Adenohypophysis (Anterior Pituitary) Gland

Question 1

List the primary trophic hormones and their major actions

Answer 1

Gonadotropins (FSH, LH): move from the hypothalamus to the AP, have stimulatory effects on the testes and ovaries
TSH (Thyroid Stimulating Hormone)- stimulate T4 and T3 production in the Thyroid gland
PRL (Prolactin): continuously secreted unless inhibited by dopamine, functions in the mammary gland development and milk production in mammals, role in males is unclear
GH (Somatotropin/Growth Hormone): acts on protein, lipid and glucose metabolism, critical in early development
ACTH (Adrenocorticotropic Hormone): stimulates corticosteroid production in the adrenal glands
MSH (Melanocyte Stimulating Hormone): stimulates melanocyte production

Question 2

Discuss species variation in pituitary hormones and the relevance of this information clinically

Answer 2

Varies between species, not all hormones can be used for all animals

Question 3

Describe whether blood levels of pituitary hormones are constant or variable

Answer 3

variable, most are not secreted unless stimulated, can have a pulsatile wave of hormone in the blood; levels will vary depending on when blood is taken relative to each “wave”

Question 4

Name the hypothalamic hormone(s) that regulate each of the major pituitary hormones

Answer 4

GnRH Stimulates LH +FSH
Dopamine Inhibits PRL
Thyrotropin releasing hormone stimulates TSH
GRH stimulates GH
GHIH inhibits GH
CRH stimulates ACTH
Prolactin releasing factor stimulates PRL

Question 5

Describe the major effects of prolactin in mammals

Answer 5

mammary gland development and milk production

Question 6

Describe the main function of LH and FSH in the male

Answer 6

LH -> Leydig cells -> Testosterone, FSH-> Sertoli Cells -> Sperm

Question 7

Define: Hyperprolactinemia

Answer 7

too much prolactin, may or may not be associated with tumor of adenohypophysis, treated with dopamine agonist or surgery

Question 8

Define and give examples of glycoprotein hormones

Answer 8

ex.- FSH, TSH, LH; hormone composed of protein + Carbohydrate, composed of alpha and beta subunit, linked by non covalent bonds

Question 9

Define: Beta subunit

Answer 9

unique to each glycoprotein hormone, confers specificity

Question 10

Define: Alpha subunit

Answer 10

common to all three glycoprotein hormones (TSH, FSH, LH)

Question 11

Define: Inhibin

Answer 11

inhibits FSH secretion

Question 12

Define: Sertoli cells

Answer 12

found in the male reproductive tract, produce sperm in the presence of FSH

Question 13

Define: Leydig cells

Answer 13

found in the male reproductive tract, produce testoterone in the presence of LH

Question 14

Define: Pulsatility

Answer 14

the pulsing of hormone release such as what can be seen with gonadotropins