Peptide hormone growth hormone, which acts on bone, muscle, and the liver. The posterior pituitary gland secretes antidiuretic hormone, also called vasopressin, and oxytocin. The parathyroid gland secretes parathyroid hormone, the main hormone responsible for regulating serum calcium and phosphorus levels. Peptide hormones are also produced by many different organs and tissues, including the heart (atrial-natriuretic peptide (ANP) or atrial natriuretic factor (ANF)) and pancreas (glucagon, insulin and somatostatin), the gastrointestinal tract (cholecystokinin, gastrin), and adipose tissue stores (leptin). Peptide hormone Peptide hormones or protein hormones are hormones whose molecules are peptides or proteins, respectively. The latter have longer amino acid chain
Infertility in polycystic ovary syndrome fertility, such as changed levels of gonadotropin-releasing hormone, gonadotropins (especially an increase in luteinizing hormone), hyperandrogenemia, and hyperinsulinemia. Gonadotropins are released by gonadotroph cells in pituary gland, and these cells appear to harbor insulin receptors, which are affected by elevated insulin levels. A reason that insulin sensitizers work in increasing fertility is that they lower total insulin levels in body as metabolic tissues regain sensitivity to the hormone. This reduces the overstimulation of gonadotroph cells in pituitary. PCOS usually causes infertility associated with anovulation, and therefore, the presence of ovulation indicates absence of infertility, though it does not rule out