GROWTH HORMONE - PowerPoint PPT Presentation

About This Presentation
Title:

GROWTH HORMONE

Description:

growth hormone d. c. mikulecky professor of physiology and faculty mentoring program growth most rapid during prenatal period juvenile period: gh is very important ... – PowerPoint PPT presentation

Number of Views:848
Avg rating:3.0/5.0
Slides: 23
Provided by: peopleVc7
Category:
Tags: growth | hormone

less

Transcript and Presenter's Notes

Title: GROWTH HORMONE


1
GROWTH HORMONE
  • D. C. MIKULECKY
  • PROFESSOR OF PHYSIOLOGY
  • AND
  • FACULTY MENTORING PROGRAM

2
GROWTH
  • MOST RAPID DURING PRENATAL PERIOD
  • JUVENILE PERIOD GH IS VERY IMPORTANT, BUT ALSO
    INSULIN AND THYROID HOMONE
  • ADOLESCENT ANDROGENS AND ESTROGENS AS WELL-SPEED
    UP GROWTH AND BRING BONE GROWTH TO A HALT

3
CONTROL OF GROWTH
  • GENETIC POTENTIAL
  • DIET
  • DISEASE
  • HORMONES

4
ANTERIOR PITUITARY HORMONES GROWTH HORMONE
(SOMATOTROPIN)
  • LIVER
  • SOMATOMEDINS
  • BONE
  • SOFT TISSUE
  • GROWTH(ABOUT 30 OF THE GENETIC POTENTIAL)
  • MANY TISSUES
  • INTERMEDIARY METABOLISM
  • INCREASE OR DECREASE

5
GROWTH HORMONE SYNTHESIS, SECRETION, AND
METABOLISM
  • ABOUT 1/6 OF THE AP CELLS
  • 5 - 10 MG STORED
  • 10X ANY OTHER PITUITARY HORMONE
  • TWO FORMS 22K AND 20K
  • BOUND TO PROTEIN IN BLOOD (SAME COMPOSITION AS
    RECEPTOR)
  • CANNOT ENTER CELL
  • DEGRADED IN TARGET CELLS AFTER UPTAKE BY RECEPTOR
    MEDIATED PROCESS

6
METABOLIC ACTIONS OF GROWTH HORMONE
  • DECREASES SENSITIVITY OF MUSCLE AND FAT CELLS TO
    INSULIN
  • SENSITIZES BETA CELLS TO SIGNALS FOR INSULIN
    SECRETION (GET PROTEIN SYNTHESIS WITHOUTDECREASE
    IN BLOOD GLUCOSE)
  • MOBILIZES TRIGLYCERIDE FAT STORED IN ADIPOSE
    TISSUE
  • CONSERVES GLUCOSE FOR BRAIN
  • DIABETOGENIC EFFECT

7
GH AND AGE
  • SECRETED THROUGHOUT LIFE
  • RATE DECREASES FROM 20-40
  • MAY ACCOUNT FOR LOSS OF BODY MASS IN THE ELDERLY
  • CHANGES OCCUR IN BOTH FREQUENCY AND MAGNITUDE OF
    SECRETIONS

8
GROWTH PROMOTING ACTIONS OF GROWTH HORMONE
  • SOFT TISSUES STIMULATES CELL DIVISION, INCREASES
    SIZE OF CELLS
  • STIMULATES ALMOST ALL ASPECTS OF PROTEIN
    SYNTHESIS
  • INHIBITS PROTEIN DEGRADATION
  • PROMOTES UPTAKE OF AMINO ACIDS

9
GROWTH PROMOTING ACTIONS OF GROWTH HORMONE
  • BONE PROMOTES GROWTH OF LONG BONES
  • THICKNESS
  • LENGTH
  • AT END OF ADOLESCENCE, SEX HORMONES STOP THIS
    ACTION

10
GROWTH HORMONE ACTS THROUGH SOMATOMEDINS
  • PEPTIDE MEDIATORS SOMATOMEDINS
  • CLOSELY RELATED TO INSULIN-LIKE GROWTH FACTORS
    IGF-I AND IGF-II
  • PRODUCED IN LIVER AND OTHER TISSUES
  • ALSO PARACRINE EFFECTS

