Pharmacology of drugs acting on endocrine system
a. Androgens and Anabolic steroids.
b. Estrogens, progesterone and oral contraceptives.
c. Drugs acting on the uterus
a. Principles and applications of bioassay.
b.Types of bioassay
c. Bioassay of insulin, oxytocin, vasopressin, ACTH,d-tubocurarine,digitalis,
histamine and 5-HT
Hormone (Greek hormaein—to stir up) is a substance of intense biological activity that is produced by specific cells in the body and is transported through circulation to act on its target cells. Hormones regulate body functions to bring about a programmed pattern of life events and maintain homeostasis in the face of markedly variable external/internal environment.
This 14 amino acid peptide inhibits the secretion of GH, prolactin, and TSH by pituitary; insulin and glucagon by pancreas, and of almost all gastrointestinal secretions including
that of gastrin and HCl. The g.i. action produces steatorrhoea, diarrhoea, hypochlorhydria, dyspepsia and nausea as side effect. Somatostatin constricts splanchnic, hepatic and renal blood vessels. The decreased g.i. mucosal blood flow can be utilized for controlling bleeding esophageal varices and bleeding peptic ulcer, but octreotide is preffered now due to longer duration of action. Its antisecretory action is
beneficial in pancreatic, biliary or intestinal fistulae; can also be used to reduce complications after pancreatic surgery.
It also has adjuvant value in diabetic ketoacidosis (by inhibiting glucagon and GH secretion). Use of somatostatin in acromegaly is limited by its short
duration of action (t½ 2–3 min), lack of specificity for inhibiting only GH secretion and GH rebound on
discontinuation. Surgical removal of pituitary adenomas is the preferred treatment modality, but somatostatin analogues are being increasingly used.
Dose: (for upper g.i.bleeding) 250 µg slow i.v. injection over 3 min followed by 3 mg i.v. infusion over 12 hours.