HYPOTHAMUS-PITUITARY CONTROL SYSTEM

Pituitary is the proximal endocrine gland which links the Central Nervous System for NEUROENDOCRINE control of both metabolism and reproduction. These NEUROHORMONES control synthesis and secretion of Anterior Pituitary hormones which control Thyroid, Adrenal, Gonads, Growth & Lactation.

REGULATION OF ANT PITUITARY CELL FUNCTION BY HYPOTHALAMIC NEUROHORMONES

NEUROHORMONES are synthesized in specialized neurosecretory cells which are concentrated within Hypothalamus. Neurohormones reach Anterior Pituitary Gland via a specialized portal vascular system. Nerve fibers originating in neurosecretory cells terminate in the MEDIAN EMINENCE of the hypothalamus located below third ventricle.

Anterior Pituitary Hormones secreted (PEPTIDES) –>

  1. Adrenocorticotropin (ACTH)
  2. Follicle Stimulating Hormone (FSH)
  3. Luteinizing Hormone (LH)
  4. Thyroid Stimulating Hormone (TSH)
  5. Growth Hormone (GH)
  6. Prolactin
NEUROHORMONEPITUITARY SITE OF ACTIONEFFECTEXTRAHYPOTHALAMIC SYNTHESISEXTRAPITUITARY EFFECTS
THYROTROPIN RELEASING HORMONE (TRH)Thyrotroph  ProlactotrophStimulate StimulateBrain and Gastrointestinal TractYES
GROWTH HORMONE RELEASING HORMONE (GRH)SomatotrophStimulatePancreasYES
SOMATOSTATIN (SS)Somatotroph ThyrotrophInhibit      InhibitBrain, Pancreas and Gastrointestinal TractYES
GONADOTROPIN-RELEASING HORMONE (GnRH)GonadotrophStimulateGonadsYES
CORTICOTROPIN-RELEASING HORMONE (CRH)CorticotrophStimulatePancreasYES
PROLACTIN-INHIBITING HORMONE (PIH)ProlactotrophInhibitGonads 
DOPAMINEProlactotrophInhibitAdrenal medulla and Nervous systemYES
NEUROHORMONES

Regulation of most anterior Pituitary function depends primarily on positive stimulatory signals from hypothalamus EXCEPT biogenic amine dopamine and PROLACTIN INHIBITING HORMONE.

ANTERIOR LOBE OF PITUITARY –> connected to hypothalamus via HYPOPHYSEAL PORTAL VASCULAR SYSTEM.

POSTERIOR LOBE OF PITUITARY –> Is an elongated extension of the ventral hypothalamus. (Supraoptic and paraventricular nuclei)

Posterior Pituitary hormones (PEPTIDES)–>

  1. Antidiuretic Hormones (ADH) / Vasopressin
  2. Oxytocin

Although ADH and Oxytocin are synthesized in discrete cells, producer cells for each hormone are located in both supraoptic and paraventricular nuclei areas. Each peptide is synthesized as part of a larger precursor protein and after processing remains noncovalently bound to a portion of the precursor termed NEUROPHYSIN.

NEUROHORMONES OUTSIDE THE HYPOTHALAMUS

Neurohormones initially identified in the hypothalamus by their effects on anterior Pituitary function are also synthesized in several locations throughout the body, esp

  1. Within Gastrointestinal tract
  2. Other central nervous system areas

“YOU NEED SELF-CONTROL IN OUT OF CONTROL WORLD” – James C Collins

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: