitochondrial function in cultured brain cells during normoxia and hypoxia.

Using 13C nuclear magnetic resonance spectroscopy in combination with conventional biochemical techniques, effects of insulin and IGF-I on energy metabolism and cell viability were studied in cerebral cortical neurons, astrocytes and cocultures thereof during normoxia and hypoxia. Lactate dehydrogenase leakage was used to monitor the cytoprotective effects of IGF-I and insulin. Thus, during normoxia both peptides decreased LDH leakage from neurons. During hypoxia, however, this protection was only observed when insulin was present. Interestingly, neurons showed much less LDH leakage during hypoxia than astrocytes or cocultures. A possible explanation could be an increased glycolysis in neurons. Thus, lactate production and glucose consumption were increased severalfold in neurons during hypoxia whereas astrocytes and cocultures only showed a slight increase. Both insulin and IGF-I increased glucose metabolism during normoxia in astrocytes but not in neurons, whereas during hypoxia this increase was less pronounced. Using [1-13C]glucose it could be demonstrated that production of lactate from mitochondrial precursors was, in the presence of insulin or IGF-I, down regulated in astrocytes but increased in neurons during normoxia. This route for lactate production was not used during hypoxia and incorporation into the C-3 position of lactate approached the theoretical maximum of 50%.

Animals↗
PubMed1995

13C NMR study of IGF-I- and insulin-effects on mitochondrial function in cultured brain cells.

Development of differential cell culture systems has facilitated the study of cellular and physiological actions of growth factors. Here we report the novel effects of insulin and insulin-like growth factor (IGF)-I on energy metabolism in cerebral cortical neurones, astrocytes and co-cultures thereof. Incorporation of label from [1-13C]glucose into lactate has been shown to involve both glycolysis and the tricarboxylic acid cycle in astrocytes. Thus 13C nuclear magnetic resonance spectroscopy was used to monitor mitochondrial function by measuring 13C labelling of the C-2 position of lactate. It could be demonstrated that insulin and IGF-I have similar effects on mitochondria but individual effects on cytosolic glucose metabolism. Evidence is presented that IGF-I and insulin stimulate neurones to release factors affecting astrocytic lactate production. Furthermore, lactate released from neuronal-astrocytic co-cultures was mostly of astrocytic origin, implicating the importance of lactate for neuronal metabolism.

Animals↗
PubMed1976

Depression and daily temperature. A long-term study.

In a long-term observation of a manic-depressive female patient, three depressive episodes and two intervals without complaints were studied. During this period, the oral temperature was measured every 3 h. The temperature values were compared with a self-rating scale of the patient. The oral temperature showed a different pattern on the depressive days as compared with the interval days. The average temperature values were higher on depressive days. During the depression, changes were found in the daily temperature rhythm which resulted in a temperature maximum earlier in the day. The changes can be explained as indicating a desynchronization phenomenon of the circadian rhythms.

Adult↗