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
Prothoracicotropic hormone or an abdomen under diapause would induce molting or pupation. Thus, the brain was originally thought to be the source of the hormone that induces molting in insects. Later it was established that the insect brain produces a number of hormones, but the hormone which was the cause of the observations made by Kopeć and Wigglesworth was prothoracicotropic hormone. PTTH is secreted by a neurohemal organ, the corpus cardiacum (in some insects the corpus allatum secretes PTTH) which is actually a discrete structure posterior to the brain. PTTH is released in response to environmental stimuli and as its name implies