establishes circadian rhythm
melatonin
released by alpha cells of the pancreas
released in response to high blood concentration of Ca2+
leads to glucose uptake in most tissues
leads to secretion of testosterone from testes
luteinizing hormone
calcitonin
leads to estradiol secretion from ovaries
released in response to high blood concentration of Ca2+
insulin
thyroid stimulating hormone
acts on thyroid gland follicles
glucagon
parathyroid hormone
follicle stimulating hormone
