[show abstract][hide abstract] ABSTRACT: The study involved three ethnic groups of India; Rajputs, Gorkhas and South-Indians. Each group consisted of ∼40 healthy, male soldiers between 20-50 years. The reference ranges for cortisol, testosterone, prolactin, arginine vasopressin and proAtrial natriuretic peptide(1-98) were determined using Enzyme-Immunoassay (EIA) while plasma levels of thyroid-stimulating hormone, triiodothyronine, free-triiodothyronine, thyroxine and freethyroxine were measured using Enzyme-linked immunosorbent assay (ELISA). The results indicated that plasma hormone concentrations were within physiological range and inter-ethnic differences were most prominent between north- (Rajputs and Gorkhas) and south- Indians. In comparison to Radioimmunoassay, the EIA method for prolactin, thyroid-stimulating hormone, free-thyroxine gave higher values while the ELISA method for triiodothyronine, free-triiodothyronine, and thyroxine gave lower values. These differences are due to differences in assay standards and design.
Indian Journal of Clinical Biochemistry 04/2010; 25(2):153-7.
[show abstract][hide abstract] ABSTRACT: Acclimatization to high altitude (HA) is accompanied by decrease in plasma atrial natriuretic peptide (ANP). On the other hand, circulating levels of the hormone are known to be influenced by age and ethnicity. The impact of these factors on ANP response during prolonged HA exposure remains unexplored. Hence, this study was conducted to examine possible age and ethnic variation in plasma proANP(1-98) levels in men after 3 to 4 weeks at HA.
Lowlanders (LL) were studied at sea level (SL) and after 3 to 4 weeks at an altitude of approximately 4500 m. The LL group comprised Rajput (n = 48), Gorkha (n = 40), and South Indian (n = 43) ethnicities. Another group of HA natives (Ladakhi, n = 40) were studied at approximately 4500 m only. Subjects were between 20 and 50 years of age. Estimation of plasma proANP(1-98) and biochemical, hematologic, and physiologic evaluation was done.
In LL at HA, proANP(1-98) levels decreased (P < .001); plasma arginine vasopressin decreased (P < .05 in Rajputs and South Indians); and total protein, hemoglobin, and hematocrit increased (P < .05). Heart rate increased (P < .05), whereas arterial oxygen saturation decreased (P < .05) in all LL at HA. Ethnicity but not age variation in proANP(1-98) was observed under HA stress. In HA natives, plasma proANP(1-98) was higher than LL at HA and did not exhibit any age variation.
Plasma proANP(1-98) levels, reflecting medium-term ANP secretion, decrease during prolonged exposure to HA in LL. This is due to diuresis leading to plasma volume reduction that occurs during the acclimatization process. Ethnicity but not age variation is associated with plasma proANP(1-98) under HA stress.
Wilderness and Environmental Medicine 03/2010; 21(1):11-6. · 1.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hormonal changes during high-altitude (HA) exposure are important for normal adaptation to the new environment in lowlanders. Prolactin (PRL), a stress hormone, is involved in the regulation of fertility, immune response, osmotic balance, and angiogenesis. However, little is known about the effect of age and ethnicity on plasma PRL changes in men during prolonged HA exposure. The aim of this research was to examine possible age and ethnic variation in plasma PRL levels in men after 3 to 4 weeks of stay at HA (approximately 4500 m) in the Indian population. Lowlanders of Rajput (n = 49), Gorkha (n = 70), and South Indian (n = 40) ethnicities were studied at sea level (SL). They were taken to an altitude of approximately 4500 m where they stayed for 3 to 4 weeks. Another group of HA natives (Ladakhi, n = 65) was studied at similar altitude. Subjects were between 20 to 50 yr of age. At HA, plasma PRL showed a decrease in Rajputs and Gorkhas (p < 0.05), whereas there was an increase (p < 0.05) in South Indians when compared to SL. There was no age variation in PRL. PRL levels in HA natives were within the SL normal range observed in lowlanders. PRL response to HA stress in lowlanders is influenced by ethnicity. The exact cause for such differences in PRL secretion under HA stress is not clearly known. Further studies on the physiological regulation of PRL at HA are needed.
High altitude medicine & biology 01/2009; 10(4):343-8. · 1.58 Impact Factor