Regulation of Reproduction Flashcards
endocrine gland
any gland responsible for the secretion of hormones directly
into the blood stream
hormone
chemical messenger produced by a ductless gland or tissue and
carried in the blood to a target organ where it effects a change in cellular activity
target tissue
tissue upon which a hormone acts
receptors
where hormones bind to (at the tissue or target cells)Specific
binding site for hormone within a target tissue (two types)
two types of receptors
1) plasma membrane receptor
2) nuclear receptor
nervous system job
translation of external stimuli into neural/chemical signals
which affects activities of reproductive organs and tissues
simple neural reflex
efferent neurons send signal via neurotransmitters to target tissue
neuroendocrine reflex
neurohormones secreted by nerve cells into circulation (blood) where
they travel to target tissue
types of hormones
neurohormone proteins peptides glycoproteins steroids fatty acids
neurohormone
hormone secreted by nerve cells directly into
blood OR has an effect on adjacent cell
protein hormone
- Made of long chain of amino acid
- Water soluble
- Not orally active (not affective if administered orally)
- i.e prolactin, relaxin, lacental lactogen, ACTH
- Receptors located on PLASMA MEMBRANE
peptide hormone
- Few to several amino acids in length
- i.e. GnRH, oxytocin
- Receptors located on PLASMA MEMBRANE
glycoprotein hormone
- Proteins with sugar molecules added (glycosylated)
to increase half-life - Composed of an alpha and a beta subunit
- i.e FSH, LH, inhibin, hCG, eCG
- Receptors located on PLASMA MEMBRANE
steroid hormone
- Made from cholesterol
- Water insoluble, attach to proteins in blood
- Are orally active
- All have 4-carbon ring structure
- i.e. Androgens, Estrogens, Progesterone
- Receptors located in NUCLEUS (and PLASMA MEMBRANE = slow
response)
fatty acid hormone
- Prostaglandins (PGF2a, PGE2)
2. Receptors located on PLASMA MEMBRANE
hypothalamic-hypophyseal portal system
the hypothalamus releases hormones that acts upon the pituitary gland via a blood portal system
known as the
gonadotropin-releasing hormone (GnRH)
a. Causes LH/FSH release from ANTERIOR PITUITARY b. 10 amino acids long (synthetic forms available) c. Active in very small amounts d. Uses in reproduction: (1) Treatment of cystic follicles (2) Out-of-season breeding (estrous synchronization) (3) Contraception
hypothalamic hormone
controls the pituitary
anterior pituitary
composed of epithelial tissue
posterior pituitary
composed of neural tissue
anterior pituitary hormones
LH
FSH
Prolactin
ACTH
Luteinizing Hormone (LH)
a. Ovulation
b. Corpus luteum formation & function
c. Testosterone production
* Receptors located on theca cells, luteal cells, Leydig cells
targets- gonads, follicles, Leydig cells
Follicle-Stimulating Hormone (FSH)
a. Follicle growth
b. Estrogen release
c. Spermiogenesis
* Receptors located on granulosa cells, Sertoli cells
targets- gonads, follicles
Prolactin
a. Protein synthesis by mammary gland, control CL function in some
Milk synthesis
*Receptors on mammary cells, luteal cells (in rats/cats), gonads
Adrenocorticotropic Hormone (ACTH)
a. Glucocorticoid release from the adrenal gland at parturition or stress
situation
posterior pituitary hormones
- Site of hormone release, NOT synthesis
- Has neural connections to hypothalamus
oxytocin
ADH
oxytocin
a. Milk letdown
b. Uterine contractions, parturition & sperm transport
c. Prostaglandin synthesis
targets- endo/myometrium, mammary glands
Anti-Diuretic Hormone (ADH)
a. regulate blood pressure
steroid hormones
estrogens
progestins
androgens
glucocorticoids
estrogens are located
granulosa cells and placenta
estrogens
estradiol (E2)
- Estrus/heat: sexual behavior
- Mammary alveolar growth & development
- Secondary sex characteristics
- Uterine motility
- Control of GnRH secretion
targets- hypothalamus, reproductive tract, mammary gland
progestins are located
corpus luteum and placenta
progestins
progesterone (P4)
- Inhibit estrus
- Maintain pregnancy/ increase uterine gland secretions (hystotrophe)
- Mammary alveolar and ductal growth
- Control GnRH and LH secretion
targets- hypothalamus, reproductive tract, mammary gland
androgens are located
leydig cells and theca cells
androgens
testosterone (T)
- Male behavior
- Spermatogenesis
- Promotes accessory sex gland secretions
- Controls GnrH and LH secretion
targets- hypothalamus, seminiferous tubules, accessory sex glands
glucocorticoids are located
adrenal cortex
glucocorticoids
cortisol
- Parturition
- Milk synthesis
prostaglandins in males
- Parturition
2. Milk synthesis
prostaglandins in females
- Secreted by endometrium
- Control estrus
- Induce luteolysis (determines life of corpus luteum)
- Plays role in maternal recognition
inhibin
a. Inhibits FSH release
b. SOURCE: Dominant follicles, Sertoli cells
relaxin
a. SOURCE: Corpus luteum, placenta
b. Important in parturition
i. Pelvic expansion
ii. Cervical dilation
plasma membrane receptors mode of action
2nd messenger system
plasma membrane receptors pathway
Peptides/proteins —>bind cell membrane receptor → activate adenyl cyclase →
[ATP → cAMP] → cAMP → ↑protein kinase A (enzyme) → protein phosphorylation
→ protein synthesis
nuclear receptors include
cytosolic receptors, intracellular receptors
The receptors are inside of the cell either in the cytoplasm or in the nucleus
nuclear receptors mode of action
involves nucleus directly
nuclear receptors pathway
steroids → bind to cytoplasmic receptors → translocate to nucleus → bind to
chromatin (DNA) → initiate gene transcription → RNA synthesis → protein
synthesis
hormone characteristics
1) short half lives
2) released in small amounts
3) must bind to specific receptors to cause an action (lock and key mechanism)
hypothalamus secretion
usually peptides that regulate release of hormones from the pituitary
what is GnRH
peptide
what are the “kissing sisters”
LH and FSH
what are the functions of anterior pituitary hormones
proteins and glycoproteins that regulate functions in testis and ovaries
ovary and testis function
secretion of steroids to regulate
- GnRH and gonadotropin
- uterine and accessory gland function
- sex characteristics and bone metabolism
if you increase granulosa cells, what will happen?
an increase in estradiol
why do you have to produce testosterone for mammary gland development?
you have to go through testosterone before you get to estradiol
prostaglandin F2-alpha
targets- hypothalamus, seminiferous tubules, accessory sex glands
hormone receptors
hormone travels through blood and thus all body cells are exposed to it
hormones in nuclear receptors
GnRH LH FSH Prolactin ACTH
hormones in plasma membrane receptors
Oxytocin
ADH
Prostaglandin
