Endocrine LAqs and SAqs

These notes have been compiled from past examination papers in Biochemical Endocrinology. Wishing you an insightful and productive study session. . 1. DDT (dichlorophenyl trichloroethane) 2. Bisphenol A (BPA) 3. PCBs (polychlorinated biphenyl compounds) 4. Pesticides 5. Nonylphenols **Adjuvant therapy** – is when hormones are used with other therapies in cancer treatment to reduce side effects. - **Example: **Aromatase inhibitors + Tamoxifen the estrogen receptor antagonist used for treating breast cancer in menopausal women. - The goal of adjuvant therapy for breast cancer is to prevent the recurrence of the disease by eradicating micrometastatic disease. Features of Autacoids 1. Not released or stored in glands 2. Not circulated in blood 3. Have very short *half-life (****t******1/2 ****)* 4. Are formed at the site of action 5. Produce localized action **hCG is secreted by trophoblast cells** of the developing placenta shortly after fertilization and implantation. It enters the **maternal bloodstream and urine** within 6–12 days post-conception. The test uses **monoclonal antibodies specific to the β-subunit** of hCG to ensure specificity (avoiding LH cross-reactivity). A **sandwich ELISA or immunochromatographic method** is used to detect hCG levels. A **positive test line** appears when hCG binds to the antibodies, confirming pregnancy. - **Bone Turnover:***Paget’s disease:* Characterized by **increased and disorganized bone remodeling**. - *Osteoporosis:* Involves **decreased bone mass and increased resorption**, with normal remodeling pattern. - **Bone Structure:***Paget’s disease:* Bones become **enlarged, deformed, and structurally weak**. - *Osteoporosis:* Bones are **porous, thinned, and brittle** due to loss of density. - **Biochemical Markers:***Paget’s disease:* Often shows **elevated alkaline phosphatase (ALP)** due to increased osteoblastic activity. - *Osteoporosis:* **Normal ALP**, unless fracture or other condition is present. - **Commonly Affected Sites:***Paget’s disease:* Affects **skull, pelvis, femur, and spine**. - *Osteoporosis:* Common in **vertebrae, hip (femoral neck), and wrist**. **A. Biosynthesis of Catecholamines:** - **Tyrosine** (from phenylalanine) is the precursor. - **Step 1:** Tyrosine → DOPA via *tyrosine hydroxylase*. - **Step 2:** DOPA → Dopamine via *DOPA decarboxylase*. - **Step 3:** Dopamine → Norepinephrine via *dopamine β-hydroxylase*. - **Step 4:** Norepinephrine → Epinephrine via *phenylethanolamine N-methyltransferase* (in adrenal medulla). - Stored in vesicles, released upon stimulation. **B. Role in Human Behavior:** - **Dopamine:** Reward, motivation, mood regulation, addiction, motor control (Parkinson’s, schizophrenia). - **Norepinephrine:** Alertness, attention, arousal, stress response. - **Epinephrine:** Fight-or-flight, enhances fear, anxiety, and performance. - Clinical implications: ADHD, mood disorders, substance abuse. - **GABA-A (ionotropic):** Ligand-gated chloride channels → hyperpolarization → inhibition. Targeted by **benzodiazepines, barbiturates, alcohol**. - **GABA-B (metabotropic):** G-protein coupled → opens K⁺ channels and inhibits Ca²⁺ channels. Affected by **baclofen**. - Both reduce neuronal excitability, contributing to inhibitory neurotransmission. **Importance:** - Produces **cortisol**, **aldosterone**, **androgens** (cortex), and **epinephrine**, **norepinephrine** (medulla). - Regulates stress response, blood pressure, metabolism, and electrolyte balance. **Disorders:** - **Cushing’s Syndrome:** Excess cortisol (hypertension, obesity). - **Addison’s Disease:** Cortisol/aldosterone deficiency (fatigue, hypotension). - **Congenital Adrenal Hyperplasia:** Enzyme defects → androgen excess. - **Pheochromocytoma:** Catecholamine-secreting tumor (sweating, palpitations). **Hypothalamic Hormones:** - **TRH**: Stimulates TSH and prolactin. - **CRH**: Stimulates ACTH. - **GnRH**: Stimulates LH and FSH. - **GHRH**: Stimulates GH. - **Somatostatin**: Inhibits GH and TSH. - **Dopamine**: Inhibits prolactin. **Pituitary Hormones:** - **Anterior Pituitary:****TSH**: Thyroid stimulation. - **ACTH**: Stimulates adrenal cortex. - **GH**: Growth, metabolism. - **PRL**: Lactation. - **FSH/LH**: Reproduction. - **Posterior Pituitary:****ADH**: Water retention. - **Oxytocin**: Uterine contractions, milk ejection. **Clinical Relevance:** - Disorders: Acromegaly, hypopituitarism, SIADH, diabetes insipidus, prolactinoma. - **Inhibits Desire:** High serotonin levels can reduce sexual desire and arousal. - **Sexual Dysfunction:** Low serotonin is linked to issues like premature ejaculation and erectile dysfunction. - **Orgasm Regulation:** Serotonin can delay orgasm and influence sexual response. - **SSRIs:** Antidepressants (SSRIs) affect serotonin, often causing sexual side effects. - **Sensory Neurons:** Transmit sensory information to the CNS (e.g., pain, touch). -