Basics of Reproductive Endocrinology

Question 1

What two systems regulate the reproductive system?

Answer 1

Simple neural reflex

Neuroendocrine reflex

Question 2

How does the simple neural reflex work?

Answer 2

Employs nerves that release simple neurotransmitters directly onto target tissue
I.e: the body is hot the testicles will drop further from the body to help keep the testicles cool

Question 3

How does the neuroendocrine reflex work?

Answer 3

Neurohomone is released by a neuron, enters blood and acts on remote target tissue
I.e: calf wants milk thumps the mammary glands and that stimulus travels to the brain, stimulating the hypothalamus to release oxytocin from the posterior pituitary which will in turn stimulate milk let down

Question 4

What is the difference in males vs. females in the make up of the hypothalamus?

Answer 4

Males: Tonic center
Females: Tonic and surge center

Question 5

What are 8 functions of reproductive hormones?

Answer 5

Act in small quantities
Short half-lives
Bind specific receptors
Release of other hormones 
Stimulate the gonads
Cause sexual promotion
Maintain pregnancy
Luteolysis

Question 6

What hormones are considered a peptide?

Answer 6

GnRH=decapeptide

Question 7

What hormones are considered to be a glycoprotein?

Answer 7

FSH, LH and inhibin

Question 8

What hormones are considered to be a steroid?

Answer 8

Progesterone
Testosterone
Estradiol

Question 9

What hormones are considered to be a prostaglandin?

Answer 9

Lipid based PGF2a and PGE2

Question 10

What are the functions of PGF2a and PGE2?

Answer 10

PGF2a: cause of luetolysis, flush the uterus (contraction agent)
PGE2: relax the cervix (relaxation agent)

Question 11

What is the difference in how steroid vs. protein hormones travel?

Answer 11

Steroid hormones: travel freely through plasma membrane into cytoplasm and bind directly on specific nucleus
Protein hormones: bind to plasma membrane bound receptors

Question 12

What influences the onset of puberty in small ruminants and pigs?

Answer 12

Pheromones

Question 13

How are steroid hormones metabolized and excreted?

Answer 13

Metabolized in liver

Excreted in urine and feces

Question 14

How are protein hormones metabolized and excreted?

Answer 14

Liver and kidney

Question 15

Where is GnRH from, what is the target tissue (male vs. female) and the primary action?

Answer 15

Source: hypothalamic surge and tonic centers
Male target tissue: Anterior lobe pituitary
Female target tissue: Anterior lobe pituitary
Male primary action: release of FSH/LH from anterior lobe
Female: release FSH/LH from anterior lobe

Question 16

Where is LH from, what is the target tissue (male vs. female) and the primary action?

Answer 16

Source: anterior lobe
Male target: Testis (leydig cells)
Female target: ovary (theca interna and luteal cells)
Male action: stimulates testosterone production
Female action: stimulates ovulation formation of CL and progesterone secretion

Question 17

Where is FSH from, what is the target tissue (male vs. female) and the primary action?

Answer 17

Source: Anterior lobe
Male target: Testis (sertoli cells)
Female target: Ovary (granulosa cells)
Male action: Sertoli cell function
Female action: follicular development and estradiol synthesis