GNRH2 and hypothyroidism: In this experiment, we measured brain transcript levels of a number of neurohypothalamic peptides, including gnrh2 and gnrh3, gnih, and crf, as well as pituitary gonadotropin hormone subunits, fshb, lhb, and tshb in the methimazole-induced hypothyroidism in fish (Figure 5A,C).