GHRH and pseudohypoparathyroidism type 1A: Thus, maternally inherited mutations cause, in addition to AHO features, resistance to parathyroid hormone (PTH) and other peptide hormones that mediate their action through G protein coupled signaling pathways, such as thyroid-stimulating hormone (TSH), growth hormone-releasing hormone (GHRH), and gonadotropin-releasing hormone (GnRH).