Pituitary Hormones

College of DentistryQassim University

First Year

Prof. Dr. Nikhat Ahmed SiddiquiCollege of Medicine, Qumed.

(Glandular System)

Course Objectives • Name the hormones synthesized in and

secreted from Anterior and Posterior Pituitary.

• Outline the Chemical Structure and List main functions of Anterior and Posterior Pituitary.

Endocrine hormones

hormone

receptor

Secretion

Target cell

Adapted from Benjamin co

Hormone types

Often amino acid derivatives or peptides.

Steroid hormones are made from cholesterol.

Regulation of hormone

Prohormone/prehormone: precursor molecule, usually inactive and can be modified (often cut) to become active.

Preprohormone: precursor to prohormone.

Pituitary Gland

Anterior Pituitary

Hypothalamus

Hypothalamic hormones -> Anterior pituitary hormones

GHRH increases GH Somatostatin inhibits GH TRH increases TSH CRH increases ACTH PIH inhibits prolactin GnRH increases FSH and LH

So, once a certain amount of hormones are made, they shut off the system producing them!

Regulation of Anterior Pituitary

Posterior pituitary

Stores and releases 2 hormones that are produced in the hypothalamus:- Antidiuretic hormone (ADH) Vasopressin- Oxytocin

Posterior Pituitary

Hypothalamus

Connection to pituitary

Neuronal to POSTERIOR PITUITARY Endocrine to ANTERIOR PITUITARY

STIMULUS

HypothalamusReleasing Hormone

(Release-Inhibiting Hormone)

PituitaryStimulating Hormone

GlandHormone Target

Hormone Anterior Pituitary

Target Chemical Structure

Function

Adrenocortico-trophic

Hormone (ACTH)

Adrenals 39 Amino Acids

Stimulates the adrenal gland to produce hormones called: Cortisol (Glucocorticoid) Aldosterone (Miberalocorticoid)Testosterone (Androgen)Dehydroepiandrosterone sulfate (precursor of Estrogen)Cortisol promotes normal metabolism,

• maintains blood sugar levels and blood pressure. • It provides resistance to stress and acts as an inflammatory agent. •It also helps to regulate fluid balance in the body.

Thyroid stimulating hormone

(TSH)

Thyroid Glycoprotein2 polypeptide

chain(α and β)

Stimulates the Thyroid Gland to secrete its own hormone called Thyroxine (T4). It stimulates the thyroids through G-protein coupled receptors . Another hormone produced from the thyroid is called tri-iodothyronine or T3. Thyroxine controls many bodily functions, including heart rate, temperature ,growth and metabolism. It also helps metabolise calcium in the body.

Anterior Pituitary Hormone Contd;

Leutenising Hormone

(LH)

&

Follicle- Stimulating Hormone

(FSH)

Ovaries (females)

Testes (males)

Glycoprotein

2 Polypeptide Chain

(α and β)

Control reproduction and sexual characteristics. Stimulate the ovaries to produce Estrogen and Progesterone and the testes to produce Testosterone and sperm. LH and FSH are also known collectively as gonadatrophins.Estrogen helps with growth of tissue of the sex organs and reproductive parts. It strengthens bones and has a positive effect on the heart. Testosterone is responsible for the masculine characteristics including hair growth on the face and body and muscle development. It is essential for producing sperm and strengthening the bones.

Prolactin Breasts Protein198 amino acids

Stimulates the breasts to produce milk and is secreted in large amounts during pregnancy and breastfeeding.

It is however present at all times in both males and females.

Growth Hormone

(GH)

All cells in the body

Protein191 AA

In children this hormone is essential for a normal rate of growth. It stimulates the release of IGF-1 (Somatomedin).In adults it controls energy levels and well-being. It is important for maintaining muscle and bone mass and appropriate fat distribution in the body.

Hormone Posterior Pituitary

Target Chemical Nature

Function

Antidiuretic Hormone

(ADH) Vasopressin

Kidneys

Peptide 9 amino acids

Controls the blood fluid and mineral levels in the body by affecting water

retention by the kidneys ( water reabsorption).

OxytocinUterus

& Breasts

Peptide 9 amino acids

Affects the uterine contractions in childbirth and the subsequent

release of milk for breast feeding.

labor and delivery, milk ejection,(pair bonding)

• Thank you

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