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Biomedical subjects

A Aakvaag

Publications and source records attributed to A Aakvaag.

At least 73 records · Page 4Linked to original sources
PubMed1986

Characterization of the adenylate cyclase of the rat corpus luteum during luteolysis induced by a prostaglandin F2 alpha analogue.

Rats with superluteinized ovaries were injected with the prostaglandin F2 alpha (PGF2 alpha) analogue cloprostenol to induce luteolysis. The treatment led to decreased adenylyl cyclase response to hCG and isoproterenol in ovarian homogenates while the response to forskolin remained unchanged indicating that the catalytic unit of the enzyme was not affected by the treatment. The activation of adenylyl cyclase by Mg2+ or the non-hydrolysable guanosine triphosphate (GTP) analogue guanosine-5'-(beta,gamma-imido)-triphosphate (GMP-P(NH)P) was not altered by the treatment with cloprostenol. Both basal and hormone-stimulated adenylyl cyclase activity increased with increasing concentration of GMP-P(NH)P. Unstimulated adenylyl cyclase continuously increased with increasing concentrations of Mg2+. The same applied to forskolin. The dependence of the adenylyl cyclase stimulation by hCG and isoproterenol on Mg2+ was complex. It is postulated that PGF2 alpha induces the attenuation of ovarian adenylyl cyclase by a modification in the coupling of the hormone-receptor to the N beta-component of the adenylyl cyclase complex while the catalytic unit remains unchanged.

Adenylyl Cyclases↗
PubMed1986

Splanchnic extraction of oestrone and oestradiol and production of oestrone sulphate in man.

The plasma concentrations of oestrone (Oe1), oestradiol (Oe2) and oestrone sulphate (Oe1S) were measured in the femoral artery (FA), femoral vein (FV) and hepatic vein (HV) in seven men and three postmenopausal women undergoing catheterization for the evaluation of cardiac arrhythmias. None of the persons had congestive heart failure; conventional liver function tests were normal, and they were without any medication. The plasma concentration (mean +/- SD) for Oe1 was 34.6 +/- 19.5 pM in HV, 134 +/- 71.6 pM in FV and 93.4 +/- 48.5 pM in FA. The plasma concentration of Oe2 was 29.9 +/- 19.7 pM in HV, 80.3 +/- 42.7 pM in FV and 55.2 +/- 28.1 pM in FA. The results support the concept of peripheral formation of Oe1 and Oe2 and hepatic removal. The plasma concentration of Oe1S was 980 +/- 469 pM in HV, 945 +/- 463 pM in FV and 937 +/- 461 pM in FA. The small difference in plasma level of Oe1S between FA and FV was insignificant. In all persons the plasma level of Oe1S was higher in HV than in FA and FV (2P less than 0.01) indicating a net formation of Oe1S in the splanchnic area.

Adult↗
PubMed1985

Plasma renin activity and serum aldosterone during prolonged physical strain. The significance of sleep and energy deprivation.

Plasma renin activity (PRA), serum aldosterone and the serum and urinary levels of sodium and potassium have been investigated in 24 young men participating in a 5-day military training course with heavy continuous physical exercise, energy and sleep deprivation. The subjects were divided into three groups. Group 1 did not get any extra sleep or food, group 2 were compensated for the energy deficiency, and group 3 slept 3 h each night. The basic diet given to all the subjects was about 5,000 kJ and 2 g NaCl X 24 h-1 X cadet-1. The high calorie diet contained approximately 25,000-35,000 kJ and 20 g of NaCl X 24 h-1 X cadet-1. The study showed that serum aldosterone and PRA were extremely activated during such prolonged physical strain combined with lack of food and salt, whereas sleep deprivation did not seem to have any large influence. Only small variations were found in the serum levels of sodium and potassium and the urinary level of potassium during the course, whereas a decrease was seen in urinary sodium concentration. The fairly good correlations between the decrease in urinary sodium levels and the increase in PRA (r = 0.7) and further between PRA and serum aldosterone (r = 0.8) during the course indicate that there is a causal connection between the decrease in urinary sodium excretion and the increase in PRA and serum aldosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Hormonal response to electrocautery of the ovary in patients with polycystic ovarian disease.

