Deficit - infertility in adult life - lack of sexual maturation
Excess - precocious puberty at age 4/5
Feedback loops
Short feed back loop - anterior pituitary inhibits hypothalamus e.g. GH and PRL
Long feedback loop - endocrine gland inhibits both anterior pituitary and hypothalamus e.g. cortisol, IGF and testosterone
Actions of oxytocin
Contraction of uterine muscle in childbirth
Milk ejection by contraction of breast myoepithelium
Role in social behaviours and parental behaviours due to release in brain
Trust hormone
Hypothalamo-pituitary-adrenal axis
Stress e.g. infection, pain etc stimulates hypothalamus to secrete corticotrophin releasing hormone
Anterior pituitary corticotroph cells release ACTH
Adrenal cortex secretes cortisol
Long feedback loop
Development of the pituitary
Downgrowth from developing hypothalamus - neural ectoderm - posterior pituitary
Upgrowth of oral ectoderm from roof of mouth - anterior pituitary
Development directed by different transcription factors for each section
Control of growth hormone
Metabolites, sleep, stress and exercise trigger hypothalamus to secrete growth hormone releasing hormone
Anterior pituitary somatotroph cells release growth hormone
Short feedback loop
GH acts directly + via liver IGFs to induce bone and muscle growth
ACTH
A polypeptide hormone from POMC precursor - secreted by corticotroph cells
GPCR coupled to cAMP
Stimulates secretion of cortisol from adrenal cortex in stress
Stimulates growth of adrenal cortex
Gonadotrophins - LH and FSH
Used for reproduction
Women - act in ovary via GPCR - FSH for follicle development and LH for ovulation and progesterone production
Male - act in testes - LH for testosterone production and FSH for sperm production
