Hormones

Question 1

Hypothalamus

Answer 1

• short chain polypeptides

- cause the release of trophic hormones from anterior pituitary

Question 2

Gonadotropin releasing hormone (GnRH)

Answer 2

-causes release of FSH and LH from anterior pituitary

Question 3

Thyrotrophin releasing hormone (TRH)

Answer 3

Release TSH and prolactin from anterior pituitary

Question 4

Corticotrophin releasing hormone

Answer 4

Release ACTH from anterior pituitary

Question 5

growth hormone releasing hormone(GHRH)

Answer 5

Release growth hormone from anterior pituitary

Question 6

Somatostatin

Answer 6

• growth hormone inhibiting hormone

- inhibits growth hormone release from anterior pituitary

Question 7

How hormones get from hypothalamus to anterior pituitary

Answer 7

-capillary plexus is fused with hypophyseal portal vessels

Question 8

Posterior pituitary hormones

Answer 8

• polypeptides

- oxytocin

Question 9

Oxytocin

Answer 9

• smooth muscle contraction in mammary glands, uterus, oviduct
• Made in hypothalamus and secreted in posterior pituitary
• can be produced in corpus luteum of some species

Question 10

Anterior pituitary hormones

Answer 10

• glycoproteins or proteins
• FSH
• LH
• ACTH
• TSH
• prolactin
• GH

Question 11

FSH

Answer 11

Stimulates follicle growth and spermatogenesis

Question 12

LH

Answer 12

• causes ovulation and maturation of Oocyte
• maintains CL
• stimulates androgen secretion by leydig cells

Question 13

Prolactin

Answer 13

• stimulates maternal behavior

- rodents: maintains CL

Question 14

ACTH (Corticotrophin)

Answer 14

Stimulates cortisol release from adrenal gland

Question 15

TSH

Answer 15

Stimulates thyroxine release from thyroid gland

Question 16

Structure of LH, FSH and TSH

Answer 16

-have 2 aa chains but beta chains differ and give specificity

Question 17

Placental hormones

Answer 17

• eCG
• hCG
• PL

Question 18

ECG - equine chorionic gonadotropin

Answer 18

• contains mainly FSH activity but also a little LH activity
• longer half life than FSH
• helps maintain CL
• found in blood but not urine
• stimulates follicular devel in mare during pregnancy
• LH activity stimulates developing follicles to ovulate and form accessory CLs

Question 19

Commercial hormones from equine placenta

Answer 19

Estrogens

• found in mare urine
• Premarin -commercial product
• estrogen replacement therapy
• prevention of osteoporosis
• prevention of heart disease

Question 20

HCG

Human hot ionic gonadotropin

Answer 20

• LH like activity
• found in blood and urine
• prevents CL regression

Question 21

PL (placental lactogen)

Answer 21

• has GH and prolactin like activity

- prepare the mammary gland for lactation

Question 22

Gonadal hormones-peptides

Answer 22

• relaxin

- inhibin

Question 23

Relaxin

Answer 23

• made of 2 polypeptides
• secreted by CL during pregnancy
• can be secreted by uterus and placenta in some species
• tissue must be exposed to estrogen for effect
• cervical dilation; inhibits uterine contractions

Question 24

Inhibin

Answer 24

• sec by sertoli cells

- inhibit FSH secretion without LH secretion

Question 25

Gonadal steroids

Answer 25

- secreted from ovary, testis, adrenal - androgens - estrogens - progestins

Question 26

Steroid synthesis

Answer 26

- cholesterol-->pregnenolone-->progesterone-->testosterone-->estradiol - cholesterol-->pregnenolone (mito), rest in smooth ER - side chain cleavage is the rate limiting step ;dec number of carbons in conversions

Question 27

Androgens

Answer 27

- ie testosterone - produced by leydig cells, theca interna and adrenal gland - transported by binding to steroid binding globulin - active form: dihydrotestosterone

Question 28

Androgen function in male

Answer 28

- stimulates spermatogenesis - maintain epididymis function - promotes growth, activity and development of accessory sex glands and secondary sex organs - inhibits GnRH release - anabolic activity

Question 29

Estrogens

Answer 29

- ie estradiol - produced in granulosa cells of follicle, sertoli cells in the testes, placenta and adrenal gland - inc mass and contractility of uterus - devel of female secondary sex characteristics - stim or inhibits GnRH release

Question 30

Progestin

Answer 30

- ie progesterone - produced in CL, placenta and adrenal gland - transported in blood to steroid binding globulin - prepares uterus for implantation and pregnancy - acts with estrogen to induce the behavior patterns of estrus - develop alveoli in mammary gland - inhibit rise of LH that causes ovulation

Question 31

Prostaglandins

Answer 31

- fatty acid hormone - regulate smooth muscle contractions and relaxation - produced in many tissues-usually acts locally - ie PGF, PGE

Question 32

PGF

Answer 32

- vasoconstriction - CL regression - ovulation - parturition - sperm transport

Question 33

PGE

Answer 33

- vasodilation - maintain CL - Ovulation - implantation

Question 34

Melatonin

Answer 34

- secreted from pineal gland, just below skull - modified amino acid - integrates effect of light on reproductive processes - involved in seasonality

Question 35

Human menopausal gonadotropin (HMG)

Answer 35

``` -secreted from anterior pituitary During and after menopause -run out of follicles -FSH-like activity -modified FSH molecule -collected in urine and sold to stimulate follicular development in women ```