Concentrations of glucose, lactic acid, free fatty acid (FFA), insulin, cortisol and growth hormone (GH) in the blood were monitored in 15 euglycaemic men (sojourners, SJ) at sea level (SL) and while at altitudes of 3500 m and 5080 m, in acclimatised low landers (ALL) and in high altitude natives (HAN). In SJ, blood glucose and insulin concentrations showed a significant increase on the 3rd and 7th day after arrival at high altitude (HA), thereafter returning to sea level values and remaining the same during the entire period of their stay at 3500 m. Subsequently, on arrival at higher altitude (5080 m) the glucose concentrations again showed an increase over the preceding values and returned to SL values on day 41 while at 5080 m. A significant increase in cortisol concentrations was seen on day 3 after arrival at HA and the increased levels were maintained until day 21 at 3500 m. The cortisol concentrations on day 30 after arrival at 5080 m came down to SL values and remained unchanged thereafter. No appreciable change in GH and FFA was seen during the sojourn at HA. On the other hand, blood lactic acid concentration decreased significantly. There was no difference between the fasting glucose concentrations in ALL at 3500 m and in HAN at 3500 m and 4200 m compared to values of SJ at SL, whereas ALL at 4200 m had higher glucose values. Concentrations of plasma insulin and GH in ALL and HAN were higher than the values of SJ at SL, whereas cortisol values did not show any difference. These observations indicated that at HA the glucose values were high for the insulin concentration observed and might have been due to increased secretion of GH by the pituitary gland.

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Altitude induced alterations in circulatory levels of PRL, LH, FSH and testosterone were studied in seven eugonadal men at sea level (SL), during their stay at high altitude (HA, 3500 m) and a week after return to SL. The mean plasma PRL level at SL was 5.83 k 1.7 SE ng/ml. On day one and seven of arrival at HA, the PRL values of 7.81 k 1.8 1 and 9.2 1 f 1.64 ndml respectively were not significantly different (p > 0.05) than the initial SL values. However, on day 18 of stay at HA, PRL levels were significantly increased (p < 0.01) to 17.68 k 1.82 n g / d and returned to initial SL values within seven days of return to SL. A significant decrease (p < 0.01) in LH and testosterone was observed on seventh day of stay at HA and the decreased levels were maintained till day 18 of observations. Plasma testosterone returned to the initial SL values within a week of return to SL, whereas LH levels remained significantly lower (p < 0.01). The FSH levels did not show any significant change during their stay at HA or after return to SL. These observations suggest that exposure to altitude is associated with hyperprolactenemia and an impaired pituitary gonadal function. The decreased levels of LH and testosterone at HA could either be due to hypoxic stress per se or secondary to altitude induced hyperprolactenemia. Hormon-Profile beim Mann in groRer HoheZusarmnenfassung: Bei sieben gesunden Mannern mit normaler Hodenfunktion wurde der EinfluB groBer Hohe auf die zirkulierenden Werte von PRL, LH, FSH und Testosteron untersucht. Hierzu wurden diese Probanden zunachst in ein Seeklima (226 m) und dann in ein Hohenklima des Himalaya (3500 m) verbracht. Es ergab sich, daB die PRL-Werte signifkant anstiegen und sieben Tage nach der Riickkehr wieder normal waren. Fur LH und Testosteron wurde ein signifikanter Abfall im gleichen Zeitraum geobachtet, der fur LH langsamer zur Norm zuriickkehrte als es fur Testosteron zutraf. FSH zeigte demgegenuber keine signifkante Xnderung.Diese Beobachtungen belegen, d& der Aufenthlat in g r o k r Hohe mit einer Hyperprolaktinamie und einer gestorten Funktion der Hypophysen-Gonaden-Achse einhergeht. Der Abfall der LH-und Testosteron-Werte kann sowohl auf die Hypoxie als auch sekundar durch die hohenbedingte Hyperprolaktinamie bedingt sein.

No abstract

The normal blood glucose level of Channa punctatus undergoes a seasonal change. A post‐spawning hyperglycemia is found during August, September, October and November. Fish kept out of water show increase in blood glucose level upto 24 hours. When returned to water, the asphyxial hyperglycemia subsides after 24 hours. Starvation does not appear to affect the blood glucose in this fish.