Hypothalamic Pituitary Axis-Prolactin

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Endocrine system

par NA - 11MM 972639 Stephen Lewis SS

TRH neuron

par Aiman Khan

Hypothalamus

par Michael McGlue

Module 2 Mindomo Assignment

par Oanh Trinh

Milk Ejection

Uterus

Ovaries

The suckling of a newborn on a mother's breast has four effects. Firstly, it stimulates the sensory nerves, which then carry the signal from the breast to the spinal cord, where these nerves then synapse at the dorsal horn with neurons that carry the signal to the brain. Secondly, in the arcuate nucleus, the sensory afferent input from the nipple inhibits neurons that release dopamine. Dopamine normally travels via the hypothalamic-portal system to the anterior pituitary lobe, where it inhibits prolactin release from lactotrophs. Therefore, inhibition of dopamine release leads to an increase in prolactin release. Thirdly, in the supraoptic and paraventricular nuclei, the sensory afferent input from the nipple triggers the production and release of oxytocin in the posterior pituitary lobe. Fourth, in the preoptic area and arcuate nucleus, the sensory afferent input from the nipple inhibits GnRH release. GnRH normally travels via the hypothalamic-portal system to the anterior pituitary lobe, where it stimulates the synthesis and subsequent release of FSH and LH. An important note: inhibiting GnRH release inhibits FSH and LH release and thereby inhibits the ovarian cycle.

The hypothalamic portal system allows hypothalamic hormones to be transported to the anterior pituitary without first entering the systemic circulation.

Oxytocin is originally produced and released from the paraventricular and supraoptic nuclei; however, it travels down through the hypothalamic-portal system and is finally "released" from the posterior lobe of the pituitary.

Duct Proliferation & Branching

Actions stimulated by prolactin binding at PRL receptor

Prolactin is produced in the anterior pituitary gland. More specifically, lactotroph cells produce prolactin in the anterior pituitary gland where it is stored and then released into the bloodstream.

Lactogenic Enzyme Synthesis

Mammary Gland Development

Breast Differentiation

Glandular Tissue Development

Milk Production

Hypothalmic-portal system

The hypothalamic portal system allows hypothalamic hormones to be transported to the anterior pituitary without first entering the systemic circulation. 

Prolactin

Prolactin is produced in the anterior pituitary gland. More specifically, lactotroph cells produce prolactin in the anterior pituitary gland where it is stored and then released into the bloodstream.

Anterior Lobe of Pituitary

Prolactin-releasing lactotrophs

Gonadotrophs

Posterior Lobe of Pituitary

Oxytocin

Oxytocin is originally produced and released from the paraventricular and supraoptic nuclei; however, it travels down through the hypothalmic-portal system and is finally "released" from the posterior lobe of the pituitary.

HYPOTHALAMUS

Newborn baby's action of suckling begins signal transduction

Preoptic Area

Paraventricular Nucleus

Supraoptic Nucleus

Arcuate Nucleus

Spinal Cord

Lactating Mother

Breast

Hypothalamic Pituitary Axis-Prolactin