hormones and mammary growth
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Hormones and Mammary Growth
TGF-b Effect on Mammary Growth in Culture
Epidermal Growth Factor and Mammary Growth
Major Endocrine OrgansBrain Hypothalamus
Pituitary Anterior Posterior
Thyroid
Parathyroid
Pancreas Islets of Langerhans
AdrenalCortex Medulla
Kidney
OvaryCorpus LuteumFollicle
Placenta
Hypothalamic-Pituitary Portal System
Hypothalamic-Pituitary Axis
Hypothalamus
AnteriorPituitary
CRF
ACTHGluc
ocor
ticoid
s
AdiposeLipolysis
LiverGluconeogenesisInhibit Insulin Action
MuscleProtein Breakdown
MammaryLactogenesisLactation
AdrenalCortexMedulla
Kidney
Hypothalamus
AnteriorPituitary
TRH
TSH
Thyroxin
IncreasedBasalMetabolicRate
Thyroid
Cold
Temperature Regulation
Hypothalamus
AnteriorPituitary
GnRH
FSH
FolliclesGrowth
Follicular Development
Mammary GlandDuct GrowthIncreased Progesterone Receptor
BrainSexual Behavior
UterusGrowth
Estroge
n
Hypothalamus
AnteriorPituitary
GnRH
LH
FollicleOvuation
Ovulation
Mammary GlandAlveolar Growthtogether with estrogen
Estrogen + Progesterone
Corp
us lu
teum
fo
rmati
on
Corpus luteum
Estrogen
BrainSexual Behavior
UterusMaintains Pregnancy
Estro
gen +
Proge
stero
ne
Estrogen + Progesterone
Hypothalamus
AnteriorPituitary
GHRH SomatostatinInhibits GH
AdiposeLipolysisInhibit insulin action
MuscleProtein synthesis or Breakdown Inhibits insulin action
MammaryIncreased Nutrient uptakeIncreased blood flow.
LiverGluconeogenesisInhibit Insulin Action
Body Growth
Hypothalamus
AnteriorPituitary
TRF DopamineInhibits Prl
MammaryLactogenesis,Lactation (some Species)
CL of Most RodentsCL formationProgesterone production(LH still induces ovulation)
Intestine
Pancreas
Islets ofLangerhans
CellsGlucagon
Opposite of insulin in liver and muscle
bCells
Produce Insulin
AdiposeGlucose uptakeFat synthesis
LiverGlucose uptakeGlycogen synthesisInhibits gluconeogenesis
MuscleGlucose uptakeGlycogen synthesisAmino acid uptakeProtein synthesis
MammaryLittle effectIncreases glucose uptakeAmino acid uptake
Insulin
Brain ?Food Intake
MammaryGrowth
Various OrgansNutrient Partitioning ?Cotyledon
Fetal Placenta Produces Placental Lactogen
Caruncle
Maternal Side of Placenta
Uterus
PlacentalLactogen
21181512963000
2
4
6
8
10
12
Estrogen
Progesterone
Estrous Cycle of Cow
Day of Cycle
Hormonal Levels Estrus Cycle-Parturition
Ovary on Growth
Control OvX Ovx + E0.0
0.5
1.0
1.5
2.0
2.5End Bud AreaDuct Length
Peripuberal Mammary GrowthWeeks 3-6 in Mice
Area
(mm
Sq)
or L
engt
h (m
m)
Estrogen ActionsEndocrine
Epithelium
Cell Division
Estrogen
Estrogen ActionsParacrine
Stroma
Cell Division
Growth Factors
Estrogen
Estrogen ActionsAutocrine
Cell Division
Growth Factors
Estrogen
Estrogen Signaling
Estrogen Receptor Localization in Mammary Ducts
Steroid Hormones and Mammary Growth in Heifers
2502001501005000
10
20
30
Estrogen
Progesterone
Prolactin
Placental Lactogen
Hormone Changes During Pregnancy in Cows
Days Pregnant
Estr
ogen
(pg/
ml)
Prog
este
rone
, Pro
lacti
n, P
lace
ntl L
acto
gen
(ng/
ml)
Control E P E+P0.0
0.2
0.4
0.6
0.8
1.0
1.2
E+P on Mammary GrowthPostpuberal Mice
Epith
elia
l Vol
ume
(mm
Cu)
Additive Response
Synergy
Estrogen and Progesterone Actions
Epithelium
CellDivision
Estrogen increases progesterone receptorIncreases growth
ProgesteroneIncreases growthAlveolar formation
Autocrine and paracrine actions are similar to estrogen alone.
0 5 250
2
4
6
8
10
- E+P+ E+P
Placental Lactogen on Mammary Growth
Bovine Placental Lactogen (µg/day)
% L
abel
ed E
pith
elia
l Cel
ls
Prolactin and Growth Hormone• Variable among species– Mice
• Pituitary required for growth• Which hormone depends on strain
– Cows• Little effect of prolactin on growth• Maybe some of growth hormone
– May be indirect
• At least some effects indirect– Somatomedin (IGF-I) from liver– Nutrient partitioning
Prl and GH Action
Receptor
Hormone
ActivationDimerization
PO4
ATP
ADP
Kinase Activation
JAK2
PO4STAT
NuclearTranslocationof STAT
Transcription
Estradiol and IGF-I Effect on Mammary Growth
Hormone Levels During Late Pregnancy
Hormone Levels Around Parturition
Hormone Levels at Calving
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