The Effect of Prolonged Strain on Serum Levels of Human Pancreatic Polypeptide and Group I Pepsinogens

Abstract

Twenty-four young male subjects participated in a 5-day training course with long-term physical exercise (35% of VO_2max), calorie supply deficiency (intake of approximately 6300 kJ/24 h, against a combustion of approximately 40,000 kJ/24 h), and severe sleep deprivation (2 h of sleep as a total during 5 days). The subjects were divided into three groups; one group (no. = 7) had no compensation for the stress factors, another group (no. = 8) compensated for the calorie deficiency, whereas a third group (no. = 9) partly compensated for the sleep deprivation. Fasting serum concentration of human pancreatic polypeptide (hPP) and group I pepsinogens (PGI) were measured immediately before the course, every morning during the course, and 8 h after the course. In addition, the serum response of hPP to a test meal was measured on day 3 during the course and in a control study performed 8 weeks later. The fasting serum concentration of hPP showed a two- to three-fold increase during the course in the low-caloric but not in the iso-caloric subjects. The serum concentration of hPP was decreased to pre-course levels after 8 h of rest. The postprandial hPP response was elevated in all the subjects during the course, with a greater increase in the low-caloric subjects than in the subjects with calorie balance. Serum concentration of PGI was 10-30% decreased during the course, and the levels were normalized after 8 h of rest after the course. The study shows that the function of the hPP cell and the chief cell is influenced by prolonged, multifactorial strain. Especially calorie deficiency appears to affect the release of hPP.

Key-words:

• Exercise, physical
• human pancreatic polypeptide
• group 1 pepsinogens
• sleep, deprivation
• starvation