Hypothalamic Pituitary Hormones Lecture NO 2 nd MBBS

Hypothalamic Pituitary Hormones Lecture NO : 2 nd MBBS Dr Muhammad Ramzan

Hypothalamic hormones - the definition • These are the hormones/factors produced by the Hypothalamic nuclei/neurons – the Neuro secretary cells • Reach anterior Pituitary through portal veins to stimulate or inhibit the release of hormones from it or 1 • Travel along the axons of Neuro secretary cells to the posterior pituitary for storage and released when required 2 • www. thefreedictionary. com

Hypothalamic Hormones – 2 types Releasing / Inhibitory and Neuro hormones • Hypothalamic hormones are of 2 types • 1. Hypothalamic Releasing (HRH) or Inhibitory hormones (HIH) for the stimulation/inhibition of Ant. Pitu. gland • 2. Neuro hormones are also produced by the hypothalamic nuclei to be stored in post. pituitary for further release

HRH or HIH – the naming for the Ant. Pitu. Hormones • HRH and HIH are produced by the hypothalamic nuclei, reach the A. Pitu. Via portal veins • They stimulate/inhibit the production of Ant. Pitu. Hormones • The hypothalamic hormones are named as HRH or HIH for the respective Ant. Pit. Hormones Like : • Hypothalamic Releasing /Inhibitory hormones for the Growth hormone (GH) are called as GHRH or GHIH • www. vivo. colostate. edu

Hypothalamic Releasing / inhibitory hormones/factor

Hypothalamic Neuro hormones from PVN and Supraoptic nuclei • • • These are synthesized in the hypothalamic nuclei - SOP+ PVN Travel along the axons of secretary neurons to be stored in Post. Pit. and are released directly into the : Circulation in response to an appropriate stimulus These are the hormones of Post. Pit. / Neuro hypophysis Like Anti diuretic hormone (ADH) and Oxytocin • www. wikepedia. com - www. britannica. com • •

Hypothalamic Neuro hormones

Neuro hormones – Difference from HRH/HIH synthesis, transport and storage • 1. Neuro hormones do not require any HRH/HIH hormones for • ( their synthesis) • 2. Travel along the axons of hypothalamic secretary cells to the Post. Pit. gland (Method of transport ) • 3. Stored there as secretary vesicles and released into blood circulation in response to a stimulus (storage)

Difference B/W Hypothalamic Stimulatory/Inhibitory hormones and Hypothalamic Neuro hormones Hypothalamic Stimulator/Inhibitory Hormones Hypothalamic Neuro. Hormones Requirement for stimulation/inhibition Require either of these for their release/inhibition Require no Hypothalamic stimulatory/ inhibitory Hormones Transportation from Hypothalamus to Pituitary Gland Are transported to Pit. Gland Via Portal veins Are transported via axons of Neuro -secretary cells Storage before their release into circulation Not stored in Pituitary Stored in Axons of Neuro – Gland, Are released directly secretary cells, Released in into systemic Circulation response to an approprpriate stimulus Parameters

HRH HIH – 5 no • • • Growth Hormone Releasing Hormone Thyrotropin Releasing Hormone Corticotropin Releasing Hormone Gonadotropin Releasing hormone Prolactin Releasing hormones - GHRH - TRH - CRH - Gn. RH - PRH 1 2 3 4 5 • (Others are Somatostatin and Dopamine , inhibit the Pit. Hor. ) • Same is true for the existence of HIH with same names • www. biology-pages. info/H/Hypothalamus - Kimball's biology

HRH /HIH – with effects on anterior pituitary hormones

Pituitary Gland – the background • Pituitary gland or Hypophysis is an endocrine gland, situated below the hypothalamus • It is enclosed in a bony cavity at the base of the skull called the Sella Turcica (Turkish saddle) • It is about the size of a pea and weighs 500 - 900 mg. • www. pituitary. org

Pituitary gland

Pituitary Gland – the Master gland Receives messages from CNS • Pituitary is also called as the Master gland, as it regulates the secretions of many glands and : • Influences the body growth, reproduction and metabolism • Pituitary Is a link B/W the hypothalamus and endocrine system and receives messages (HRH and HIH) from CNS • Thus establishing the science of Neuro endocrinology • www. pituitary. org/uk

Pituitary Gland – the divisions • • • Pituitary is divided into 2 depending upon their structure /origin Anterior Pituitary gland or Adenohypophysis Posterior Pituitary gland or Neuro hypophysis • www. pituitarysociety. org.

Pituitary Gland – the division

Hormones of Anterior Pituitary Gland 6 in no • 1. 2. 3. 4. Are 6 in Number Somatotropin /Growth hormone or GH Thyrotropin or Thyroid Stimulating Hormone or - TSH Corticotropin /Adreno corticotrophin hormone – ACTH Prolactin or PRL

Hormones of Anterior Pituitary gland – the others the Gonadotropins 5. Luteinizing Hormone or LH 6. Follicular Stimulating Hormone or FSH No 5 and 6 are collectively called as Gonadotropins Melanocyte Stimulating hormone is secreted from the middle part of the Pituitary gland www. antranik. org

Anterior pituitary hormones with effects

Types of Anterior Pituitary hormones Tropics and non tropics • Hormones from the Anterior Pituitary gland are divided into 2 on the basis of regulating the : • Growth/nutrition/functions of other endocrine glands in the body. These are called as : • Tropics and • Non Tropics

Anterior pituitary hormones - the Tropics 4 in no Tropic Hormones, the ones from anterior pituitary like : • TSH : Regulates Thyroid gland secretion • ACTH : Controls secretion of Adrenal Cortex • FSH : Promotes follicular growth and ovarian hormones • LH : Regulates testosterone from testes and spermatogenesis •

Tropic hormones - TSH

Hormones of anterior Pituitary - Non Tropics. 2 in no Non tropics are the remaining 2 of the ant. Pituitary hormones. Non tropics do not regulate activity of other endocrine glands These are the Growth hormones (GH) and Prolactin 1. Growth Hormone : Promotes Proteogenesis, cell division and body growth 2. Prolactin: Promotes lactation/ milk production after child birth Melanocyte Stimulating Hormone : regulates skin colour changes and degree of pigmentation in Melanocytes • www. wikepedia. com • • •

Hormones of Posterior Pituitary gland – 2 ADH and Oxytocin • • • The Posterior Pituitary produces 2 hormones : Vasopressin /Ant diuretic hormone (ADH) and Oxytocin. ADH : maintains water/fluid /electrolyte balance and BP 1 Oxytocin : stimulates the contraction of : smooth muscles of the uterus; Myoepithelial cells of ducts of mammary glands and vas deferens 2

Posterior pituitary hormones with effects