Hypothalamus and Pituitary

Pituitary originates from Latin and Greek, meaning

Spit mucus

It is originally thought to secrete mucus, it was later identified as the master gland that regulates other endocrine glands through hormone selection

Pituitary Gland

Anatomy of Pituitary Gland consists of three parts

_______________ - Responsible for most hormone production

_______________ - Poorly developed in humans, may form benign cystic enlargements

_______________ - Stores and releases oxytocin and AVP (Formerly ADH)

Anterior Pituitary

Intermediate Lobe

Posterior Pituitary

The pituitary gland is connected to the hypothalamus via the ______________, which contains neural and vascular structures

Pituitary Stalk

The anterior pituitary receives most of its blood supply through the ___________________

hypothalamic-hypophyseal portal system

Many pituitary hormones show ___________ variation, regulated by external cues like light and darkness

Diurnal Variation / Circadian Variation

Pituitary Enlargement occurs during puberty and pregnancy due to ______________, which can occur in primary thyroid or gonadal failure

Lactotroph hyperplasia

Hormones located at the Anterior Pituitary Hormone

Growth Hormone

Prolactin

2 types of Anterior pituitary hormones

_______________ - Acts on other endocrine glands

_______________ - Act directly on peripheral tissues

Tropic Hormones

Direct Effectors

Tropic Hormones

______________ - Ovulation and Testosterone production

______________ - Ovarian recruitment and folliculogenesis, spermatogenesis

______________ - Stimulates thyroid hormone

______________ - Regulates adrenal steroidogenesis

Luteinizing Hormone (LH)

Follicle-stimulating hormone (FSH)

Thyroid-Stimulating Hormone (TSH)

Adrenocorticotropic Hormone (ACTH)

Direct Effectors

__________________ - Regulates growth and metabolism

__________________ - Involved in lactation and other functions

Growth Hormone

Prolactin

Hormone essential for normal growth. It is amphibolic, which contributes to both catabolism and anabolism. It works with other hormones and requires good nutrition, insulin, and health for optimal function

Growth Hormone

Structure and Regulation of Growth Hormone

______________ - Stimulates release

______________ - inhibits release

______________ - potent stimulator

Growth Hormone Releasing Hormone

Somatostatin

Ghrelin

Actions of GH

_________________ - Opposes insulin action on glucose metabolism, it stimulates hepatic gluconeogenesis and lipolysis

_________________ _ Enhances protein synthesis and nitrogen balance, stimulates liver to produce IGF-1

Catabolic Effects

Anabolic Effects

Suppression and stimulation test for GH

_________________: Used to diagnoses acromegaly
_________________: Used to diagnose GH deficiency

Glucose Suppression Test

Stimulation Test

GH disorder

_________________ - Excessive linear growth due to excess GH before plate closure in childhood

_________________ - Abnormal bone and soft tissue enlargement caused by excess GH in adulthood

Gigantism

Acromegaly

Hormone Related to Growth Hormone and human placental lactogen, classified as direct effector hormone

Prolactin

Prolactin is primarily inhibited by

Dopamine

Most common functional pituitary tumor

Prolactinoma

Prolactin levels that suggests prolactinoma

>150 ng/mL

Therapy for Prolactinoma used for aggressive tumors resistant to other treatments

Radiation Therapy

Effects of Hyperprolactinemia:

_____________ - It leads to hypogonadism, infertility, and menstrual irregularities

_____________ - Breastmilk production in non-lactating individuals

Inhibits Gonadotropin

Galactorrhea

Presence of a biologically inactive large PRL molecule causing hyperprolactinemia but minimal symptomos

Macroprolactinemia

Loss of anterior functions due to pituitary or hypothalamic failure

Hypopituitarism

Type of Hypopituitarism

___________________ - Complete loss of all anterior pituitary hormones

___________________ - Loss of a single hormone

Panhypopituitarism

Monotropic Hormone Deficiency

Cause of Monotropic Hormone Deficiency that is caused by severe blood loss during childbirth

Postpartum ischemic necrosis / Sheehan Syndrome

Congenital / Genetic disorder due to deficiency of GnRH

Kallmann’s syndrome

Recommended Treatment for Monotropic Hormone Deficiency

Hormone Replacement Therapy

Hormones of the Posterior pituitary

Oxytocin

Arginine Vasopressin

Hormone that stimulates uterine contractions during labor, induces milk ejection during breastfeeding

Oxytocin

_______________ - Regulation mechanism of Oxytocin where uterine contractions trigger more oxytocin release

_______________ - Synthetic oxytocin that induces laboro

Positive Feedback Mechanism

Pitocin

Hormone that regulates water balance by promoting kidney water retention

Arginine Vasopressin

Receptors of AVP

V2 (______): Insert Aquaporins for water reabsorption

V1 (______): Increases blood pressure

Kidney

Blood pressure

Condition due to deficiency of AVP, excessive urination and thirst

Diabetes INsipidus

It regulates anterior and piruitary function, these hormones exist outside the hypothalamus, but their functions in other tissues remain unclear

Hypophysiotropic Hormones

Hypophysiotropic Hormones:

______________ - Releases TSH and PRL

______________ - Releases LH and FSH

______________ - Releases ACTH

______________ - Inhibits GH and TSH release

______________ - Inhibits PRL

Thyroid releasing hormone

Gonadotropin Releasing Hormone

Corticotropin Releasing Hormone

Somatostatin

Dopamine