PSYCH 4644: FINAL REVIEW Flashcards
Berthold’s Experiment
Transplanted testes developed blood connections and became functional (i.e. produced sperm )
Concluded that the testes produced a blood-born product that affects anatomy and behavior (since nerve connections severed)
1849: A. A. Berthold performed first formal endocrinology experiment
Demonstrated non-neural contribution by the testes required for normal development of a rooster
Prepubertal castration of male chick was used to make capons for more tender meat.
Berthold wanted to know if these extensive effects were dependent on neural connection to the testes.
• Transplanted testes were fully functional
• Birds with transplanted testes were entirely normal
– Normal appearance
• Combs, wattles, plumage
– Normal behavior
• Normal vocalizing
• Normal aggression
• Normal mating

• Hypothesized secretory product carried by blood to target tissues
– Learned later to be testosterone
Techniques in
Behavioral Endocrinology
Assays: measure hormone levels.
Bioassays
RIA, EIA, ELISA
Ablation and replacement
Lesion
Electrical stimulation
Optogenetics
Electrophysiological recording
Pharmacological Techniques: agonists & antagonists
Immunocytochemistry
Immediate early genes
Autoradiography
Western blot
In situ hybridization
Genetic manipulations
Histology
Brain Imaging
Endocrinology Technique #1:
Ablation & Replacement
This method is like that employed by Berthold.
It is the removal (ablation) of a suspected hormone source or by replacement via implantation or by injection of suspected hormonal chemicals
Technique #2:
Bioassays
The use of a biological response to determine the PRESENCE or AMOUNT of a particular substance in a sample.
Identifies the chemical processes in a hormone’s actions.
Involves testing the hormone on a living animal or cell culture.
Bioassays are often usefully conducted on alternate species from which a hormone has been derived.
Bioassay for Prolactin:
In this case, the cell height of the crop sac is going to differentiate dependent upon the amount of prolactin injected.
Technique #3: Immunoassays
The most famous form is the radioimmunoassay (RIA) and it is a technique that was first able to measure hormones PRECISELY.
Rosalyn Yalow received the Nobel Prize in for her work on this technique.
Radioimmunoassays
Type of Immunoassay.
- Antibody to a Hormone and the Labeled Hormone are mixed in solution.
- The Labeled Hormone binds with the Antibody.
- Unlabeled Hormone is added.
- The Unlabeled Hormone and Labeled Hormone compete for binding sites.
- The percentage of bound Labeled Hormone is measured and a standard curve is developed.
- The standard curve is used to determine the amount of Unlabeled Hormone in a given sample.
Technique #4: Immunocytochemistry
A technique that it uses antibodies to determine the LOCATION of hormones or hormones receptors.
Often, these antibodies are attached to a fluorescent dye for viewing under a fluorescent microscope.
Technique #5
Autoradiography
Radiolabeled hormones are injected into a tissue or animal and the sections taken will reveal sites of absorption and radioactivity.
A technique used to detect a radiolabeled substance, such as a hormone, in a cell or organism, by placing a thin slice of the material in contact with a photographic emulsion, which displays darkened silver grains in response to the radioactive emissions.
Technique #6
Blot Tests
A cellular technique that is used to discern if a particular protein or nucleic acid is found in a given tissue.
The various forms of these techniques involve electrophoresis of homogenates of tissues from which proteins are extracted.
Electrophoresis will separate these proteins on the basis of electrical charge.
Technique #7
“in-Situ” Hybridization
A technique that will allow examination of gene expression in cells, tissues, or organs are identified for a specific protein.
Technique #8
Stimulation Followed With Recordings
Direct electrical stimulation of neuronal pools (brain, spinal cord, or peripheral nerves) can elicit electrical activity in cells and tissues of neurall relevant sites.
Rat with electrodes implanted in the brain to allow stimulation of specific regions of the hypothalamus (a major endocrine secreting region).
Technique #9
Pharmacological Techniques
The use of chemical agents that may alter the action or function of a hormone.