Fifty-eight women with polycystic ovarian syndrome (PCO) were treated with electrocautery of the ovarian capsule and then studied by hormone analysis for 12 months. In 72% ovulation appeared to occur within 4 weeks and in this group mean serum LH and FSH levels showed a statistically significant increase the day after electrocautery, followed by a gradual decline in LH to a level significantly below the pretreatment value. No changes in LH and FSH were seen in those who did not ovulate. The mean levels of testosterone, androstenedione and dihydrotestosterone which were in the upper normal range or slightly above before treatment were significantly reduced after electrocautery. Serum oestradiol levels showed a significant increase after 1 week, when progesterone levels were still unchanged, suggesting that follicular development was already in progress. The mean serum level of sex hormone binding globulin was slightly below the normal range before treatment and then increased gradually. Endocrine responses to electrocautery were similar to those described previously after wedge resection. The simplicity of this treatment and the good response make it an attractive alternative for treating infertility associated with PCO.

Androstenedione↗
PubMed1985

White blood cell populations in patients undergoing major vascular surgery.

In 16 patients undergoing major vascular surgery, study was made of variations in white blood cell populations, cortisol concentration, pulmonary vascular resistance and intrapulmonary shunting. Six hours post-operatively the number of circulating lymphocytes and the relative proportion of T-lymphocytes were significantly reduced. During and after operation the relative proportion of T-suppressor cells rose from 20.5 to 44.8% of all lymphocytes. There was corresponding fall in T-helper cells. The proportion of lymphocytes with surface-bound Ig (B-lymphocytes) did not alter during surgery. No correlation was found between the number of circulating white blood cells and the haemodynamic parameters. Intrapulmonary shunting, which was increased already before operation, remained unchanged during and after surgery. Cortisol levels increased significantly and peaked 6 hours postoperatively. Significant correlations were found between cortisol levels and reduction in total number of lymphocytes and in percentage of T-lymphocytes. The study thus demonstrated significant changes in white blood cell populations following major vascular surgery and indicated a correlation between lymphocyte concentration and cortisol level.

Aged↗
PubMed1984

Spermatogenesis and hormonal status after orchiectomy for cancer and before supplementary treatment.

Low numbers of sperm cells (less than 20 million/ml), low motility indices (less than 40) and/or a high percentage of abnormal sperm cells (greater than 80%) were found in about half of 60 patients with testicular cancer after orchiectomy and before further treatment. There was no correlation between these findings and the patient's age, tumor histology or clinical stage. Relatively low serum testosterone values in the majority of patients and increased serum LH and FSH in some patients also indicated disturbed gonadal function at the time of fertility evaluation. The clinical significance of cryopreservation of sperm cells is therefore questionable in the majority of these patients. The demonstrated hypofertility after orchiectomy and before further treatment for testicular cancer may, however, be reversible at least in some patients. In patients with testicular cancer every attempt should be made to preserve the patients' fertility during the necessary diagnostic and therapeutic procedures, without a reduction in the high cure rate which is obtained by modern multimodal treatment of testicular cancer.

Adolescent↗
PubMed1984

Ovarian production of progesterone and 20 alpha-dihydroprogesterone in vitro following prostaglandin F2 alpha induced luteolysis in the superluteinized rat.

Superluteinized rats were injected with the prostaglandin F2 alpha (PGF2 alpha) analogue cloprostenol to induce luteolysis. The treatment decreased progesterone production of ovarian homogenates from 8.9 +/- 0.5 to 4.0 +/- 0.7 nmol/ovary/10 min (mean +/- SEM) within 40 min. tochondrial fractions isolated from control and cloprostenol treated animals produced 4.7 +/- 0.4 and 2.8 +/- 0.3 nmol progesterone/ovary/10 min, respectively. Thus, the PGF2 alpha analogue treatment significantly reduced mitochondrial progesterone production. Addition of the 15 000 X g supernatant fraction did not influence the progesterone production rates of the mitochondrial fraction. The basal progesterone secretion from quartered ovaries decreased from 1.50 +/- 0.15 to 0.38 +/- 0.05 nmol/ovary during the initial 15 min of incubation following cloprostenol administration. hCG and N6,O2'-dibutyryladenosine 3':5'-cyclic monophosphate (DBC) stimulated the progesterone secretion from quartered ovaries, but the response was delayed in ovaries obtained from cloprostenol treated animals. Although the response was delayed, the progesterone secretion following cloprostenol treatment was re-activated with cAMP either directly or via hCG. The increment in progesterone secretion above unstimulated controls in response to DBC was not influenced by the cloprostenol treatment while the increment caused by hCG was decreased. Our data suggest that: 1) PGF2 alpha deactivates mitochondrial progesterone production, 2) this deactivation may be overcome by cAMP, and 3) PGF2 alpha decreases gonadotrophin responsive adenylyl cyclase.

20-alpha-Dihydroprogesterone↗
PubMed1984

Menstrual dysfunction in Norwegian top athletes.

