PTH and Hypocalcemia: Regarding the effect of HSD on calcium metabolism, besides being a factor that induced fecal calcium loss, HSD was previously reported to enhance urinary calcium excretion and induce hypocalcemia, the latter of which consequently activated the secretion of parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] [21, 22].