The 2 major groups are:
AGONISTS – hormone mimics
ANTAGONISTS – hormone blockers
These compounds can be administered to an animal in a variety of ways, but the two most common forms are:
CANNULATION – a form of permanent form of injection tube is implanted in a target region. Used typically for multiple administrations of a pharmacological agent.
SIMPLE INJECTION – using syringes to administer a single dose of a pharmacological agent
Technique #10
Anastomosis
An older technique whereby the blood systems of two different animals is interconnected to study the endocrine systems of the two animals.
Technique #11
Microdialysis
Much like kidney dialysis, it is a technique that allows the administration of very minute quantities of neurotransmitters, hormones and/or other pharmacological agents into a conscious animal.
But the experimental benefit is that samples (chemical or electrical) from the site are also possible.
Technique #12
Brain Imaging
Scanning techiques of various forms that are used to remotely monitor and test the activity of body structure function, esp. that of the brain.
There are several types of these devices including:
Positron Emission Tomography: (PET): will show functioning of brain regions in real time.
Computer Assisted Tomography (CT) – uses x-rays to give a 3-D image of the brain within a particular plane of space.
Magnetic Resonance Imaging (MRI) - using non-ionizing radiation energy to see images similar to CT scans.
Technique #13
Genetic Manipulations
Engineering knockout mice
Technique #13
Microarrays
This tool is capable of showing the expression (activity) of genes within an animal’s genome.
AKA, “Gene Arrays”
Leptin Example:
Both mice have a defective “ob” gene, resulting in development of obesity.
The normal-weight mouse was given daily injections of the leptin protein, the protein that the “ob” gene encodes, to rescue the effects of its mutation.
Histology!!!
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Optogenetics!!!
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WHAT ARE HORMONES ?
Chemicals produced and released in very small amount by ENDOCRINE glands into the bloodstream
Hormones are not released constantly but instead are released in spurts (pulsatile secretion)
Travel some distance to target organs or tissues
Target cells have specific receptors
Regulates cellular events that lead to activation of enzymatic pathways or to effects on gene expression and protein synthesis
Principal actions of hormones:
Metabolism
Growth
Developmental Processes
Behavior
Hormonal Communication
- Uses hormones
- Released into circulatory system
- Travels long distances (1mm-2m)
- Can travel anywhere in the body
- Slow, graded
- Mediate long-term processes
- Little voluntary control
Think blood
Neural Communication
- Uses neurotransmitters
- Released locally into synapse
- Travels short distances (20-30 nm)
- Can travel only along neural tracts
- Fast, all or none
- Mediates fast changes
- Some voluntary control
Think action potentials..
Endocrine system
Consists of endocrine glands which have cells that release chemical messages (i.e. hormones) into the blood stream
Endocrine effects as contrasted with:
- Autocrine
- Paracrine
Not mutually exclusive:
A hormone can act in an autocrine, paracrine, and endocrine fashion.
Autocrine
Pertaining to a signal secreted by a cell into the environment that affects the transmitting cell.
Autocrine signaling is a form of cell signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in itself.
Paracrine
Paracrine signaling is a form of cell-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior or differentiation of those cells.
Endocrine Glands
Hypothalamus
Pineal Gland
Pituitary Gland
Thyroid Gland
Adrenal Glands
Pancreas (Islets of Langerhans)
Gonads
Hypothalamus
Part of the diencephalon, located just below the thalamus.
Important in the regulation of autonomic & endocrine functions.
The hypothalamus consists of several collections of nerve cell bodies (i.e., nuclei),
Regulates endocrine function by releasing neurohormones into the hypothalamic–pituitary portal system and by releasing hormones into the circulation of the posterior pituitary gland.
In the Hypothalamus’ median eminence, specialized neurons called neurosecretory cells secrete neurohormone (hormones released from a neuron) into the blood vessels of the pituitary
Pineal Gland
An endocrine gland (also called the epiphysis), located in between the telencephalon and diencephalon
Secretes melatonin, a hormone important inthe regulation of daily and seasonal cycles.
Anterior Pituitary
Front part of the endocrine gland.
Extends from the base of the brain.
Secretes a number of TROPIC hormones in response to hormonal signals from the HYPOTHALAMUS.
