PTHLH and Hypocalcemia: Nonstandard abbreviations used: 1,25(OH)2D3 = 1,25-dihydroxyvitamin D; 5-HT = serotonin; 5-HTP = 5-hydroxy-l-tryptophan; CON = control group; EGTA = ethylene glycol tetraacetic acid; iCa = ionized calcium; MG = mammary gland; PTH = parathyroid hormone; PTHLH = parathyroid-hormone-like hormone; SCH = subclinical hypocalcemia; WB = whole blood.