Bihar Veterinary College Bihar Animal Sciences University Patna Progesterone and estrogen stimulate proliferation of secretory tissues In vivo sequential addition of insulin glucocorticoid ID: 935202
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GALACTOPOIESISDr Pramod KumarBihar Veterinary CollegeBihar Animal Sciences University Patna
Slide2Progesterone and estrogen stimulate proliferation of secretory tissues. In vivo, sequential addition of insulin, glucocorticoid and prolactin leads to biosynthesis of casein and lactose. Progesterone inhibits differentiation of secretory cells. Sensitivity of individual cells to progestational inhibition may decrease variably which may be interdependent upon relative increases in estrogen, prolactin, corticoids and growth hormone to cause asynchronies at calving.
Slide3Galactopoiesis (maintainance of lactation)ProlactinGHCortisolPTHInsulinOxytocin
Slide4Ejection of Milk: OxytocinMilk let down reflex or suckling reflexNeuroendocrine reflexSuckling of teatsAfferent conduction of APs
spinal cord
hypothalamus
Prolactin
secretion
Oxytocin
secretion
Increase
milk
in the alveoli
Contraction of the myoepithelial cells
Ejection of milk
Slide5Role of hormonesEstrogen & Progesterone specific effect of both these hormones is to inhibit the actual secretion of milkProlactin: stimulates milk productionOxytocin: stimulates milk releaseHuman chorionic somatomammotropin: lactogenic properties and support action of prolactin