Lecture 4: Hormones

Two regions of a catalytic receptor:

receptor region on ECF side;
enzyme region on ICF side.

Catalytic receptors often form __________ to be active.

dimers.

For catalytic receptors, the ligand is:

not lipid-soluble.

For catalytic receptors, __________ of the effector to the nucleus is required.

translocation.

Kinase that phosphorylates transcription factors:

PKA.

In the JAK/STAT catalytic pathway, activation of __________ leads to phosphorylation of transcription factor.

TKAR.

__________ receptors are unbound receptors found in cytosol or nucleus.

nuclear.

Ligand for nuclear receptor is:

lipid-soluble.

Ligand-nuclear receptor complex acts as a __________ __________.

transcription factor.

Ligand-nuclear receptor complex results in gene activation or inactivation, and thus __________ protein synthesis.

de novo (AKA genomic effect).

Nuclear receptor pathways have a __________ lag time between binding and response.

long.

Ligands for nuclear receptors are typically:

steroid or thyroid hormone (TH, an amine).

__________ are a chemical secreted by a cell or group of cells into the blood for transport to a distant target.

hormones.

Hormones exert their effects at very __________ concentrations.

low.

The endocrine system groups structures that, although may be unrelated, all use the same long-distance __________ pathway using hormones.

signalling.

Hormones are primarily secreted by __________.

glands.

Glands are tissues derived from __________.

epithelium.

Although mostly secreted by glands, some gormones are secreted by individual __________, __________, and __________ system.

cells, neurons (neurohormones), and immune system (cytokines).

Hormones can act locally (__________).

paracrine.

Hormones can act at a distance, depending on the location of the __________ cells.

target.

Hormones can be classified by __________ __________, which is the most practical classification method due to the implications of receptor type and secretion/storage.

water solubility.

Hormones can be classified by the source of __________.

secretion.

Hormones can be classified by its mechanism of action, AKA the type of __________ used.

receptor.

Hormones can be classified by __________ classes.

chemical (peptide, steroid, amine).

Peptide hormones are synthesized as large __________ proteins in the ER.

precursor (preprohormones).

Peptide hormones are processes in the Golgi into a second stage __________ form.

inactive (prohormone).

Peptide hormones are packaged into secretory vesicles and processed (post-translational modification) into the __________ form.

active (hormone).

After being packaged and processed, protein hormones are stored until __________ to be released.

signaled.

Peptide hormones are able to be stored in vesicles because they are:

water soluble (trapped).

Secretion of vesicular contents (peptide hormone + peptide fragments) by __________ into the bloodstream.

exocytosis.

Peptide hormones are water-soluble and thus dissolve easily into the __________.

ECF.

Peptide hormones have __________ half-lives.

short.

Protein hormones are lipophilic and thus must bind a cell surface __________ and usually act through a __________ messenger system.

receptor; second.

Protein hormones have a __________ lag time between binding and response.

short.

Stored cholesterol undergoes a series of enzymatic reactions that modify the basic cholesterol molecule in the __________ ER.

smooth.

The enzymes that produce specific hormones are only present in __________ steroidogenic cells.

specialized.

Specialized steroidogenic organs may only produce specific __________.

steroids.

Once synthesized, lipophilic __________ diffuse through the plasma membrane and enter the blood.

steroids.

Steroid hormones are not water-soluble, thus must be bound by a __________ __________.

carrier molecule (specific or non-specific).

Non-specific carriers of steroid hormones are:

albumin.

Steroid hormones binding to the carrier molecule extends the __________ but blocks the entry of the steroid into cells.

half-life.

Dynamic __________ between bound and unbound hormone obeys the law of mass action to maintain the ratio so that the plasma membrane stays constant.

balance.

Steroid hormones bind to intracellular receptors located in the __________ or __________.

cytosol or nucleus.

Steroid hormones bind to intracellular receptors which act as __________ __________.

transcription factors.

Steroid binding to intracellular receptors results in __________ __________.

gene activation/inactivation.

Steroid binding to intracellular receptors results in de novo protein synthesis, AKA __________ __________.

genomic effect.

Amine hormones are derived from the amino acid __________ or __________.

tyrosine or tryptophan.

Melatonin is an example of:

tryptophan amine hormone.

Catecholamines and thyroid hormones are examples of:

tyrosine amine hormone.

__________ act like peptide hormones and bind to cell surface receptors and work through second messengers.

catecholamines.

__________ hormone acts like steroid hormones and bind intracellular receptors and activate gene transcription.

thyroid.

