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Biomedical subjects

A Pakarinen

Publications and source records attributed to A Pakarinen.

At least 37 records · Page 2Linked to original sources
PubMed1989

Abrupt change from a beta-adrenoceptor blocking drug to enalapril in hypertension.

The haemodynamic and hormonal effects of an elective change of antihypertensive therapy from a beta-adrenoceptor blocking drug to a converting enzyme inhibitor, enalapril, were monitored in 12 hypertensive in-patients (WHO I). Blood pressure and heart rate were determined every 2-4 h using an automatic sphygmomanometer during an abrupt cessation of the previous beta-adrenoceptor blocking drug and commencement of treatment with enalapril 20 mg o.d. 12 h later. Mean blood pressure values at rest and during the hand grip test were lower when on enalapril, but heart rate was significantly higher, and three patients suffered from palpitations during the change. The change resulted in an improvement in cardiac function both at rest and during isometric work, as shown by echocardiography. A rapid decrease in plasma angiotensin converting enzyme (ACE) activity and an increase in renin activity were also seen after the change, while plasma levels of atrial natriuretic peptide (ANP) decreased towards normal values. The results suggest that an abrupt change from a chronic beta-adrenoceptor blocking drug to enalapril is safe, feasible and is likely to produce favourable haemodynamic and hormonal effects in hypertensive patients.

Adrenergic beta-Antagonists↗
PubMed1988

Serum thyroid hormones, thyrotropin and thyroxine binding globulin during prolonged strength training.

The effects of progressive strength training for 24 weeks on maximal strength and pituitary-thyroid function were studied in 21 males during the training and during the following detraining period of 12 weeks. Maximal strength increased greatly (p less than 0.001) in the first 20 weeks, followed by a plateau phase in the last 4 weeks of training. Maximal strength decreased greatly (p less than 0.001) during the detraining period. The concentrations of serum total (T4) and free thyroxine (fT4) decreased (p less than 0.05 and less than 0.01, respectively) during the training period and they rose to pretraining levels during the detraining period. During the most intense training phase (the last 4 weeks) there was a positive correlation between the changes in serum fT4 concentrations and the changes in maximal force (r = 0.56; p less than 0.01). No statistically significant changes occurred in the levels of serum triiodothyronine, thyrotropin or thyroxine binding globulin. The results show that prolonged intensified strength training can slightly decrease the concentrations of serum total and free T4. These small changes cannot have any clinical significance, and even their physiological significance may be only marginal.

Adult↗
PubMed1988

Neuromuscular and hormonal responses in elite athletes to two successive strength training sessions in one day.

Acute neuromuscular and endocrine adaptations to weight-lifting were investigated during two successive high intensity training sessions in the same day. Both the morning (I) (from 9.00 to 11.00 hours) and the afternoon (II) (from 15.00 hours to 17.00 hours) training sessions resulted in decreases in maximal isometric strength (p less than 0.01 and less than 0.05), shifts (worsening) in the force-time curve in the absolute scale (p less than 0.05 and ns.) and in decreases in the maximal integrated EMG (p less than 0.01 and less than 0.05) of the selected leg extensor muscles. Increases in serum total (p less than 0.05) and free testosterone (p less than 0.01) and in cortisol (p less than 0.01) concentrations were found during training session II. These were followed by decreases (p less than 0.001 and p less than 0.01 and ns.) in the levels of these hormones one hour after the termination of the session. The responses during the morning training session were different with regard to the decreases in serum total testosterone (p less than 0.05), free testosterone (ns.) and cortisol (p less than 0.05). Only slight changes were observed in the levels of luteinizing hormone and sex hormone-binding globulin during the training sessions. Increases (p less than 0.01) took place in somatotropin during both training sessions. The present findings suggest that high intensity strengthening exercises may result in acute adaptive responses in both the neuromuscular and endocrine systems. The diurnal variations may, however, partly mask the exercise-induced acute endocrinological adaptations in the morning.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Responses of serum androgenic-anabolic and catabolic hormones to prolonged strength training.

