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03. Hypophysiotropic hormones ( Hypothalamic Hormones )Hypothalamus & Pituitary II

Tropic hormone – stimulate hormone secretion from another gland

Secretions of pituitary gland is controlled by neural and chemical signals

  • Posterior pituitary – Neural signals
  • Anterior pituitary – Chemical signals - Hypophysiotropic hormones ( Synthesized by the hypothalamic nucleus which are carried to anterior pituitary by the portal hypophyseal blood vessels)

Hypophysiotropic hormones ( Hypothalamic Hormones )

http://www.medicallecturenotes.com/

Hormone

Function

  1. CRH

Stimulates the release of ACTH

  1. TRH

Stimulates the release of TSH

  1. GRH

Stimulates the release of GH

  1. GHIH

Inhibits the release of GH

  1. GnRH

Stimulates the release of FSH & LH

  1. PIH (Dopamine)

Inhibits the release of Prolactin

 
 

Hypothalamic Hormones

1.GnRH

  • Pulsatile secretion
  • Stimulate FSH & LH secretion
  • Use to treat infertility in females, in pulsatile manner
  • continues GnRH therapy→ receptors down regulation →↓ release of Gonadotropin →↓ Testosterone & oestrogen
    • use to treat protatic cancer:-( ↓ testosterone without doing orchidectomy)
    • use to treat precocious puberty:-(↓ Gonadotropin→ dealy 2nd ry sexual characteristics)

2. CRH

CRH (Hypo.T) clip_image001ACTH (ant.P)clip_image001[1]Cortisol (anrenal.C)

 

Low cortisol level due to problem in –

  • Ad .cortex
  • Ant.pit
  • Hypothalamus

To test it CRH is given & check the ACTH & Crtisol level rise if they rise the problem is in hypo thalamus

 

 

3.TRH

 

 

TRH (hypo.T) clip_image002TSH(ant.pit)clip_image003 Thyroxin  (thyroid)

 

 

Use to diagnose low thyroxin level as CRH

 

4.GHRH (somatotropin)

 

 

GH clip_image001[2] GH act on many tissue clip_image001[2]Increase tissue size & proteinsynthesis

clip_image005Liver clip_image006 IGF-1(somatomedin)clip_image004

 

 

 

5.Somatostatin (GHRIH)

 

 

Secretes by Hypothamus,Pancreas,Stomach,Brain

 

clip_image008

                                          Decrease  GH,Serotonin,Gastrin,VIP,Insulin

 

Ocreotide:  is an synthetic analog for GHRIH ,has a long T1/2

 

Use of octreotide & GHRIH

  • In Acromegaly
  • Carcinoid tumour secreting serotonin
  • VIPomas(VIP-secreting tumors) → cause watery diarrhea
  • Varial bleeding due to portal hypertension→ Selective vaso constriction→ Reduce portal pressure

Bromocriptine (Cause depression)

 

 

Dopamine agonist- stimulate dopamine receptors→ decrease Prolactin

Use for

I. Prolactinoma

II. Therapy of galactorrhoea[when baby is died give to mother to ↓milk ]

III. Therapy of Parkinson(due to low Dopamine )

 

  • increase  Prolactin an blood can cause amenorrhea by blocking the action of FSH/LH( gonadotropins) on ovaries
03. Hypophysiotropic hormones ( Hypothalamic Hormones )Hypothalamus & Pituitary II 03. Hypophysiotropic hormones ( Hypothalamic Hormones )Hypothalamus & Pituitary II Reviewed by Radiology Madeeasy on April 09, 2010 Rating: 5
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