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 signal...

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 )

Hormone	Function
CRH	Stimulates the release of ACTH
TRH	Stimulates the release of TSH
GRH	Stimulates the release of GH
GHIH	Inhibits the release of GH
GnRH	Stimulates the release of FSH & LH
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 2^nd ry sexual characteristics)

2. CRH

CRH (Hypo.T) ACTH (ant.P)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) TSH(ant.pit) Thyroxin  (thyroid)

 

 

Use to diagnose low thyroxin level as CRH

 

4.GHRH (somatotropin)

 

 

GH GH act on many tissue Increase tissue size & proteinsynthesis

Liver IGF-1(somatomedin)

 

 

 

5.Somatostatin (GHRIH)

 

 

Secretes by Hypothamus,Pancreas,Stomach,Brain

 

                                          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