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Biomedical subjects

O Oktedalen

Publications and source records attributed to O Oktedalen.

26 records · Page 2Linked to original sources
PubMed1984

The thyroid function in young men during prolonged exercise and the effect of energy and sleep deprivation.

Thyroid function has been investigated in 24 young military cadets participating in a 5 d ranger training course with heavy physical exercise, calorie deficiency and deprivation of sleep. The cadets were divided into three groups, each differing in the amount of sleep and food consumption. The serum levels of thyroid hormones (T4, FT4, T3, rT3) and TBG showed a biphasic pattern during the course. Initially there was an increased secretion concomitant with an increased deiodination of T4 to T3 and rT3 mainly due to physical exercise. When the activities lasted for several days without sufficient food supply the thyroid secretion decreased simultaneously with an alteration of the peripheral conversion of T4 to rT3 instead of T3. A significant correlation was found between the changes in total and free thyroxine (r = 0.9) and between the increase in rT3 and decrease in T3 (r = 0.6). TSH decreased during the first day of activities and remained low throughout the course. The TSH response to TRH stimulation was greatly reduced during the course due to physical exercise and calorie deficiency. The present investigation demonstrates that the thyroid function is strongly affected by prolonged physical exercise and a negative energy balance, whereas sleep deprivation does not have any significant influence. The results indicate that the alteration observed is not regulated just by the hypothalamo-pituitary-thyroid-axis alone.

Adult↗
PubMed1984

The effect of physical stress on gastric secretion and pancreatic polypeptide levels in man.

Twelve healthy subjects were exposed to a 4-day period of hard physical exercise, calorie supply deficiency, and severe sleep deprivation. The basal acid output (BAO), the sham-feeding-induced acid output (MAOsh), and the pentagastrin-stimulated acid output (MAOpg) were measured immediately after this stress period and in a control experiment performed several weeks later. The stress induced a threefold increase in the median BAO and an increase (p less than 0.05) in the MAOsh, which, however, was not significantly elevated when basal-subtracted. MAOpg was unchanged. In contrast to acid, pepsin output was not influenced by stress. The human pancreatic polypeptide (hPP) level in serum increased twofold after the stress. The integrated hPP response induced by modified sham feeding was higher (p = 0.02) after the stress than in the control experiment. The results show that physical stress has separate influence on the gastric secretion of acid and pepsin.

Adult↗
PubMed1984

Responses of vasoactive intestinal polypeptide, secretin, and human pancreatic polypeptide to glucose during fasting.

The plasma concentrations of vasoactive intestinal polypeptide (VIP) and secretin and the serum concentration of human pancreatic polypeptide (hPP) were measured in nine healthy subjects during a 4-day fast. The fast induced a considerable increase in the concentrations of VIP and secretin but only a small increase in the concentration of hPP. The intravenous infusion of 50 g glucose and the oral ingestion of 50 g glucose temporarily suppressed the high concentrations of VIP and secretin. Conversely, hPP responded with a slight decrease in blood concentration after the intravenous infusion and with a modest increase after the oral ingestion. The study shows that glucose suppresses the high blood concentrations of VIP and secretin during starvation independent of the route of glucose administration. In addition, the results indicate that the blood concentration of hPP is not directly related to the blood glucose concentration during prolonged fasting.

Administration, Oral↗
PubMed1983

The plasma concentrations of secretin and vasoactive intestinal polypeptide (VIP) after long-term, strenuous exercise.

Twelve subjects (aged 21-38 years) participated in a 90-km cross-country ski race lasting 4.45-6.50 h. In order to investigate a metabolic role for secretin and vasoactive intestinal polypeptide (VIP) during long-term strenuous exercise, seven of the subjects were given an oral hypertonic glucose solution while the others had no nutrient intake immediately after the race. The plasma concentrations of secretin and VIP were greatly increased immediately after the race, and the levels were not normalized within 140 min, though there was a significant decrease after 80 min with rest. The post-race plasma levels of secretin and VIP showed a rapid and very marked decrease 15 min after ingestion of glucose, and the plasma levels had returned to control levels 60 min and 15 min respectively after glucose loading. The results indicate some metabolic function for secretin and VIP during long-term physical exercise.

Adult↗
PubMed1983

The fasting levels and the postprandial response of gastroenteropancreatic hormones before and after prolonged fasting.

The effect of a prolonged 5-day fast on the blood concentrations of vasoactive intestinal polypeptide (VIP), secretin, human pancreatic polypeptide (hPP), gastrin, and group I pepsinogens (PG I) was studied in 11 healthy subjects. During the fast there was a marked increase in the concentrations of VIP, secretin, and hPP, whereas the rise in the concentrations of gastrin and PG I was less pronounced. Refeeding suppressed the increased concentration of VIP and caused elevated postprandial concentrations of secretin and hPP, whereas starvation did not influence the postprandial release of gastrin and PG I. The study shows that prolonged starvation has a pronounced effect on gut endocrine responses.

Adult↗
PubMed1983

The effect of prolonged strain on serum levels of human pancreatic polypeptide and group I pepsinogens.

Twenty-four young male subjects participated in a 5-day training course with long-term physical exercise (35% of VO2max), 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Plasma concentration of vasoactive intestinal polypeptide during prolonged physical exercise, calorie supply deficiency, and sleep deprivation.

Twenty-four military cadets went through a 5-day period of heavy physical exercise (35% of max O2 uptake), severe calorie supply deficiency (about 36,000 kJ/24 h), and sleep deprivation (2 h of sleep as a total during 5 days). Some cadets compensated for the caloric deficiency, whereas others partly compensated for the sleep deprivation. Fasting and meal- and glucose-induced changes in the plasma concentration of vasoactive intestinal polypeptide (VIP) were measured on separate days during the course and 8 h after the course was finished (day 6). Fasting plasma concentration of VIP increased two- to five-fold during the course, with the highest increase on day 2. The calorie-compensated subjects showed a smaller increase than those who did not receive any calorie or sleep compensation. Intake of a meal or glucose solution lowered the VIP concentration in plasma within 30-60 min to the concentrations found in the control experiments performed several weeks after the course. The results indicate a role of VIP as 'a polypeptide of substrate need'.

Adult↗