Endocrinology Lab Techniques

Question 1

What is the general purpose of immunohistochemistry techniques?

Answer 1

Visualization of specific cell components

Question 2

What is the general principle behind the immunohistochemistry method?

Answer 2

Localization of antibody-antigen binding specificity; antibody-antigen interactions are visualized by markers like fluorescent dye, enzymes, radioactive elements, etc.

Question 3

What is surgical ablation?

Answer 3

The removal of a gland or other organ

Question 4

What is the removal of the pituitary gland called?

Answer 4

Hypophysectomy

Question 5

What is the removal of the ovaries called?

Answer 5

Ovariectomy or oophorectomy (spaying)

Question 6

What is the removal of the testes called?

Answer 6

Orchiectomy (castration)

Question 7

What is the removal of the adrenal glands called?

Answer 7

Adrenalectomy

Question 8

What is chemical ablation?

Answer 8

The suppression of endocrine function via chemical means

Question 9

What is one type of chemical ablation discussed in class?

Answer 9

Alloxan suppresses beta cell function and inhibits the release of insulin

Question 10

What is deafferentation?

Answer 10

The removal of the nervous stimulation of the tissue

Question 11

What is a vagotomy?

Answer 11

Disruption of the vagus nerve of gastrin-producing cells of the stomach

Question 12

What is an in vivo bioassay?

Answer 12

A method that measures the biological response caused by a hormone in a live animal, organ, or tissue

Question 13

What was an A-Z pregnancy test?

Answer 13

It was an early type of pregnancy test

Question 14

How did the A-Z pregnancy test work?

Answer 14

The urine of a woman was injected into an immature rat or mouse; if the woman was pregnant, the precence of hCG would cause an estrous reaction in the rat or mouse - the rat or mouse would go into heat despite being developmentally incapable of such

Question 15

What are three disadvantages of in vivo bioassays?

Answer 15

1. A lack of sensitivity - a lot of hormone is usually needed for a response
2. Poor reproducibility - wide variability of response in different animals
3. High cost and difficulty of use - animals and animal preparations

Question 16

What are in vitro bioassays?

Answer 16

A technique that employs a cell culture of recommended biological systems to study the effects of a compound under standard conditions

Question 17

Who developed the radioimmunoassay method?

Answer 17

Rosalyn Yalow

Question 18

What is radioimmunoassay?

Answer 18

A type of in vitro technique used to measure concentrations of antigens without the need to use a bioassay (the concentration of an unknown labeled antigen is obtained by comparing its inhibitory effect on the binding of radioactively labeled antigen to specific antibody)

Question 19

What is the principle behind radioimmunoassays?

Answer 19

Competitive binding between a radiolabelled antigen and an unlabelled antigen to a high affinity antibody

Question 20

What are immunometric assays?

Answer 20

Techniques that use labeled antibodies (not labeled antigens)

Question 21

What is the principle behind immunometric assays?

Answer 21

Noncompetitive binding

Question 22

In an immunometric assay the ______________ generated is _____________ to the amount of hormone present.

Answer 22

Color (or other visualization technique)

Directly proportional

Question 23

What method separates compounds?

Answer 23

Chromatography

Question 24

What do endocrinologists want to know about a hormone?

Answer 24

Source, structure, biosynthesis, secretion, mechanism of secretion, circulation and metabolism, biological actions and roles, mechanism of action, pathphysiological aspects, and comparitive

Question 25

Who conducted experiments on male chicks that were castrated, stating, “The testes act upon the blood, and the blood acts upon the whole organism.”

Answer 25

Arnold Berthold

Question 26

What does CRISPR stand for?

Answer 26

Clusted Regularly Interspaced Short Palindromic Repeats

Question 27

What is CRISPR?

Answer 27

A genetic engineering tool that uses a CRISPR sequence of DNA and its associated protein (Cas9) to edit the base pairs of a gene

Question 28

What is the purpose of a Western blot?

Answer 28

To separate and identify specific proteins from a complex mixture extracted from cells

Question 29

What is the principle behind Western blotting?

Answer 29

It is based on immunochromatography where proteins are separated into polyacrylamide gel according to their molecular weights

Question 30

What are the three main steps in a Western blot?

Answer 30

Gel electrophoresis

Transfer and incubation

Protein marking via antibodies

Question 31

What are reporter gene assays used to study?

Answer 31

Gene expression, gene regulation, and/or the structure of regulatory elements that is visualized via a reporter gene protein

Question 32

What is a luciferase assay?

Answer 32

A reporter gene assay that uses luciferase enzymes as markers of gene expression

Question 33

What is PCR?

Answer 33

Polymerase chain reaction is a technique that amplifies and frames specific DNA sequences

Question 34

What is RT-PCR?

Answer 34

RT-PCR creates a complementary DNA fragment from RNA using reverse transcriptase

Question 35

Why use RT-PCR?

Answer 35

Because RNA is very unstable and difficult to work with

Question 36

What is Northern blotting used for?

Answer 36

To determine if specific RNA sequences are present within a sample

Question 37

What is in situ hybridization?

Answer 37

It is a method used to detect the localization of a particular gene

Question 38

What does RT-PCR provide endocrinologists?

Answer 38

The quantitative measurement of a transcribed gene product from cells and/or tissue