Function: These hormones along with FSH and LH from the anterior pituitary act to:
Estrogen - regulate estrous behavior, ovulation & fertilization, secondary sex characteristics Progesterone - prepare & maintain pregnancy, prepare mammary glands for lactation Inhibin - inhibits FSH/estrogen Relaxin - aid in foaling by relaxing the ligaments of the pelvic cavity Testeosterone - descent of the testes before birth, regulation of sperm production, development and maintenance of male secondary sex characteristics
Regulation: Levels of estrogen/progesterone or estosterone in the blood control the secretion of GnRH, FSH & LH through a negative FB system.
Clinical Disease: steroid use, tumors/cysts
Pineal Gland
Anatomy: This is a small endocrine gland attached to the roof of the third ventricle of the brain at the midline. It is part of the Epithalamus.
Secretory cells: Pinealocytes .
Hormone: The pineal gland secretes Melatonin , an amine hormone derived from serotonin.
Target: brain tissue
Function : involved in the setting of the body’s biological clock. It is also thought to contribute to sleepiness. It also affects the reproductive cycle of mares & stallions.
Regulation:
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