ABSTRACT
Background: Tribulus terrestris is a creeping herb that has been used in the past for treating impotence. The extract obtained from Tribulus mainly contains the active component protodioscin. Administration of the extract improves libido and spermatogenesis. Protodioscin increases the levels of luteinizing hormone [LH], testosterone, dehydroepiandrosterone [DHEA] and dihydrotestosterone [DHT]. The objective of present study was to determine the effect of Tribulus terrestris on serum luteinizing hormone in male Sprague Dawley rats
Methods: The study was carried on 60 adult male Sprague Dawley rats aged 90-120 days and with average body weight of 200+/-50 grams. Rats were divided into two groups with 30 rats per group. Group A received 0.5 ml distilled water once daily orally. Group B was administered orally Tribulus aqueous extract 6 mg/Kg once daily. All the doses were given to rats for 8 weeks. After 8 weeks, serum luteinizing hormone was measured in both groups. The mean values of LH were compared using SPSS. Alpha value was kept at 0.05
Results: The mean LH level was 1.26+/-0.54 for control group while it was 1.75+/-0.65 for the experimental group. The difference between control group and experimental group was statistically significant [p<0.001]
Conclusion: Tribulus terrestris increases the levels of LH when administered in appropriate doses
ABSTRACT
To determine the effect of ascorbic acid supplementation on long-term cold exposure induced changes in thyroid activity in Sprague-Dawley rats. Experimental study. Physiology Department of Islamic International Medical College, Rawalpindi, National Institute of Health, Islamabad and Railway Hospital, Rawalpindi, from January to December 2009. Ninety Sprague-Dawley rats were randomly divided into three groups of control, cold exposed and cold exposed along with ascorbic acid supplementation. After one month, their thyroid levels were analyzed by using chemiluminescent immunometric Assay on Siemens Immulite 2000 Analyzer. After 4 weeks of cold exposure to experimental animals, the thyroid activity was raised significantly in the cold exposed group as compared to the control group [p-value for T[3] difference = 0.004, T[4] difference = 0.002 and TSH difference < 0.001]. Supplementation with ascorbic acid in the third group normalized the thyroid hormone activity with p-value for difference in levels of T[3] being 0.6661, T[4] = 0.027 and TSH = 0.0028. Ascorbic acid prevented the cold induced changes in thyroid hormone levels in rodents
ABSTRACT
BACKGROUND: On exposure to prolonged cold temperature, the body responds for effective heat production both by shivering and nonshivering thermogenesis. Cold exposure increases the production of reactive oxygen species which influence the sarcoplasmic reticulum Ca release from the skeletal muscles and affect their contractile properties. The role of ascorbic acid supplementation on force-frequency relationship of cold exposed skeletal muscles was evaluated in this study
METHOD: Ninety healthy, male Sprague Dawley rats were randomly divided into three groups of control [I], cold exposed [II] and cold exposed along with ascorbic acid supplementation [III]. Group II was given cold exposure by keeping their cages in ice-filled tubes for 1hr/day for one month. Group III was also exposed to cold along with ascorbic acid supplement as 500mg/L mixed in drinking water for one month. After the study period, the extensor digitorum longus muscle was dissected out and force-frequency relationship in the skeletal muscle fibers was analyzed on computerized data acquisition system
RESULTS: The group II showed a significant decline in the contractile properties of skeletal muscle fibers at different frequencies as compared to the group I [p value <0.05]. In group III, however, the force was contraction was better than group II [p value <0.05]
CONCLUSION: Ascorbic acid prevents the decrease in force of contraction in muscles exposed to chronic cold
ABSTRACT
Background: On exposure to prolonged cold temperature, the body responds for effective heat production both by shivering and non-shivering thermogenesis. Cold exposure increases the production of reactive oxygen species which influence the sarcoplasmic reticulum Ca++ release from the skeletal muscles and affect their contractile properties. The role of ascorbic acid supplementation on force of contraction during fatigue of cold exposed skeletal muscles was evaluated in this study. Method: Ninety healthy, male Sprague Dawley rats were randomly divided into three groups of control [I], cold exposed [II], and cold exposed with ascorbic acid 500 mg/L supplementation mixed in drinking water [III]. Group II and III were given cold exposure by keeping their cages in ice-filled tubs for 1 hr/day for one month. After one month, the extensor digitorum longus muscle was dissected out and force of contraction during fatigue in the skeletal muscle fibres was analysed on a computerised data acquisition system. Results: The cold exposed group showed a significant delay in the force of contraction during fatigue of skeletal muscle fibres compared to control group. Group III showed easy fatigability and a better force of contraction than the cold exposed group. Conclusions: Ascorbic acid increases the force of contraction and decreases resistance to fatigue in the muscles exposed to chronic cold