Alterations in mammary-gland blood flow and glucose metabolism in the lactating rat induced by short-term starvation and refeeding.

Six-hour starvation of lactating rats caused a 75% decrease in mammary-gland lipogenesis. The inhibition of lipogenesis was accompanied by a 45% decrease of blood flow to the mammary gland and a 60% decrease in glucose uptake. Within 2 h of refeeding, lipogenesis and glucose uptake by the gland increased to fed values though blood flow to the gland remained at only 63% of that in the fed state. It is concluded that blood flow, and hence substrate supply, is not a rate-limiting factor for lipogenesis by the lactating mammary gland in the rat.