Effect of exposure to the altitude of 300 meters below sea-level on testosterone, luteinizing hormone, follicle-stimulating hormone and prolactin in man.

Serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) responses to exposure to sea-level altitude (LA) were examined in 13 eugonadal males, age 21-22 yr, 3 and 5 days after residing at LA and on the second day of return to basal altitude 90 days later. After 3 days at their respective residence altitude, there was elevation in LH (p less than 0.05) and depression in testosterone levels (p less than 0.05), with similar results on day 5. These effects were all of transient nature, LH and testosterone concentrations returned to their basal levels on second day of the return to basal altitude. The FSH and PRL levels did not show any significant change during the stay at LA or after return to basal altitude. The observations suggest that exposure to LA is associated with increase in plasma levels of LH and decrease in testosterone. The decreased levels of testosterone could be due to a reduction in the sensitivity of the testis to LH, or due to inhibition of steroidogenesis in the testis.