Effect of short- and long-term stress on plasma calcium and calcitonin in the rat.

Abstract

Although hypocalcemia has been observed during stress, the cause(s) is still unknown. The effect of short- and long-term restraint stress on calcitonin (CT) secretion and on plasma calcium (Ca), inorganic phosphate (P), total protein (TP), and corticosterone (CORT) were investigated in the male and female Sprague-Dawley rat. The rats were restrained in the supine position for two hours/day for either one day (STS) or for 14 days (LTS), and compared to normal controls (CON). Plasma Ca levels in both STS and LTS rats were significantly lower and mean plasma CORT levels in female stressed rats were significantly higher than those in sex-matched CON rats. However, mean basal levels of plasma CT did not differ among these three groups for either sex. Similarly, mean increment of plasma CT after Ca infusion (Ca 10 mg/100 g, i.v.) did not differ between STS or LTS rats and CON rats. These data reveal no causal relationship between CT and the hypocalcemia during either short-or long-term stressful stimuli.