“…We have no direct evidence that PTHrP of parathyroid origin regulates placental calcium transport in the pig, as it does in the sheep (Rodda et al 1988;Abbas, Pickard, Rodda, Heath, Hammonds, Wood, Caple, Martin & Care, 1989;Care, Abbas, Pickard, Barri, Drinkhill, Findlay, White & Caple, 1990), but PTHrP derived from the placenta itself may have a local action on calcium transport to the fetus. Thyroparathyroidectomy of the ovine fetus, with thyroxine replacements, results in reversal of the placental calcium gradient (Care, Caple, Abbas & Pickard, 1986).…”