Delta Aka D Cells: secrete Somatostatin
F Cells : secrete Pancreatic Polypeptide .
Target: digestive system and blood
Functions:
Glucagon raises blood glucose levels by releasing glucose from cells. Insulin decreases blood glucose levels by stimulating cells to uptake glucose into cells for energy storage. It is most active after food intake. Somatostatin inhibits both insulin and glucagon release and slows absorption of nutrients from the GI tract. Pancreatic polypeptide inhibits somatostatin secretion and secretion of digestive enzymes by the pancreas.
Regulation:
Blood glucose levels in a negative FB system is the most important regulator of insulin and glucagon. However, several hormones and NTs also regulate the release of these two hormones. Glucagon: stimulated by decreased blood glucose levels, inhibited by insulin release. Insulin : stimulated by increased blood glucose levels. Indirectly, eGH and ACTH stimulate secretion of insulin because they act to elevate blood glucose levels. Digestion and absorption of food containing both carbohydrates and proteins provide strong stimulation for insulin release. Insulin is inhibited by decreased blood glucose levels and glucagon. Clinical Disease: Equine Metabolic Syndrome (diabetes)
Ovaries and Testes
Anatomy: The gonads have both exocrine and endocrine functions. The exocrine function is to produce ova or sperm. The paired ovaries located at the beginning of the mare’s reproductive tract within the pelvic cavity. The paired testes protected by the scrotum is located external to the body between the thighs.
Secretory Cells & Hormones:
The granulosa cells of the developing follicle produce Estrogens (estradiol & estrone) and the corpus luteum produces Progesterone . The ovaries also produce inhibin & relaxin.
The Leydig cells of the testes produce Testosterone . The testes also produce inhibin.
Target: reproductive tissues
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