36. Which of the following vasoactive factor is NOT produced by endothelial cells ? (A) NO (B) Atrial natriuretic peptide (C) Prostacyclin (D) Endothelin-1.

23. A lower-than-normal concentration of plasma calcium causes (A) a decrease in bone resorption (B) a decrease in the urinary excretion of calcium (C) a decrease in the secretion of parathyroid hormone (PTH) (D) a decrease in vitamin D release from the skin