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Learn about the pharmacological applications of hypothalamic and pituitary hormones, including their role in replacement therapy, drug therapy, and diagnostic testing. Discover the key hormones involved and their therapeutic uses, administration, toxicity, and contraindications.
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Pharmacological applications in : • Replacement therapy for hormone deficiency status • As drug therapy • As diagnostic tools for performing stimulation tests Hypothalamic and Pituitary Hormones
Anterior pituitary hormones include - Growth Hormone (GH) - Thyrotropin (TSH) - Follicular stimulating hormone (FSH) - Leutinizing Hormone (LH) - Prolactin - Adenocorticotropin (ACTH) Hypothalamic and Pituitary Hormones
Hypothalamic releasing hormone - Growth hormone releasing hormone (GHRH) - Gonadotropin releasing hormone (GnRH) - Thyrotropin releasing hormone (TRH) - Corticotropin releasing hormone (CRH) - Somatostatin (GHIH) - Dopamine Hypothalamic and Pituitary Hormones
GROWTH HORMONE Growth Hormone preparations: Somatropin Somatrem • Administered in a dose of 40 mg/kg per day. S.C in the evening t½ - 20 min.
Toxicity & Contraindication - GH obtained from human cadaver – CREUTZFELDT JAKOB DISEASE - Children: intracranial hypertension, vision changes, headache, nausea and vomiting. - Adults: Peripheral edema, carpal tunnel syndrome, arthralgia and myalgia. GROWTH HORMONE
GHRH • Sermorelin acelate: Synthetic form of human GHRH - Well tolerated and less expensive
Toxicity of GHRH GHRH(IV) – flushing, injection site pain, erythema, nausea, headache, metallic last, pallor, chest tightness. GHRH(SC) – pain, swelling, erythema, headache, dysphagia, dizziness, hyperactivity, somnolence, urticaria
Somatostatin (GHIH) • 14 amino acid peptide found in hypothalamus and CNS, also in pancreas and GIT. • Inhibits growth hormone release, shown to inhibit release of glucagon, insulin and gastrin • Exogenously administered SST has limited therapeutic usefulness - shorter duration of action and its multiple effects on many secretary system. • SST analogues – Octreotide, lantreotide, vapreotide
OCTREOTIDE • Synthetic derivation of SST. • 45 times more potent than SST in inhibiting growth hormone release lent only --- as potent in reducing insulin secretion – hyperglycemia rarely occurs. • Greater potency – lower clearance and longer half life t½ - 80 min. • 100 µg , s. c three times daily.
Uses • Acromegaly, carcinoid syndrome, gastrinoma, watery diarrhoea • Acute control of bleeding from esophagial varices Adverse effects • Diarrhoea, nausea, sbdominal pain, flatulance, steatorrhea with bulky bowel movements, gall stones,sinus bradycardia, conduction disturbances, vit B 12 deficiency OCTEOTIDE
PEGVISOMANT(Growth hormone receptor antagonist) • Useful in treatment of acromegaly • PEG derivative of mutant growth hormone , increased affinity for one site of GH receptor but a reduced affinity at its second binding site- allows dimerization but blocks conformational changes • Administered by s.c
GONADOTROPIN RELEASING HORMONE (GnRH) GnRH-Gonadorelin GnRH analogues- Leuprolide, Nafarelin, goserelin Administered IV, SC, IM or via nasal spray • Half life (IV)- 4 min ,other routes-3 hours • GnRH binds to receptors on pituitory gonadotrophs • Pulsatile IV administration of GnRH stimulates FSH & LH secretion • GnRH administered continuously inhibit gonadotropin release
Therapeutic uses • GnRH stimulate pituitory function- treat infertility caused by hypothalamic hypogonadotropic hypogonadism • GnRH analogues induce hypogonadism when given continuously – prostate cancer, uterine fibroid, endometriosis, PCOS GONADOTROPIN RELEASING HORMONE (GnRH)
Toxicity • Gonadorelin- headache, light headache, nausea,flushing, local swelling, dermatitis, hypersensitivity reactions • GnRH analogs- hot flushes, sweating, headache, depression, osteoporosis C/I – pregnancy and breast feeding GONADOTROPIN RELEASING HORMONE (GnRH)
CETRORELIX(GnRHANTAGONISTS) • Synthetic decapeptide • Reversibly binds to pituitory GnRh receptors without activating them , inhibits secretion of FSH & LH • Uses In vitro fertilization Endometriosis Uterine fibroids
Gonadotropins • Preparations: Menotropin Urofollitropin Follitropin • Uses Amenorhoea & infertility Hypogonadotropic hypogonadism Cryptorchism to aid in vitro fertilization
GONADOTROPINS • Adverse effects Ovarian hyperstimulation, polycystic ovary, pain in lower abdomen, ovarian bleeding, allergic reactions, edema, headache, mood changes
PROLACTIN • Principle hormone responsible fr lactation • Dopamine agonists inhibits prolactin • Bromocriptine, cabergalide, pergolide, quinagolide – lower circulatory prolactin levels and shrink pituitory prolactin secreting tumors
Uses • Prolactin secreting adenomas • Amenorrhoea, Galactorhea • Acromegaly • Parkinson’s disease Toxicity • Nausea, headche, light headness,orthostatic hypertension, fatigue, behavioral alterations, mental confusion, hallucination,psychosis