Lect 20

• A hormone is a chemical that is produced and secreted by an endocrine gland to regulate physiological functions.
• The general characteristics and functions of hormones include sending chemical signals to everywhere in the body, playing a role in the development of bones and muscles, being necessary for bodily changes such as puberty, controlling metabolism, and aiding in the upkeep of homeostasis.
• Hormones control the functions of all the organs and affect diverse processes of growth, development, reproduction, and sexual characteristics, temperature, hunger.
• Types of hormonal imbalances in animals include hypersecretion, hyposecretion, and ectopic secretion.
• The structure-based classification of hormones includes steroids, amines, peptides/proteins, and cholesterol.
• Ketoconazole blocks production of adrenal steroids and is used to treat hyperadrenocorticism in dogs that are resistant to mitotane and as palliative therapy in dogs with cancer metastasis.
• Mitotane (Lysodren R) is an irreversible corticosteroid inhibitor used for Cushing’s syndrome and adrenal neoplasms.
• Trilostane (Modrenal R) is a synthetic steroid analog used in dogs for treatment of Cushing’s syndrome.
• Deoxycorticosterone pivalate suspension and fludrocortisone are used for replacement therapy for hypoadrenocorticism (Addison’s disease).
• Adrenal steroid inhibitors are used to control hyperadrenocorticism (Cushing’s disease or adrenal gland carcinoma).
• ACTH secretion leads to muscle wasting, osteoporosis, fat redistribution into the face, trunk, back, red and swollen skin, diabetes risk, acne, hair loss, increased platelets, GI ulceration, and can resemble Addison’s disease.
• Endocrine drugs can be classified based on their mechanism of action, target, and function.
• Adverse effects of ne excretion include GI symptoms such as vomiting and diarrhea, and CNS symptoms such as restlessness, repetitive movements, or lethargy; salivation, anorexia, and diminished hearing/deafness.
• Adrenal Steroid Inhibitors are a type of medication used to treat ne excretion.
• Pituitary gland hormones include ACTH (Corticotrophin), TSH (thyrotropin), LH & FSH (gonadotrophins), and PRL (prolactin).
• Pituitary disorders in dogs and cats include hypopituitarism, hyperpituitarism, and hypophysitis.
• Growth hormone (GH) signaling involves the GH receptor, GH-binding protein, and GH-activating enzyme.
• Growth hormone agents include somatropin, sermorelin, and CJC-1295.
• Adrenal glands produce corticosteroids, including glucocorticoids and mineralocorticoids.
• Adrenal dysfunction can be caused by diseases such as Cushing's disease and Addison's disease.
• The mechanism of action of corticosteroids involves the glucocorticoid receptor.
• Corticosteroids can be classified based on their duration of action, physiological and pharmacological effects, adverse effects, and corticosteroid therapy.
• The endocrine system encompasses a group of organs/glands that release hormones into circulation for regulating various physiological functions.
• Hormones and neurotransmitters regulate each other in a feedback system.
• Neurohormones include Noradrenalin, Dopamine, Oxytocin, and others.
• Endocrine System, Glands, and Hormones regulate pituitary function in diabetes.
• Functions of hormones include sending chemical signals to everywhere in the body, playing a role in the development of bones and muscles, being necessary for bodily changes such as puberty, controlling metabolism, and aiding in the upkeep of homeostasis.
• Hormones can be classified based on their target, function, and origin.
• Endocrine system disorders can lead to diabetes, hypothyroidism, hypopituitarism, hyperpituitarism, and hypophysitis.
• Hormone replacement therapy is used to treat hormone deficiencies.
• Cortisol also plays a part in regulation of fluid balance in the body.
• FSH: follicle stimulating hormone
• Oxytocin affects uterine contractions in pregnancy and birth and subsequent release of breast milk.
• ACTH: stimulates adrenal glands to produce corticosteroids
• GH: stimulates growth and repair
• ACTH: adrenocorticotropic hormone
• Thyroxine also plays a role in the metabolism of calcium in the body.
• Drugs that produce hormone-like effects have important therapeutic value for the treatment of endocrine hypo-function.
• Drugs that inhibit the hormone synthesis or block receptors can be used for the treatment of endocrine hyper-function.
• LH: luteinizing hormone