Effects of different intensities of cold stress on certain physiological phenomena related to skeletal health in a hypogonadal rat model.
Intestinal transference pattern of calcium and associated changes in the activities of intestinal mucosal enzymes, rate of bone turnover and bone metabolism were evaluated in ovariectomized rats exposed to cold stress of various intensities i.e., mild (15 degrees C) or stronger (8 degrees C and 4 degrees C) for 5 min everyday for 7 consecutive days. Except mild cold stress-induced group (15 degrees C), rats of other two groups (8 degrees C and 4 degrees C) showed considerable decrease in the rate of in situ intestinal transference of calcium. Likewise, in these groups, the activities of intestinal mucosal enzymes, alkaline phosphatase (AP) and calcium ATPase (Ca2+-ATPase) were decreased significantly in all the segments of small intestine in a descending gradient. Also significant changes in bone turnover and bone resorption were confirmed in these animals by marked alterations in plasma AP activity, urinary calcium and phosphate excretion and urinary calcium to creatinine ratio (Ca: Cr). The skeletal changes were further ascertained by examining other physical and biochemical parameters of bone metabolism viz., body mass, bone density, ratio of mineral to matrix and mineral content of bone ash (calcium and phosphate) in the ovariectomized rat model. All these results suggest that stronger cold stress (8 degrees C and 4 degrees C) may be an important ecological factor in the development of earlier bone loss in hypogonadal rats.
Islam
M N
MN
Department of Physiology, Presidency College, Calcutta, India.
Chanda
S
S
Mitra
C
C
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000097:blood / Q000378:metabolism; D000818:Animals; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism / Q000503:physiopathology*; D002118:Calcium / Q000097:blood / Q000378:metabolism / Q000652:urine; D003080:Cold Temperature; D003345:Corticosterone / Q000097:blood; D003404:Creatinine / Q000652:urine; D005260:Female; D007006:Hypogonadism / Q000503:physiopathology*; D007413:Intestinal Mucosa / Q000378:metabolism; D010052:Ovariectomy; D010710:Phosphates / Q000378:metabolism / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D010710:Phosphates; D013972:Thyrotropin; D003404:Creatinine; D000469:Alkaline Phosphatase; D000251:Adenosine Triphosphatases; D013974:Thyroxine; D002118:Calcium; D003345:Corticosterone