Adrenocorticotrophic hormone stimulation of mammary secretion in lactating goats independent of increased mammary uptake of glucose.

The treatment of lactating goats with ACTH (single intramuscular injection) or cortisol (systemic infusion) resulted in an increase in milk yield and in the secretion of lactose, citrate and glucose into milk. The concentration of glucose in arterial plasma was also increased, resulting in a greater supply of glucose to the mammary gland. After ACTH treatment mammary uptake of glucose from the circulation did not increase and the balance between mammary uptake of glucose from blood and mammary output of glucose 'equivalents' into milk was significantly reduced. The results show that ACTH and cortisol can increase milk yield and lactose secretion by altering mammary metabolism of glucose.