Chapter 31 — Quiz
Twenty-two items. Mixed format: multiple choice, true/false with justification, and short answer. The
answer key follows in a collapsed block — work the whole set before opening it.
1. In the United States, animal drugs are approved by:
- a) the Department of Agriculture
- b) the FDA's Center for Veterinary Medicine
- c) the American Veterinary Medical Association
- d) individual state veterinary boards
2. Which of the following is not a peptide or peptide-adjacent drug in genuine veterinary use?
- a) GnRH agonists for reproductive management
- b) Insulin for diabetic dogs and cats
- c) Desmopressin for central diabetes insipidus in dogs
- d) BPC-157 for tendon injury in dogs
3. True or false, with one sentence of justification: A substance appearing on a racing
authority's prohibited list is evidence that the substance produces a performance benefit.
4. Name three reasons, other than demonstrated efficacy, that a racing or sporting authority might
prohibit a substance.
5. The compound marketed as TB-500 is best described as:
- a) recombinant human thymosin β4
- b) a short synthetic fragment corresponding to the actin-binding region of thymosin β4
- c) a 43-residue endogenous peptide identical to the human molecule
- d) a growth hormone secretagogue
6. Which pair of endpoints is characteristic of livestock growth-promotion research?
- a) pain scores and quality-of-life indices
- b) tendon histology and return-to-work time
- c) average daily gain and feed conversion ratio
- d) VO2 max and one-repetition maximum
7. The safety endpoints in livestock growth research primarily protect:
- a) the treated animal
- b) the farm worker administering the compound
- c) a human consumer exposed to trace residues in food
- d) the veterinarian who wrote the order
8. Define endpoint mismatch in one sentence.
9. True or false, with justification: A literature can be large, rigorous, and provide no evidence
at all about a given question.
10. The chapter distinguishes "used in animals" from "used in laboratory animals." State the
distinction in one sentence and say why it matters.
11. Rodent thyroid C-cells differ from human C-cells in a way that is central to interpreting the
GLP-1 tumor finding. That difference is:
- a) rodents lack C-cells entirely
- b) rodent C-cells express GLP-1 receptors far more abundantly than human C-cells
- c) human C-cells clear GLP-1 agonists faster
- d) rodent C-cells are located in a different organ
12. Standard cross-species dose conversion normalizes to:
- a) body mass
- b) lean body mass
- c) body surface area
- d) blood volume
13. Naive milligram-per-kilogram conversion from a mouse study to a human:
- a) underestimates the human-equivalent dose, roughly twofold
- b) overestimates the human-equivalent dose, roughly twelvefold
- c) is accurate for peptides but not for small molecules
- d) has no predictable direction of error
14. Beyond the arithmetic, the chapter identifies a second and more serious error in using
surface-area conversion to pick a dose. State it in one sentence.
15. Match each term to its definition: face validity, construct validity, predictive validity.
- i) the model arises from the same underlying mechanism as the human condition
- ii) interventions effective in the model prove effective in humans
- iii) the model superficially resembles the human condition
16. The ob/ob mouse is a model of:
- a) common polygenic obesity
- b) leptin deficiency
- c) leptin resistance
- d) type 2 diabetes with normal adiposity
17. State the four questions to ask of a "it has been used for years" claim.
18. Complete the chapter's formulation: "A track record is not a dataset unless _____."
19. Extra-label use in U.S. veterinary medicine requires all of the following EXCEPT:
- a) a licensed veterinarian within a valid veterinarian-client-patient relationship
- b) that no approved animal drug labeled for the use is clinically adequate
- c) prior written approval from the Center for Veterinary Medicine for each case
- d) an established withdrawal period, for food-producing animals
20. In two sentences, define a withdrawal period and say who it protects.
21. True or false, with justification: This chapter argues that veterinary evidence is weaker than
human evidence.
22. Give one example of a therapeutic peptide or peptide-derived drug whose origin lies in a
non-human species, and name the species.
