Growth hormone Flashcards
what is growth hormone also known as?
Somatotropic hormone or somatotropin.
where is the growth hormone secreted from?
the anterior pituitary.
what sort of molecule is the growth hormone?
Growth hormone is a small protein that contain a single chain of 191 amino acids
how is the growth hormone released?
released in a pulsatile manner
when is the measurement of growth hormone taken?
The measurement is either done over 24-hour period or after acute stimulation using
Insulin (hypoglycaemia)
Clonidine etc.
what is growth hormone used for?
Growth hormone is essential for growth but is not the sole factor which control growth in children.
what does growth depend on?
- Genetic determination
- An adequate diet
- Freedom from chronic disease and stress
- A normal level of growth-influencing hormones such as thyroid, insulin and the sex hormones
what is the metabolic effect of growth hormone?
Increases fatty acid levels
Increases blood glucose level mainly by decreasing uptake of glucose
what does the growth hormone result in?
the growth of soft tissues and of bones
what is the growth of soft tissues accompanied by?
accompanied by both hyperplasia and hypertrophy
what makes up bone?
calcium phosphate crystals in the matrix and bone cells
what are the bone cells?
- osteoblasts
- osteocytes
- osteoclasts
what are osteoblasts?
bone forming cells
what are osteocytes?
Mature osteoblasts surrounded by organic matrix
what are osteoclasts?
Multinucleated bone breaking cells responsible for reabsorption of bone
what are the different parts of bone growth?
- epiphyseal growth
- growth in length
- growth in diameter
what is included in epiphyseal growth?
- growth in cartilage surrounding epiphysis
- cartilage ossification
- bone remodelled
what is included in the length growth?
- cartilage growth in epiphyseal plate
- cartilage ossification
- bone remodelling
- bone resorption
what are the causes of growth hormone deficiency?
Pituitary hypofunction, Lack of GHRH, Abnormal GH receptors, Lack of IGF
what are the effects of growth hormone deficiency before puberty?
Dwarfism : Short stature due to retarded skeletal growth with a plump body and poorly developed muscle
what are the treatments of growth hormone deficiency?
Replacement therapy with growth hormone of human sequence (Somatropin) produced using recombinant DNA technology
what are the effects of growth hormone deficiency after puberty?
few vague signs and symptoms
what are the causes of excess growth hormone?
a tumour of pituitary
what are the effects of excess growth hormone before puberty?
Gigantism : a well proportionate growth
what are the effects of excess growth hormone after puberty?
Acromegaly: Thickened bones and proliferation of soft tissues results in:
- Thickening of skin
- Large spade like hands
- Large tongue
- Broadening of nose
- Projection of one or both of the jaws
what is the treatment for excess growth hormone?
Surgical removal of tumour if possible
Drugs
- Somatostatin
- Bromocriptine
