ANTERIOR PITUITARY HORMONES 15TH MARCH 2014 _2

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Dr. RAGHU PRASADA M S MBBS,MD ASSISTANT PROFESSOR DEPT. OF PHARMACOLOGY SSIMS & RC. :

Dr. RAGHU PRASADA M S MBBS,MD ASSISTANT PROFESSOR DEPT. OF PHARMACOLOGY SSIMS & RC. ANTERIOR PITUITARY HORMONES

Regulation of anterior pituitary function:

Regulation of anterior pituitary function Hormones are chemical substances which are synthesized by specific endogenous glands and secreted internally, directly into the blood stream, to act far away from the site of their production and release on the specific target organs. Ex- TSH Tropic hormones -- target other endocrine glands to release their own hormones. Ex TRH

Hypophysiotropic Hormones:

Hypophysiotropic hormones (Neuro-secretions) into the hypothalamo-hypophyseal portal system— Include TRH, GnRH These hormones are clustered in discrete hypothalamic nuclei Hypothalamic hormones travel in portal system from hypothalamus to anterior pituitary Hypothalamic hormones regulate hormones secretion by anterior pituitary Hypophysiotropic Hormones

Hypothalamopituitary axis:

Hypothalamopituitary axis Hypothalamic releasing factors Somatotrophs Lactotrophs Gonadotrophs Luteinizing hormone corticotrophs

Regulation of anterior pituitary function:

Regulation of anterior pituitary function Primarily by the CNS– All pituitary hormones except PRL would decline in the absence of the hypothalamus By hormones produced in peripheral target glands Example– inhibin secreted from gonads All anterior pituitary hormones secreted in a diurnal pattern.

Regulation of anterior pituitary function:

Regulation of anterior pituitary function Short negetive feed back Long negetive feed back

PowerPoint Presentation:

1. 3. 2. hormonal families of the anterior lobe :

Glycoprotein hormone family– TSH, FSH, LH:

Glycoprotein hormone family– TSH, FSH, LH TSH– to stimulate the secretion of thyroid hormone FSH & LH– important for the function of the testes and the ovaries FSH– growth of ovarian follicles and formation of sperm LH (in women)– induce ovulation and the formation of the corpus luteum; stimulate the ovarian production of estrogen and progesterone LH (in men)– stimulates the production of Testosterone

Anterior Pituitary or Adenohypophysis:

Anterior Pituitary or Adenohypophysis Hypo-secretion: During childhood causes Dwarfism Hyper-secretion: During childhood causes Gigantism (up to 8 – 9 ft.) During Adulthood causes Acromegaly: Enlargement of the small bones of the hand and feet Enlargement of the cranium, nose, and lower jaw Tongue, liver, and kidneys become enlarged

Control of GH secretion:

Control of GH secretion By both Growth hormone releasing hormone (GHRH; from arcuate nuclei mainly); its gene is expressed in the GI tract and the pancreas and by somatostatin (Growth hormone release inhibiting hormone) (from preoptic periventricular and paraventricular nuclei); its gene is expressed in GI tract and the pancreas Ghrelin (a peptide from the Arcuate Nuclei) also increase GH secretion via GHRH Ghrelin is also synthesized in the stomach and is thought to signal feeding behavior

Growth hormone analogues and GHRIH:

Growth hormone analogues and GHRIH SERMORELIN -Synthetic analogue of GnRH SOMATOSTATIN-GHRIH OCTREOTIDE -long acting analogue of somatostatin Dose-20-200mg sc TDS -carcinoid syndrome Bleeding oesophageal varices Treatment of AIDS associated diarrhoea Insulinomas SANDOSTATIN -slow release formulation ADR- steatorrrhoea , gall stones

LANREOTIDE:

LANREOTIDE GHRIH -thyroid tumours Acromegaly PEGVISOMANT- sc New GH-receptor antagonist-acromegaly Suppress IGF-1 levels -allows dimerisation and blocks the ongoing conformational changes Demerit- formation of antibodies

Pharmacological actions:

Pharmacological actions Protein synthesis Anabolic effects Somatomedins –IGF1, IGF2 Metabolic consequence  insulin like effect antagonistic to ILEeffect antagonistic to insulin IGF1-released from liverpositive feedback on hypothalamusGHRIH Increase-GH- sleep, exercise Decrease-L-dopa

Somatotropin:

Somatotropin -t1/2-25 min Sc-0.2mg/kg AIDS Burn injuries Ant aging ADR-insulin resistance Arthralgia

MECASERMIN:

MECASERMIN Recombinant human IGF1+ recombinant human IGFBP-3 Maintain desired t1/2 of IGF -short statured children Dose-0.04-0.08 mg/kg ADR-hypoglycemia

Gonadotropins :

Gonadotropins GnRH- LH FSH-inhibin, activin FSH in females, LH in females Feed back Gonadorelin- synthetic

GnRH agonists:

GnRH agonists Leuprolide Nafarelin Buserelin Dosrelin Goserelin Triptorelin

GnRH antagonist :

GnRH antagonist Cetrorelix Ganirelix Abarelix Degarelix Uses - advanced prostate ca Uterine fibroids and endometriosis IVF

Natural gonadotropins:

Natural gonadotropins From post menopausal women Menotropin Urofollitropin Recombinant FSH HCG USES -infertility Cryptorchism IVF Kaposi sarcoma Diagnostic use

Adrenocorticotropin family:

Adrenocorticotropin family ACTH (adrenal corticotropic hormone) regulates hormone secretion by the cortex of the adrenal glands. ACTH- stimulates –Glucocorticoids, mineralocorticoid and androgens ACTH-stimulated by trauma and stress Melanocytes and keratinocytes pigmentation by MSH (Melanotrope in arcuate neurons)– food intake

Adrenocorticotropin family:

Adrenocorticotropin family Hypo-secretion Addison’s disease – Simmond’s disease, hypo pituitary cachexia Hyper-secretion: Cushing’s Syndrome mobilization of fat from lower body to the thoracic and upper abdominal regions giving raise to “Buffalo Torso”

COSYNTROPIN:

COSYNTROPIN Is a synthetic human ACTH Diagnosis of pituitary adrenal axis ADR- similar to corticosteroids Allergic reactions

Prolactin :

Prolactin Peptide hormone PRIH-PRL release inhibitory hormone-D2 Stimulus for prolactin-suckling mammotropic and lactogenic Hyperprolactinemia-galactorrhoea, amenorrhea , infertility

Treatment of hyperprolactinemia:

Treatment of hyperprolactinemia Bromocriptine -2.5mg orally-15days Cabergoline-0.25mg orally -BD Pergolide- Quinagolide-0.2-0.6mg/day

Posterior Pituitary Hormones:

OT (oxytocin) and ADH produced in hypothalamus transported by hypothalamo-hypophyseal tract to posterior lobe (stores/releases hormones) Posterior Pituitary Hormones

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