Of 301 Norwegian female top athletes, all members of the national team in 27 different sports, who were approached with a questionnaire about menstrual function, 278 (92.4%) responded. Ninety-nine of the respondents who used oral contraceptives were excluded. Of the remaining 179, 18 (10.1%) reported secondary amenorrhea (greater than 4 months since the last period) and were chosen for further studies. Blood samples were drawn for hormonal analyses between 10 and 12 a.m. and at least 12 hours after the last training session. Their mean age was 20.8 years (range 18-27), mean height 169.8 cm (160-180), mean weight 58.5 kg (51-67), and their mean age at menarche 14.6 years (13-16.5), significantly older than that of the other top athletes: 13.5 years (p less than 0.05). Their mean number of training hours per week was 16.1 (12-24). Hormonal changes were consistent with simple normoprolactinemic hypothalamic suppression, characterized by low values of FSH, estradiol-17 beta and prolactin. The androgen hormones demonstrated high levels of dihydrotestosterone. Testosterone levels were within normal limits, but in the upper part of the range, whereas sex hormone-binding globulin was in the lower normal range.

Adolescent↗
PubMed1983

The effect of sleep deprivation on the plasma levels of hormones during prolonged physical strain and calorie deficiency.

The effect of sleep on the serum levels of hormones during prolonged heavy physical strain and calorie deficiency were investigated in 19 young men participating in a 5 day ranger training course with a calorie consumption of 35,000-50,000 kJ X 24 h-1, and a calorie intake of about 6,000 kJ X 24 h-1. The subjects were divided into two groups: the stress group (8 cadets) were allowed no organized sleep during the course, whereas the sleep group (9 cadets) had 3 h sleep each night. Small but significantly (p less than 0.01) higher serum levels were found in the sleep group compared to the stress group for cortisol, growth hormone and testosterone. No such differences were found for catecholamines, androstendione, dihydrotestosterone, LH, triiodothyronine and thyroxine. Androstendione and dihydrotestosterone decreased in parallel with testosterone (r = 0.5) during the course, changes which directly or indirectly seem to be due to decreased testicular secretion. The changes found during this investigation for the other hormones are similar to changes found during previous courses. LH showed only small variation during the course and cannot explain the decreased secretion from the testis or the difference between the two groups for testosterone. All hormones were normal within 23 days after the end of the course.

Adrenal Cortex Hormones↗
PubMed1983

Assay of cortisol with a radioimmunoassay method calibrated by isotope dilution-mass spectrometry. A Nordic collaborative study.

A reference method for serum cortisol, based on isotope dilution-mass spectrometry (ID-MS), was compared with a modified commercial RIA method. The modification solely concerned the calibration standards used in the RIA method. These were replaced by a series of human serum samples, in which the concentration of cortisol had been determined by the reference ID-MS method. The samples were selected so as to cover the whole range of the standard curve. Serum samples from healthy, untreated subjects with cortisol concentrations 270-1134 nmol/l were analysed with the ID-MS calibrated RIA method in four laboratories, one in each of the four Nordic countries. The results from two of the four laboratories did not differ significantly from the ID-MS values (P less than 0.05), whereas the results from the other two laboratories differed slightly. The mean values based on results from all four laboratories were almost identical with the values obtained with the reference method. In addition, serum samples from 11 patients with endocrine disorders with cortisol concentrations 31-916 nmol/l were analysed in three of the four laboratories. In three of the samples significant differences were observed between the values obtained with the ID-MS and the ID-MS calibrated RIA method. The value obtained with the ID-MS calibrated RIA was however always more accurate than the corresponding value obtained with RIA with the use of a commercial calibration standard. Advantages of the present model in increasing the accuracy of routine analysis by RIA are discussed. The possibility is further discussed that the ID-MS calibrated RIA method may be used as a 'secondary reference method'.

Adult↗
PubMed1982

Decreased serum levels of oestradiol, testosterone and prolactin during prolonged physical strain and sleep deprivation, and the influence of a high calorie diet.

The changes in oestradiol, testosterone and prolactin, and the effects of a high calorie diet, were investigated in eleven young males cadets participating in a 5 days' ranger training course involving heavy and continuous physical activities with less than 1500 kcal . day-1 and almost without sleep. Prolactin decreased continuously during the first 24 h to 25% of precourse values. Testosterone decreased during the day time and reached below 25% of precourse values after 48 h. Oestradiol did not change during the first 48 h but then decreased to about 50% of precourse values. In conclusion, oestradiol, testosterone and prolactin are strongly reduced during prolonged strain. These changes were not reversed by a high calorie diet.

Adult↗