Receives little, if any neural input
Neurohormones from the hypothalamus reach the anterior pituitary via the PORTAL BLOOD SYSTEM
Causes release of tropic hormones that stimulate various physiological processes either by acting directly on target cells or by causing other endocrine glands to release hormones.
Tropic hormones
Tropic hormones are hormones that have other endocrine glands as their target.
Most tropic hormones are produced and secreted by the anterior pituitary.
Posterior pituitary
The rear part of the endocrine gland that extends from the base of the brain.
Stores & releases OXYTOCIN and VASOPRESSIN (or some variant of these nonapeptide hormones) which are produced in the hypothalamus.
Hormones are secreted directly from neurons into the blood
Thyroid Gland
A double-lobed endocrine gland located on or near the trachea or esophagus in vertebrates.
Secretes several hormones important in metabolism, including triiodothyronine and thyroxine.
Adrenal Glands
Paired, dual-compartment endocrine glands in vertebrates consisting of a medulla and a cortex.
Epinephrine & Norepinephrine are secreted from the medulla.
Steroid hormones are released from the cortex.
Adrenal Medulla
The inner portion of the endocrine organ that sits above the kidneys.
Secretes Epinephrine & Norepinephrine.
Adrenal Cortex
The outer layer(s) of the endocrine organ that sits above the kidney.
Secretes steroid hormones.
Pancreas
A compositevertebrate gland with both endocrine and exocrine functions.
The pancreas is located within the curve of the duodenum behind the stomach & liver
Secretes digestive enzymes (exocrine function).
Secretes insulin, glucagon, and somatostatin (endocrine function).
Also secretes bicarbonate.
Islets of Langerhans
Islands of endocrine tissue nested throughout the exocrine tissue of the pancreas.
There are 4 different cell types among the islets of Langerhans, each of which secretes a different type of protein hormone.
Steroid Hormones
Fat soluble (i.e. can easily move through cell membranes)
NOT soluble in water!!!
Thus, require carrier proteins for transport through the blood to their target tissue
Receptors located inside the cells (cytosol or nucleus)
Have slow but lasting effects
Carrier protein example:
Sex hormone binding globulin (SHBG)
A class of structurally related fat-soluble chemicals that are derived from cholesterol.
Characterized by three 6-carbon rings plus one conjugated 5-carbon ring.
Examples of Steroid Hormones:
Steroid hormones can be grouped into 5 groups by the receptors to which they bind:
Glucocorticoids Mineralocorticoids Androgens Estrogens Progestogens
Vitamin D derivatives are a 6th closely related hormone system with homologous receptors.
Protein & Peptide Hormones
Made up of individual amino acids:
Peptide (small)
Protein/polypeptide (large)
Stored in vesicles of endocrine cells
Released into circulation by exocytosis
Soluble in blood!!!s
Don’t require carrier proteins.
Act rapidly (i.e. seconds to minutes)
Can vary in their sequence of amino acids
Examples of Protein & Peptide Hormones
Neurohormones of the Hypothalamus
Tropic Hormones of the Anterior Pituitary
Posterior pituitary hormones
Parathyroid hormone
Calcitonin
Gastrointestinal hormones
Ghrelin & Leptin
Pancreatic hormones
How are hormones regulated?
The most common form of hormone regulation is NEGATIVE FEEDBACK
NEGATIVE FEEDBACK:
The product of the target tissue feeds back on the source of the hormone to stop hormone production.
POSITIVE FEEDBACK:
The production of hormone stimulates additional hormone production.
Sexual differentiation
the process of becoming a male or female
List the Order of Sexual Differention
- Chromosomal sex
- Gonadal sex
- Hormonal sex
- Morphological sex
- Behavioral sex
Chromosomal sex:
Female: XX, homogametic
Male: XY, heterogametic
Gonadal sex:
Females: ovaries, eggs
Males: testes, sperm
Related to gametic sex.
Hormonal sex:
Female: high estrogen, low androgen
Male: high androgen, low estrogen
Morphological sex:
differences in body type, CNS, and effector organs (i.e., muscles)