VPT 311: General and Systemic Veterinary Pharmacology (2+1)

POSTERIOR PITUITARY HORMONES

• There are two known posterior pituitary hormones:
  • Vasopressin (ADH) and oxytocin.
  • Posterior pituitary hormones are synthesized in the hypothalamus and transported to the posterior pituitary, where they are released into circulation.

Anti diuretic hormone (Vasopresssin)

• This hormone regulates water permeability in the distal tubules and collecting duct of the nephron.
• It is also a vasoconstrictor and influences cardiovascular functions.
• It is used in the treatment of diabetes insipidus and prophylactically against bleeding in haemophilia.

Oxytocin

• Oxytocin is produced in neuronal bodies in the supra optic and paraventricular nuclei of the hypothalamus.
• Oytocin stimulates smooth muscle contractions and also includes PGF_{2 alpha} release which causes luteolysis.

Uses

• Speeding the expulsion of foetus when uterine inertia is diagnosed
• Aids in the expulsion of placental debris and promotes involution of the uterus
• In uterine prolapse injection of oxytocin at several places in the organ reduces the engorgement and contracts the everted uterus. Thus helps in the replacement more easily
• Functional agalactia in cows
• In mastitis in cattle to expel the infected milk before using any antibacterial agents.