Table 1

Major reproductive and metabolic hormones influencing mammary gland function in pregnancy and at the onset of lactation

HormoneRole in pregnancyRole at the onset of lactationReferences
Reproductive
 ProlactinLobuloalveolar formation
Milk synthesis		Tight junction formation
Milk synthesis		16 19 20 26 27
 ProgesteroneMammary ductal branching
Lobuloalveolar formation		Withdrawal of progesterone initiates tight junction formation and increases milk synthesis16 28 29
 OestradiolMammary ductal branching
Lobuloalveolar formation		Not known13
Metabolic
 CortisolLobuloalveolar formation
Milk synthesis		Tight junction formation17 26
 InsulinLobuloalveolar formation
Milk synthesis		Milk synthesis15 21 30
 Growth hormone/IGF-1Lobuloalveolar formationNot known12 14

  • IGF-1, insulin-like growth factor.