Answer key
**1.** **b)** the FDA's Center for Veterinary Medicine. (The USDA regulates veterinary biologics such
as vaccines — a common distractor.)
**2.** **d)** BPC-157. It has no labeled indication in any species and is not an approved veterinary
drug. This is the §31.4 point: its animal record is laboratory research, not veterinary practice.
**3.** **False.** A prohibited-substance list is a risk-management document. Substances appear on it
because of uncertainty, welfare concerns, unapproved regulatory status, competitive integrity, or
class-based administrability — none of which is an efficacy finding.
**4.** Any three of: uncertainty about effects; animal welfare, including masking of injury; the
compound's status as an unapproved medicine; integrity of competition and public confidence;
administrability, since prohibiting a whole pharmacological class is easier than adjudicating each
member.
**5.** **b)** a short synthetic fragment corresponding to the actin-binding region. Chapter 18
establishes that the fragment and the 43-residue parent are not the same molecule.
**6.** **c)** average daily gain and feed conversion ratio.
**7.** **c)** a human consumer exposed to trace residues in food. This is close to the opposite of the
exposure a person has when injecting a compound at a bioactive dose, which is why livestock safety
data cannot be read as human safety data.
**8.** A body of evidence is real and rigorous but measured something other than the outcome under
discussion, and is therefore silent on it rather than supportive of it.
**9.** **True.** Rigor governs how well a study answers *its* question. If the question is feed
efficiency and yours is tendon healing, the study's quality is irrelevant to you. Silence is not
weak support; it is no support.
**10.** "Used in animals" implies veterinary practice — a licensed clinician, a labeled product, a
patient. "Used in laboratory animals" means administered as an independent variable in an experiment.
The reassurance people hear is the first; for most Part III compounds the fact is the second.
**11.** **b)** rodent C-cells express GLP-1 receptors far more abundantly. This is a mechanistic reason
to doubt transfer — not proof of human safety, which is why the warning and the surveillance remain.
**12.** **c)** body surface area, which tracks metabolic rate better than mass does.
**13.** **b)** overestimates, roughly twelvefold for mouse-to-human. The error has a fixed direction
because small animals clear faster relative to their size.
**14.** The method is a tool for estimating a maximum safe *starting* dose in a first-in-human safety
study — a deliberately conservative floor — and using it to target an effective dose repurposes a
safety instrument as an efficacy calculator, which it was never designed to be.
**15.** face validity = **iii**; construct validity = **i**; predictive validity = **ii**. Only
predictive validity licenses an animal-to-human inference, and it is the least often established.
**16.** **b)** leptin deficiency. The mouse cannot make leptin. Common human obesity is generally not a
leptin-deficiency state, which is why leptin replacement did not transfer to it (Chapter 13).
**17.** In whom? For what? Measured how? And collected how? (A fifth follows from the fourth: compared
to what?)
**18.** "...somebody was recording."
**19.** **c)** prior written approval for each case. Extra-label use is permitted under statutory
conditions, not case-by-case pre-authorization. The other three are genuine requirements.
**20.** A withdrawal period is the interval that must elapse after treating a food-producing animal
before its meat, milk, or eggs may enter the human food supply. It protects a human consumer who never
met the animal, from trace residue exposure — an entire regulatory arm with no analogue in human
medicine.
**21.** **False.** The chapter rates GnRH agonists in veterinary species ✅, on the same machinery it
uses to rate ❌ elsewhere. The argument is about scope: evidence answers the question it was pointed
at, in the population it was gathered in. Applying veterinary evidence to a human claim is the error,
not gathering it.
**22.** Acceptable answers include: exenatide, from exendin-4 in Gila monster venom; the ancestor of
the first orally active ACE inhibitor, from pit viper venom; the cone snail-derived analgesic; salmon
calcitonin, from fish. Insulin from bovine or porcine pancreas is also acceptable.