Tsai C L, Wong T Y, Tsai S C, Lau C P, Chen Y Z, Hwang G S, Wang P S
Department of Orthopaedic Surgery, College of Medicine, National Taiwan University, Taipei, Republic of China.
Chin J Physiol. 1991;34(4):455-62.
The effects of aging on the concentration of plasma calcium and urinary calcium excretion in response to human calcitonin (hCT) were investigated in rats. Old (23 months) and young (5 months) female rats were housed individually in metabolic cages. Daily urinary samples were collected over 3 days prior to the hCT injection, and at the 2nd and the 26th hr following the hCT injection. All rats were catheterized via the right jugular vein before a single intravenous injection of hCT (40 ng/kg). Blood samples were collected from the jugular catheter before and after the hCT injection. The basal level of urine flow and calcium excretions were greater in old than in young female rats. The hCT injection significantly decreased the plasma calcium concentration in young female rats, compared to old female rats at 10, 30, and 60 min after the injection. Two hrs after hCT injection, the urinary calcium concentration decreased greater (p less than 0.01) in young than in old female rats. These findings suggest that the reduction of the hypocalcemic and hypocalciuric effects of CT in female rats was age-associated.
研究了衰老对大鼠血浆钙浓度以及尿钙排泄量（对人降钙素（hCT）的反应）的影响。将老年（23个月）和年轻（5个月）雌性大鼠单独饲养在代谢笼中。在注射hCT前3天以及注射hCT后的第2小时和第26小时，每天收集尿样。在单次静脉注射hCT（40 ng/kg）前，所有大鼠均经右颈静脉插管。在注射hCT前后，从颈静脉导管采集血样。老年雌性大鼠的尿流量和钙排泄的基础水平高于年轻雌性大鼠。与老年雌性大鼠相比，注射hCT后10、30和60分钟时，年轻雌性大鼠的血浆钙浓度显著降低。注射hCT两小时后，年轻雌性大鼠的尿钙浓度下降幅度大于老年雌性大鼠（p<0.01）。这些发现表明，雌性大鼠中CT降钙和降尿钙作用的降低与年龄相关。