A single endocrine gland may produce:

more than one hormone.

Anterior pituitary produces:

6 different hormones.

A single hormone may be secreted by:

more than one endocrine gland.

Somatostatin is released by both:

hypothalamus and pancreas.

A single hormone can have more than one type of:

target cell.

__________ can act on muscles, liver, fat, and other tissues.

insulin.

Rate of secretion of some hormones varies considerably over the course of time in a __________ pattern.

cyclic (ex. circadian, menstrual, etc).

A single target cell may be influenced by __________, often with opposing effects,

more than one hormone.

Insulin and glucagon both act oppositional on __________ cells.

hepatic.

Progesterone and estrogen both act oppositional on __________ cells.

uterine.

A chemical messenger may be either a __________ or __________ depending on its source and method of delivery.

hormone or neurotransmitter.

__________ is secreted to the blood by adrenal medulla (hormone) and locally by sympathetic postganglionic fibers (neurotransmitter).

NorE.

Some __________ are exclusively endocrine while others perform non-endocrine functions.

organs.

Permissiveness describes the effect of a hormone being dependent on the prescience or activity of:

a second hormone.

Thyroid hormone promotes reproductive development by the __________ and s@x steroids.

gonadotropins.

Synergism describes __________ hormones; the sum of the combine effects is greater than the sum of individual effects.

complementary.

Epi and glucagon display __________.

synergism (Epi ↑ blood glucose, Glucagon ↑ blood glucose, Epi & Glucagon ↑↑↑ blood glucose).

Antagonism describes the effect of one hormone resulting in the loss of another hormone’s __________.

receptors.

Progesterone (decreases uterine contractions) inhibits uterine responsiveness to __________.

estrogen.

The pituitary gland has two __________ and __________ distinct lobes.

anatomically and functionally.

__________ pituitary is glandular.

anterior.

__________ pituitary is neural.

posterior.

Hormones released by the pituitary are directly controlled by the __________.

hypothalamus.

The anterior pituitary is controlled by the hypothalamus via a __________ __________.

vascular link (portal system).

Portal system is a specialized region of the circulatory system consisting of 2 capillary beds connected by two __________ __________ that directly transports hormones of the hypothalamus to the anterior pituitary.

portal vessels.

Portal system is a specialized region of the circulatory system with ensures the hypothalamic hormones are transported directly to the __________ pituitary without significant __________, thus requiring less hormone.

anterior; dilution.

Neurosecretory neuron cell bodies located in the hypothalamus synthesize __________ and __________.

vasopressin (ADH) and oxytocin.

Neurosecretory neuron cell bodies in the hypothalamus that synthesize ADH and oxytocin are __________ & __________ nuclei.

supraoptic & paraventricular.

Axons from neurosecretory hypothalamus neurons travel to the __________ pituitary.

posterior.

Hormones are stored in the __________ __________ in posterior pituitary until stimulated for release.

axon terminals.

Cells within each nuclei can make either vasopressin (ADH) or oxytocin, but not __________.

both.

Anterior pituitary synthesizes:

tropic hormones and prolactin.

Tropic hormones synthesized by the anterior pituitary include:

GH, TSH, ACTH, FSH, and LH.

Tropic hormones regulate secretion of another specific __________ __________.

endocrine gland.

2 gonadotropins:

FSH, LH.

Anterior pituitary hormone release can be regulated by two factors:

hypothalamic hormones;

feedback by target-gland hormones.

Hypothalamic hormones can be __________ and/or __________ hormones.

releasing; inhibiting.

__________ __________ is often referred to as the master gland of the body.

anterior pituitary.

The function of the hormones of the anterior pituitary is to control __________, __________, and __________.

growth, metabolism, reproduction.

Hormones regulated by both releasing and inhibiting hormones:

PRL, GH.

PRL plays a role in the __________ __________ for both males and females.

immune response.

Gonadotropins regulates __________ activity in the gonads.

hormone.

TSH regulates hormone secretion of the __________.

thyroid.

ACTH regulates hormone production and secretion of the __________ __________.

adrenal cortex.

GH (somatostatin) affects __________ and regulates hormone production by the __________.

metabolism; liver.

Two feedback loops that suppress hormone secretion in earlier steps of the pathway:

short-loop, long-loop negative feedback.

In short-loop negative feedback, tropic hormone from anterior pituitary feeds back to __________ hypothalamic secretion.

suppress.

In long-loop negative feedback, hormone from an __________ __________ feeds back to the anterior pituitary, hypothalamus, or both to suppress regulatory hormone secretion.

endocrine gland.