Endocrine and neuromuscular effects of prolonged strength training were investigated in 21 strength-trained male subjects during the course of a 24-week progressive strength training and during a subsequent detraining period of 12 weeks. Maximal isometric leg extensor force increased by 19% (P less than 0.001) during the first 20 weeks, followed by a plateau during the 4 latest weeks of training. During the course of the training period, no systematic change was found in serum testosterone concentrations, but there was a decreasing tendency in the concentrations of free testosterone (NS), 17-OH-progesterone (NS), androstenedione (P less than 0.05), dehydroepiandrosterone (P less than 0.05), cortisol (P less than 0.01), transcortin (CBG) (P less than 0.05), and in the cortisol/CBG ratio (P less than 0.05). The last 4 weeks of training were characterized by significant correlations between the individual changes in maximal isometric force and the changes in serum free testosterone concentrations (r = 0.60, P less than 0.01). The changes in the ratios of free testosterone to cortisol (r = 0.73, P less than 0.001), total testosterone to cortisol (r = 0.83, P less than 0.001), and 17-OH-progresterone to cortisol (r = 0.62, P less than 0.01) also correlated with the changes in maximal force. The findings suggest that the turnover of endogenous androgens may increase during progressively intensified training without a change in serum total testosterone concentration. Prolonged intensive strength training may also lead to changes in the concentrations of serum cortisol and transcortin. During the most stressful phases of training, the changes in serum androgen/cortisol ratios seem to be highly individual and may correlate with changes in muscular strength.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Daily hormonal and neuromuscular responses to intensive strength training in 1 week.

Daily adaptive responses in the neuromuscular and endocrine systems to a 1-week very intensive strength training period with two training sessions per day were investigated in eight elite weight lifters. The morning and the afternoon sessions resulted in acute decreases (P less than 0.05-0.01) in maximal isometric strength and in the maximal neural activation (iEMG) of the leg extensor muscles, but the basic levels remained unaltered during the entire training period. Significant (P less than 0.05-0.01) acute increases in serum total and free testosterone levels were found during the afternoon sessions. During the 1-week training period, serum total and free testosterone concentrations decreased gradually (P less than 0.05-0.001) as observed in the basic morning values before the sessions, but after 1 day of rest serum total and free testosterone reached (P less than 0.01 and 0.05) the pretraining level. The sessions resulted also in acute changes (P less than 0.05-0.01) in serum cortisol and somatotropin concentrations, but the basic morning levels did not change during the training period. The present findings suggest that during a short period of intense strength training the changes especially in serum testosterone concentrations indicate the magnitude of physiologic stress of training. The acute changes in serum hormone concentrations during a period of a few days do not, however, necessarily directly imply the changes in performance capacity. A longer period of follow-up lasting a few weeks is probably needed if an individual trainability status of a strength athlete is to be evaluated on the basis of the hormone determinations.

Adult↗
PubMed1988

Neuromuscular and hormonal adaptations in athletes to strength training in two years.

Neuromuscular and hormonal adaptations to prolonged strength training were investigated in nine elite weight lifters. The average increases occurred over the 2-yr follow-up period in the maximal neural activation (integrated electromyogram, IEMG; 4.2%, P = NS), maximal isometric leg-extension force (4.9%, P = NS), averaged concentric power index (4.1%, P = NS), total weight-lifting result (2.8%, P less than 0.05), and total mean fiber area (5.9%, P = NS) of the vastus lateralis muscle, respectively. The training period resulted in increases in the concentrations of serum testosterone from 19.8 +/- 5.3 to 25.1 +/- 5.2 nmol/l (P less than 0.05), luteinizing hormone (LH) from 8.6 +/- 0.8 to 9.1 +/- 0.8 U/l (P less than 0.05), follicle-stimulating hormone (FSH) from 4.2 +/- 2.0 to 5.3 +/- 2.3 U/l (P less than 0.01), and testosterone-to-serum sex hormone-binding globulin (SHBG) ratio (P less than 0.05). The annual mean value of the second follow-up year for the serum testosterone-to-SHBG ratio correlated significantly (r = 0.84, P less than 0.01) with the individual changes during the 2nd yr in the averaged concentric power. The present results suggest that prolonged intensive strength training in elite athletes may influence the pituitary and possibly hypothalamic levels, leading to increased serum levels of testosterone. This may create more optimal conditions to utilize more intensive training leading to increased strength development.

