ACOX3 and hypothyroidism: A similar trend was observed in the case of single ACOX1-positive peroxisomes closely adjacent to MTH, although the number of positive peroxisomes was somewhat lower, and, importantly, the increases in ACOX1-positive peroxisomes over the course of hypothyroidism were biphasic in both single ACOX1- and double ACOX1/ACOX3-positive peroxisomes (figures 3 and 4a).