POMC and pyruvate dehydrogenase deficiency: Based on the observed variation and effect size, an alpha of .05 and 80% power, a sample size of 16 animals per group would be needed to detect a significant difference in serum serotonin, indicating that the serotonin assay was underpowered to detect a significant difference, Serum serotonin values did not correlate significantly with post‐ACTH cortisol in either dogs with SARDS or dogs with PDH (data not shown).