Vasodilatory properties of parathyroid hormone-related protein in the mammary gland of the lactating goat

C.G. Prosser, S.R. Davis, V.C. Farr

Dairying Research Corporation, Private Bag 3123, Hamilton, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1993, 53: 139-142

Human synthetic parathyroid hormone-related protein (PTHrP) increased mammary blood flow (MBF) following close-arterial infusion via the external pudic artery of lactating goats. MBF increased 74 ą 8% within 30 min of the start of continuous infusion of PTHrP compared with 10 ą 3% from control. However, by 90 min MBF decreased and was not different from control for the remainder of the infusion. Elevation in plasma concentrations of calcium and decrease in phosphate during PTHrP suggests this was not due to altered activity of PTHrP, but may relate to down- regulation of response or production of counter-regulatory vasoconstrictive agents within the gland. However, this problem can be alleviated when PTHrP is infused in a pulsatile fashion. Thus, PTHrP may be usefully employed in studies designed to raise MBF during lactation.

Keywords: NZSAPAB; PTHrP; mammary blood flow; goats.

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Last Updated 25-01-1997