History of Endocrinology

Question 1

Who conducted the first recorded endocrine experiment and when?

Answer 1

Professor Arnold A. Berthold in 1849

Berthold’s experiment involved castration and transplantation of testes in roosters.

Question 2

What were the observed effects of prepubertal castration in male chicks?

Answer 2

Reduced secondary male appearance and failure to exhibit male behavior

This observation led to further investigations into the role of the testes.

Question 3

What did Berthold conclude about the function of the testes?

Answer 3

Testes secreted something that conditioned the blood to cause development of male characteristics

Berthold speculated on the mechanisms of hormone action.

Question 4

What year was the first critical experiment demonstrating the existence of a hormone reported?

Answer 4

1902

This experiment involved the stimulation of pancreatic secretion by acid in isolated sections of the jejunum.

Question 5

What did the 1902 experiment demonstrate about pancreatic enzymes?

Answer 5

Control of pancreatic enzymes was mediated by bloodborne stimulation

This was shown by introducing acid into an isolated but vascularised section of the jejunum.

Question 6

What are the physiological levels of hormone concentrations used in endocrinology studies?

Answer 6

Ranges of ug/ml – pg/ml in blood or extracellular fluid

These ranges are significantly lower than pharmacological levels.

Question 7

What are pharmacological levels of hormones commonly in?

Answer 7

mg/ml range

Pharmacological doses may produce effects different from physiological levels.

Question 8

What are the advantages of using whole animal models in endocrinology?

Answer 8

Monitor physiological responses and study complex interactions

Whole animal studies allow for comprehensive analysis of endocrine function.

Question 9

What is one method for observing effects after removing an endocrine organ?

Answer 9

Atrophy of target organs

Observing changes in hormone concentrations can also provide insights.

Question 10

What types of drugs can manipulate the endocrine system?

Answer 10

Agonists, antagonists, and inhibitors

These drugs can mimic, block, or inhibit hormone actions.

Question 11

Fill in the blank: The _______ is the organ responsible for secreting hormones in the endocrine system.

Answer 11

[testes]

This refers to Berthold’s studies on the testes and their role in male characteristics.

Question 12

What are the considerations when selecting an experimental test system?

Answer 12

Appropriate cell type, duration of treatment, and cell viability

These factors are crucial for the reliability of experimental outcomes.

Question 13

True or False: Hormone receptor antagonists block the action of hormones at the receptor.

Answer 13

True

Antagonists inhibit the effects of hormones by binding to their receptors.

Question 14

What is one example of a pharmacological manipulation in endocrinology?

Answer 14

Cyproterone acetate as a testosterone receptor antagonist

This drug is used to study hormonal effects in various conditions.

Question 15

What is the role of feedback control in hormone synthesis?

Answer 15

Regulates the synthesis of hormones based on physiological needs

Feedback mechanisms ensure homeostasis in hormone levels.

Question 16

What is a limitation of in vitro experimental models?

Answer 16

Lack of complex physiological interactions

In vitro models may not fully represent in vivo conditions.

Question 17

What is meant by comparative endocrinology?

Answer 17

Study of endocrine systems across different species

This approach helps understand evolutionary adaptations in hormone function.