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E M Baker

Publications and source records attributed to E M Baker.

17 recordsLinked to original sources
PubMed1985

Cyclic AMP inhibits secretion from bovine adrenal chromaffin cells evoked by carbamylcholine but not by high K+.

The role of cAMP in the control of secretion from bovine adrenal chromaffin cells was examined using the adenylate cyclase activator, forskolin. Treatment of chromaffin cells with forskolin resulted in a rise in cAMP levels. Forskolin inhibited catecholamine release elicited by carbamylcholine or nicotine but had no effect on secretion evoked by 55 mM K+. Inhibition of carbamylcholine-stimulated release by forskolin was half-maximal at 10 microM forskolin. The inhibition by forskolin of secretion evoked by carbamylcholine was at a step distal to the rise in intracellular free calcium concentration ([Ca2+]i), since this rise was not inhibited by forskolin, which itself produced a small rise in [Ca2+]i. The results suggest that secretion evoked by carbamylcholine is due to the activation of an additional second messenger pathway acting with the rise in [Ca2+]i. This additional pathway may be the target for cAMP action.

Adrenal Medulla↗
PubMed1975

Metabolism of ascorbic acid and ascorbic-2-sulfate in man and the subhuman primate.

Man does not catabolize ascorbate to CO2, whereas the monkey does catabolize ascorbate and ascorbate sulfate to CO2 when these compounds are given orally. However, it takes the same length of time to produce frank scurvy in both man and the monkey, thus indicating that the comparative storage, rate of use, and mode of metabolism of ascorbate is similar in both species. Preliminary feeding and isotope studies conducted on monkeys are in agreement with the fact that only a small amount of labeled ascorbate or ascorbate sulfate equilibrated with body stores. These results are in agreement with published ascorbic acid requirements of 10 mg/kg body weight. In our experiments, 250 mg/day had to be fed to a 10-kg monkey to completely clear all signs of scurvy and return blood ascorbate levels to normal. Ascorbic acid administered intravenously to monkeys appears to equilibrate completely with the ascorbate pool(s). Ascorbate sulfate was found to be a urinary metabolite of both ascorbic-1-14C acid and ascorbic-6-14C acid fed orally to monkeys.

Animals↗