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PHG 413 Hormones

PHG 413 Hormones. Dr. Areej M. Al-Taweel Pharmacognosy Department. Chemical Classification of Hormones. A- Steroidal Hormones: 1- Adrenocorticoids: Glucocorticoids e.g. Hydrocortisone. Mineralocorticoids e.g. Aldosterone. 2- Sex Hormones:

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PHG 413 Hormones

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  1. PHG 413 Hormones Dr. Areej M. Al-Taweel Pharmacognosy Department

  2. Chemical Classification of Hormones A- Steroidal Hormones: 1- Adrenocorticoids: Glucocorticoids e.g. Hydrocortisone. Mineralocorticoids e.g. Aldosterone. 2- Sex Hormones: Female sex hormones e.g. Estrogens and Progestins Male sex hormones e.g. Androgens.

  3. B- Amino acids derived hormones: 1- Hormones derived from single amino acid e.g. Thyroxin. 2- Peptide hormones: i- Only amino acids: *Anterior Pituitary hormones: - Prolactin - Growth Hormone - Placental lactogen. * Corticotropins:Adrenocorticotropic hormone ACTH. * Insulin * Parathyroid hormone and Calcitonin. ii- Glycoproteins (Amino acids and sugars): *Anterior Pituitary Hormones: - Leuteinizing hormone (LH) -Follicle Stimulating hormone (FSH) - Chorionic Gonadotropin (CG) -Thyroid Stimulating hormone (TSH).

  4. Mechanisms of Hormonal Actions

  5. I- Peptide Hormones • Peptide hormones do not enter the cell but bind to plasma membrane receptors. ■ Peptide hormones combine with membrane receptors that activate signal transduction. ■Many hormones use a G protein-linked- adenylyl cyclase-cAMP second messenger. • Second messengers activate other intracellular chemicals to produce the target cell response.

  6. II-Steroid Hormones ■ Once inside the cell the steroid hormone binds with a specific receptor found only in the cytoplasm of the target cell. The receptor bound steroid hormone then travels into the nucleus. • The activated hormone-receptor complex binds to DNA and initiates transcription of a particular gene. The result is production of messenger RNA followed by protein synthesis. (new protein produce change in cellular activity)

  7. Thyroid Hormones

  8. Thyroid Gland: • Highly vascular flat structure. • Located at the upper portion of the trachea. • Composed of twp lobes.

  9. Hormones of the Thyroid gland: • Thyroid gland secretes Thyroxin T4 and lesser amounts of triiodothyronine (T3). • Calcitonin. Thyroxin and Tiiodothyronin * Structures: Derived from single amino acid.

  10. Structure Activity Relationship • Angle between the two aromatic rings must be 1200. • 3’-Monosubstituted molecules are more active than 3’, 5’-disubstituted ones. • Triiodothyronin is 4 times more active than Thyroxin. • 3’-Isopropyl derivative is 7 times more active than Thyroxin.

  11. Regulation:

  12. Stimulation: TRH Inhibition: -ve Feed-back mechanism. When blood concentrations of thyroid hormones increase above a certain threshold, TRH-secreting neurons in the hypothalamus are inhibited and stop secreting TRH.

  13. Actions of the Thyroid Hormones: • Enhance growth and protein synthesis. • Essential for the development of the nervous system. • Increase oxygen consumption and basal metabolic rate. • Increase body temperature. • Cardiovascular effect: • Increase heart rate. • Increase force of contraction. • Increase cardiac output.

  14. Disordersof thyroid function include: • * Hypothyrodisim • - In infants, cretinism • - In adults this cause myxoedema • * Hyperthyrodisim either: • - Diffuse toxic goiter • - Toxic nodular goiter

  15. Disorders of thyroid functionHypothyroidism in children (Cretinism) Cretinism: • Irreversible condition due to deficiency of thyroxin soon after birth. • Retardation in physical and mental development.

  16. Sign and symptoms of Cretinism: - Mental retardation - Large head - Swollen eye lids - Flattened nose - Temperature below normal - Enlarged tongue - Grows very slowly. - Poor metabolism - Thick, dry, cool skin

  17. Disorders of thyroid function • Hypothyroidism (Adult) Myxoedema: • Deficiency of thyroxin in adults due to: • Removal of thyroid gland by surgery. • Destruction of the gland by Radioactive Iodine. • Atrophy of the thyroid gland.

  18. Symptoms of Myxedema: • Muscle weakness. • Slow heart rate and low cardiac output. • Dry cold and thick skin. • Brittle coarse hair. • Puffy expressionless face. • Decreased sweating • Increase body weight and body fat Treatment: • Thyroxin for life. • eg. :L-Thyroxin sodium • (Synthyroid)

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