A comparative study of plasma renin activity, aldosterone and atrial natriuretic hormone between normotensive and hypertensive people living at below sea level altitude (Jordan Valley) and those residing at moderate altitude above

A cross-sectional study was designed to investigate the association of the levels of plasma renin activity (PRA) and aldosterone (ALDO) and atrial natriuretic hormone (ANH) with the rates of hypertension prevalence in people living at 340 meters below sea level, the Jordan Valley (JV) and those residing at 620 meters above sea level, Irbid City. 1072 natives from the JV and 1402 natives from Irbid City were covered by a questionnaire to estimate hypertension prevalence in the JV and Irbid city (population age: 35-65 years). Male subjects were selected from the JV (24 hypertensives, 46+/-15 years old, and 93 normotensives, 33+/-13 years old) and from Irbid City (31 hypertensives, 47+/-12 years old, and 89 normotensives, 40+/-13 years old) to evaluate the levels of PRA, ALDO and ANH. Hypertension was less common in the JV than in Irbid City (9.9% vs. 13.6%). The levels of PRA in the hypertensive subjects compared to the normotensive subjects were lower in the JV (1.7+/-1.0 vs. 2.6+/-1.4 ng/ml/hr) but were similar in Irbid City (2.9+/-2.7 vs. 3.2+/-2.7). The levels of ALDO in the hypertensive subjects compared to the normotensive subjects were similar in the JV (119+/-58 vs. 139+/-66 pg/ml) but were higher in Irbid City (199+/-112 vs. 146+/-84). The levels of ANH in the hypertensive subjects compared to the normotensive subjects were lower in the JV (13.9+/-9.3 vs. 28.0+/-12.7 ng/ml) and were also lower in Irbid City (21.0+/-12.2 vs. 26.7+/-11.6).     

Allopurinol Enhances Adenine Nucleotide Levels and Improves Myocardial Function in Isolated Hypoxic Rat Heart

Allopurinol, a competitive inhibitor of xanthine oxidase, was found to have a protective effect on ischemic myocardium. Its mechanism of action is still controversial. We used Langendorff isolated rat heart preparation to test the hypothesis that allopurinol could maintain a level of the adenine nucleotide pool (ATP, ADP, and AMP) that would protect and improve the functional activity of the heart during a period of hypoxia. Hearts were initially perfused for 30 min until steady state was attained. This was followed by 20 min of experimental perfusion divided into 5 min of control perfusion followed by 15 min of hypoxic perfusion with or without allopurinol in the perfusate. Hearts were quick-frozen and enzymatically analyzed for adenine nucleotides and creatine phosphate at the end of the hypoxic period. Left ventricular pressure, heart rate, and coronary flow were measured in all preparations. Allopurinol (0.1 mM) treated hearts had greater levels of ATP (12.3 ± 0.8 vs. 9.3 ± 0.8 µmol/g dry weight; p < 0.01). This improvement occurred in the presence as well as the absence of glucose. Total adenine nucleotides improved from 17 ± 1 to 20.3 ± 2.4 µmol/g dry weight (p < 0.01). This improvement also occurred in the presence as well as in the absence of glucose in the perfusate. It also improved cell energy state significantly in the presence as well as the absence of glucose. There was insignificant change in creatine phosphate. Allopurinol improved left ventricular pressure from 38 ± 7% to 55 ± 9% (p < 0.002) in the presence of glucose and from 8 ± 3% to 27 ± 6.3% (p < 0.001) in the absence of glucose. Coronary flow improved from 110 ± 5% to 120 ± 8% (p < 0.04) in the presence of glucose. These results support the suggestion that allopurinol at 0.1 mM exerts its protective effect on rat heart during hypoxia by enhancing the adenine nucleotide pool.     

Lactate Dehydrogenase Activity and Insulin and Lactate Levels at an Altitude Below Sea Level (–350 m) Compared to Those at an Altitude Above Sea Level (620 m) After Exercise

This study was designed to investigate the effect of exercise at 350 m below sea level altitude (–350 m) on the serum levels of lactate dehydrogenase (LDH), insulin, and lactate. The study was carried out on ten trained adult males with mean age of 23.3 ± 3.4 years following a 21-km noncompetitive run. Venous blood was withdrawn from the subjects before exercise and 5 min post exercise. For comparison purposes, a similar study was performed with the same subjects but at 620 m above sea level (+620 m). The results show a significant increase in LDH and lactate levels after exercise only at low altitude (–350 m). Serum insulin levels decreased significantly after exercise at both altitudes. These changes in serum levels of LDH, insulin, and lactate at different altitudes suggest that a type of metabolic adjustment is present that meets energy requirements during exercise.     

Clinico-hormonal correlation of oligospermic patients in the below sea level environment (Jordan Valley)

A correlation between serum levels of luteinizing hormone (LH), total testosterone (T), free T and sex-hormone binding globulin (SHBG) in normospermic and in oligospermic male people was done. This study was designed to measure serum levels of these hormones and of SHBG in people living at different altitude environments relative to sea level: at 209-408 meters below (the Jordan Valley, JV) and at 620 meters above (Irbid city, IC). In addition, a clinical awareness study of oligospermia was done in the North of Jordan (IC). Seminal analysis in 287 male people (age range, 18 to 40 years old) during the period between 12/6/1999 and 12/2/2002 showed an oligospermia of 31.4%. Serum levels of LH, total T, free T and SHBG in normospermic subjects in IC were similar to those in normospermic of the JV (3.4 +/- 1.2 vs. 4.0 +/- 1.7 MIU/ml, 19.9 +/- 4.0 vs. 20.4 +/- 5.6 ng/ml, 53.9 +/- 15.6 vs. 47.9 +/- 10.7 pg/ml, 19.5 +/- 3.2 vs. 18.6 +/- 2.16 nmol/l, respectively). Oligospermia was associated with increase in total T at both IC (27.5 +/- 4.6 vs. 19.9 +/- 4.0 ng/ml) and the JV (30.7 +/- 3.4 vs. 20.5 +/- 5.6). The higher serum level of total T in oligospermic people in both IC and the JV was associated with higher levels of SHBG compared to those levels in normospermic subjects. On the other hand, oligospermic subjects have lower serum level of free T than in normospermic males (41.5 +/- 10.0 vs. 53.9 +/- 15.6) only in IC, while in the JV, serum free T level was similar (46.5 +/- 6.1 vs. 47.9 +/- 10.7). Taken together data for both locations, IC and the JV, suggest a clear correlation between total T and SHBG levels in both groups' normospermic and oligospermic subjects.     

Plasma levels of adrenocorticotropic hormone and cortisol in people living in an environment below sea level (Jordan Valley) during fasting in the month of Ramadan

OBJECTIVES: To investigate the effects of Ramadan fasting on plasma levels of ACTH and cortisol in athletic students living in the Jordan Valley (JV) and compare them to those living at above sea level in Ramtha City (RC). METHODS: Sample collection and measurements were done in November 1998 from non-fasting and in December 1998 from fasting people. RESULTS: ACTH levels in non-fasting subjects in the JV were 36 +/- 4 IU/ml compared to 43 +/- 3 IU/ml for those in RC. Cortisol levels were 483 +/- 76 (JV) and 539 +/- 89 nmol/l (RC). Fasting led to an increase in ACTH (49 +/- 6 (JV) and 58 +/- 5 IU/ml (RC)) and cortisol levels (637 +/- 101 (JV) and 805 +/- 72 nmol/l (RC)). CONCLUSION: Fasting increases ACTH and cortisol levels in an altitude-independent fashion.