Reproductive Hormones

Question 1

What ensures life sustaining activities?

Answer 1

Hormones

Question 2

Define autocrine mode of action

Answer 2

The hormone acts on the same cell that produced it.

Question 3

Define endocrine mode of action

Answer 3

The hormone is distributed in blood and binds to distant target cells.

Question 4

Define paracrine mode of action

Answer 4

The hormone acts locally by diffusing from its source to adjacent
target cells.

Question 5

How are most reproductive hormones secreted?

Answer 5

In a pulsatile fashion.

Question 6

How are hormones secreted in females compared to males?

Answer 6

Periodically in females (in regular cycles) and constitutively in males.

Question 7

What is notable about the effectiveness of hormones?

Answer 7

They are effective even in very minute quantities (i.e., picograms per milliliter).

Question 8

Is the half life of reproductive hormones long or short

Answer 8

Relatively short

Question 9

What do hormones regulate in reproductive and some non-reproductive tissues?

Answer 9

Intracellular biochemical reactions.

Question 10

What can reproductive hormones control/stimulate/maintain? (5)

Answer 10

• Control other hormone release (releasing hormones/ factors)
• Stimulate gonads (gonadotropic hormones)
• Stimulate sexual development and sustain gonadal function, alter secondary sex characteristics
• Maintain pregnancy, initiate and sustain parturition and lactation
• Control ovarian cyclicity (e.g., ovulatory process, CL formation and regression)

Question 11

What are three ways to classify repro hormones?

Answer 11

-Source
-Mode of action
-Biochemical classification

Question 12

What are the three sources of repro hormones?

Answer 12

Hypothalamic, pituitary, gonadal

Question 13

What are the four modes of action for repro hormones?

Answer 13

• Neurohormones
• Releasing
  hormones/factors
• Gonadotropins
• Metabolic/sexual
  stimulants

Question 14

What are the 3 types of biochemical classification?

Answer 14

-Peptides, steroids, FA derivatives

Question 15

Steps for the fate of steroid hormones after secretion (7 steps)

Answer 15

1. Steroid secreted by gonad
2. Steroid enters blood and goes to target tissue
3. Steroid causes change in target tissue
4. Steroid in blood passes through liver
5. Liver renders sterid H2O soluble
6. Re-enters blood and enters kidney or enters bile
7. Excreted in urine and/or feces as glucuronide or sulfate

Question 16

What is an example of POSITIVE feedback for repro hormones?

Answer 16

increased estradiol
-> increased GnRH from hypothalamus
-> increased LH from pituitary
-> increase stimulates terminal follicular development, ovulation and early CL

Question 17

What is the surge center in the hypothalamus sensitive to?

Answer 17

Positive feedback

Question 18

What is an example of NEGATIVE feedback for repro hormones?

Answer 18

increased progesterone and estradiol
-> decreased GnRH from hypothalamus
-> decreased LH from pituitary
-> decrease blocks ovulation

Question 19

What is sensitive to negative feedback in the hypothalamus?

Answer 19

Tonic center

Question 20

what is the process of formation of the steroid hormones?

Answer 20

cholesterol -> progesterone -> testosterone -> estradiol

Question 21

Mechanisms of protein hormones (4 steps)

Answer 21

1. Binding of hormone to receptor
2. Activation of adenylate cyclase
3. Activation of protein kinase
4. Synthesis of new products

Question 22

Mechanisms of steroid hormones (4 steps)

Answer 22

1. Transport of steroid
2. Transfer through cell membrane and cytoplasm
3. Binding of steroid to the nuclear receptor
4. Synthesis of mRNA and protein

Question 23

What type of receptors do protein hormones act through?

Answer 23

Plasma membrane receptors

Question 24

What type of receptors do steroid hormones act through?

Answer 24

Nuclear receptors