History of Endocrinology Flashcards
What should students be able to explain by the end of the lecture?
Some of the initial experiments that shaped the field of endocrinology.
What is the difference between physiological and pharmacological levels of hormones?
Physiological levels are natural ranges in the body, while pharmacological levels are higher, often used therapeutically.
What are the advantages of in vitro model systems?
Controlled environment, reduced complexity, and focused study on specific cellular responses.
What are the disadvantages of in vivo model systems?
Increased complexity, potential ethical issues, and difficulty in isolating variables.
Who conducted the first recorded endocrine experiment?
Professor Arnold A. Berthold.
What was the focus of Berthold’s experiments?
The effects of prepubertal castration on male roosters.
What were the observed effects of castration in Berthold’s experiments?
- Reduced secondary male characteristics (combs and wattles)
- Failure to exhibit male behavior.
What did Berthold conclude about the testes?
Testes secreted something that conditioned the blood to cause development of male characteristics.
What significant experiment related to hormones was reported in 1902?
The demonstration of the existence of a hormone through the control of pancreatic secretions.
What are the physiological levels of hormones typically measured in?
Ranges of ug/ml to pg/ml in blood or extracellular fluid.
What are pharmacological levels of hormones commonly in?
The mg/ml range, producing circulating levels in excess of natural levels.
What is the effect of pharmacologic doses of hormones compared to physiological levels?
They may produce different responses and have therapeutic uses, but also more risk of toxic response.
What are some examples of experimental test systems in endocrinology?
- Whole animal
- Isolated perfused organs
- Tissue slices
- Isolated cells in culture
- Subcellular fractions.
What are the classical methods used to study endocrine tissues?
Whole animal studies involving removal and replacement of organs.
What effects could be observed after removal of an endocrine organ?
- Atrophy of target organs
- Changes in blood/urine concentration of hormones.
What is the purpose of using agonists in pharmacological manipulation of the endocrine system?
To bind to hormone receptors and mimic the action of the hormone.
What do antagonists do in terms of hormone action?
Block or inhibit the action of hormones at their receptors.
What is a consideration when selecting the appropriate cell type for experimental test systems?
The specific biological relevance to the hormone being studied.
Fill in the blank: The hormone concentrations used in endocrinology studies vary from physiological levels in the range of ______ to ______.
[ug/ml] to [pg/ml].
True or False: The control animals in endocrine studies are treated the same as experimental animals.
False.
What is a potential limitation of experimental models in endocrinology?
Variability in hormone responses and the relevance of the model to human physiology.
What is the role of feedback control in hormone biosynthesis?
It regulates the synthesis of hormones based on physiological needs.
What should be measured as endpoints in hormone exposure experiments?
Biological responses, hormone levels, and physiological changes.