11
REGULATION OF GROWTH HORMONE SECRETION
HIGHER BRAIN CENTERS
()
(-)
HYPOTHALAMUS
GH-RH
SST
PITUITARY
GH
SOMATOMEDINS
TARGET CELLS
12
GHRH AND GHIH
  • ANTAGONIST IN CONTROL OF GROWTH HORMONE SECRETION
  • NEGATIVE FEEDBACK
  • DIURNAL RHYTHM GH SECRETED AT NIGHT
  • EXERCISE, STRESS, HYPOGLYCEMIA

13
ABNORMAL GH SECRETION
  • DEFICIENCY DWARFISM, REDUCED MUSCLE STRENGTH,
    DECREASED BONE DENSITY
  • EXCESSGIGANTISM, ACROMEGLY

14
EPINEPHRINE, CORTISOL, AND GROWTH HORMONE
  • ALL INCREASE BLOOD GLUCOSE AND FATTY ACIDS
  • CORTISOL INCREASES BLOOD AA AND DECREASES MUSCLE
    PROTEIN
  • GH DECREASES BLOOD AA AND INCREASES MUSCLE
    PROTEIN

15
EFFECTS OF GROWTH HORMONE ON BODY COMPOSITION
  • DEFICIENCY PROMOTES HIGHER PERCENTAGE OF FAT
  • PROMOTES GROWTH OF MUSCLE, SKIN, HEART, AND MOST
    INTERNAL ORGANS EXCEPT LIVER, SPLEEN, THYROID,
    GONADS, OR REPRODUCTIVE ORGANS.

16
SYNERGISM OF GH WITH OTHER HORMONES
  • THYROID
  • INSULIN
  • GONADAL HORMONES
  • GLUCOCORTICOIDS
  • OTHER HORMONES AND GROWTH FACTORS

17
THYROID AND GROWTH
  • GROWTH STUNTED IN ABSENCE
  • EXCESS MAY STIMULATE RATE BUT NOT DRAMATICALLY
  • PROMOTE GH SYNTHESIS
  • PERMISSIVE EFFECT ON GH AT TARGETS

18
INSULIN
  • IMPORTANT DURING FETAL PERIOD IN CONTRAST TO GH
    AND THYROXINE
  • CHILDREN OF DIABETIC MOTHERS CAN BE LARGER
  • RELATED STRUCTURALLY TO THE SOMATOMEDINS
  • WITHOUT INSULIN, NORMAL RESPONSES TO GH ARE NOT
    SEEN
  • REGULATOR OF PROTEIN SYSNTHESIS?
  • REGULATOR OF ENERGY METABOLISM

19
GONADAL HORMONES ANDROGENS
  • LINEAR GROWTH BEFORE EPIPHYSIS FUSES
  • ENHANCED GH SECRETION
  • GROWTH OF MUSCLE DOUBLING OF MUSCLE MASS IN BOYS
    AT PUBERTY (SIZE AND NUMBER OF MUSCLE CELLS) (GH
    AND THYROID NOT NEEDED FOR THIS)
  • LITTLE EFFECT IN ADULT MEN WITH NORMAL TESTICULAR
    FUNCTION

20
GONADAL HORMONES ESTROGENS
  • LINEAR GROWTH BEFORE EPIPHYSIS FUSES AND BEFORE
    BREAST GROWTH (BREAST GROWTH NEEDS HIGHER LEVELS)
  • MORE COMPLICATED THAN IN MALES

21
GLUCOCORTICOIDS
  • ACUTELY GIVEN-ENHANCE GH GENE TRANSCRIPTION
  • COMPLEX EFFECTS ON GH SECRETION
  • OVERSECRETION IN CHILDREN MAY RESULT IN STUNTED
    GROWTH
  • ANTAGONIZE THE ACTIONS OF GH

22
OTHER HORMONES AND GROWTH FACTORS
  • EPIDERMAL GROWTH FACTOR
  • PLATELET-DERIVED GF
  • TRANSFORMING GROWTH FACTORS
  • FIBROBLAST GFS
  • NERVE GF
  • CYTOKINES
  • SEE TABLE 1 IN TEXT
Write a Comment
User Comments (0)
About PowerShow.com