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AMP-activated protein kinase controls metabolism and heat production during embryonic development in birds

Abstract

During embryonic and early juvenile development, endotherms must balance energy allocation between growth and heat production. Failure to either match the ATP demand of growing tissue or produce heat at the correct developmental stage will lead to damage of the organism. We tested the hypothesis that AMP-activated protein kinase (AMPK) is involved in the regulation of energy metabolism and heat production during development in the chicken (Gallus gallus). We show that mRNA concentrations of regulatory and catalytic AMPK subunits, AMPK total protein, and AMPK phosphorylation increase during development [3 days (-3 days) and one day (-1 day) before hatching, and +1 day and +8 days after hatching] in liver, and to a lesser extent in skeletal muscle. Chronic stimulation with 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) significantly increases AMPK phosphorylation in skeletal muscle and in liver. This increase was paralleled by significant increases in heat production, glucose utilization, and liver and skeletal muscle mitochondrial capacity (citrate synthase activity). The effects of AMPK are likely to be mediated by inhibition of acetyl CoA carboxylase (ACC) after hatching, when ACC protein concentration increases significantly, and by a significant AMPK-induced increase in PGC-1 alpha mRNA concentration (at +1 day), but not in NRF-1 mRNA concentration. AMPK phosphorylation is under the control of thyroid hormone, and AMPK phosphorylation decreases significantly following the induction of hypothyroidism. We propose AMPK as a principal regulatory mechanism during the transition from ectothermy to endothermy in birds, and show that AMPK function in birds is similar to that observed in mammals.

Type Journal
ISBN 0022-0949
Authors Walter, I.; Hegarty, B.; Seebacher, F.;
Publisher Name JOURNAL OF EXPERIMENTAL BIOLOGY
Published Date 2010-01-01
Published Volume 213
Published Issue 18
Published Pages 3167-3176 181
Status Published in-print
URL link to publisher's version <Go to ISI>://CCC:000281385800016
OpenAccess link to author's accepted manuscript version https://publications.gimr.garvan.org.au/open-access/10835