Adaptation, Physiological↗
PubMed1987

Relationships between training volume, physical performance capacity, and serum hormone concentrations during prolonged training in elite weight lifters.

A follow-up study of 1 year was performed on 11 male elite weight lifters. Several parameters including training volume, weight lifting performance, and serum hormone concentrations were measured during seven test occasions. In addition, the same measurements were repeated three times during a 6-week period preceding the primary competition, which took place about 5 months after beginning of the follow-up. The primary findings were observed during the 6-week period from which the first 2 weeks of stressful training was associated with significant decreases (P less than 0.01-0.001) in serum testosterone concentration, in testosterone/cortisol and in testosterone/SHBG ratios, and with a significant (P less than 0.001) increase in serum LH concentration. The individual changes during the stressful training in serum testosterone/SHBG ratio were related (r = .63; P less than 0.05) to the individual changes in the weight lifting result in the clean and jerk lift. During the following "normal" 2-week and reduced 2-week training periods, the concentration of serum testosterone remained unaltered, but serum cortisol and serum LH decreased significantly (P less than 0.05-0.01). During these periods, the serum testosterone/SHBG ratio increased (P less than 0.01). The individual changes during this preparatory 4-week training before the primary competition in serum testosterone/SHBG ratio and the individual changes in the weight lifting result in the clean and jerk lift correlated significantly with each other (r = .68; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Decreased renal perfusion after correction of experimental coarctation.

Hemodynamical changes in coarctation were studied with an experimental model. Coarctation of the thoracic aorta was induced in seven puppies at the age of 8 wk. After a 7-month follow-up period a corrective operation with a venous patch was performed. Two dogs were lost a few hours after the correction operation. The remaining five dogs were followed for 12 months postoperatively. Renal perfusion was measured with a 133Xenon washout method just prior to the operation, 1 h, 6 and 12 months postoperatively. The glomerular filtration rate was measured using the 51Cr-EDTA method 1 wk before the operation, 3 wk, 2, 6, and 12 months after it. Six healthy adult dogs were used as controls for glomerular filtration rate measurements. Peripheral renin activity was measured at operation, just before the correction of aortic coarctation, 1/2, 1 h, 1, 3, 7 days, 2 and 6 months after the correction operation. Renal perfusion decreased significantly (p less than 0.05) immediately after the correction operation and rose again during the follow-up. Peripheral renin activity rose significantly (p less than 0.01) from the preoperative values and was at its greatest 1 day after the operation. Later on, peripheral renin activity values returned to normal. Coarctated dogs had significantly (p less than 0.01) lower glomerular filtration rate values than controls in each measurement except at the 2 months postoperative measurement. These results support decreased renal perfusion with resultant increased peripheral renin activity as part of the pathomechanism of the paradoxical hypertension observed after correction of coarctation.

Animals↗
PubMed1987

Inverse seasonal relationship between melatonin and ovarian activity in humans in a region with a strong seasonal contrast in luminosity.

The effects of season on the activity of the pituitary-ovarian axis and the pineal gland were studied in 11 women by serum and urinary melatonin determinations and in 21 women by measurements of the serum concentrations of anterior pituitary and ovarian hormones during the dark and light seasons. A melatonin index was determined by integration of the area below the curve of serum melatonin concentrations during 24-h periods in both seasons. During the dark season, the daytime 12-h melatonin index and daytime urinary melatonin excretion were significantly higher than during the light season. In addition, the duration of the nocturnal melatonin pulse (serum melatonin levels, greater than 65 pmol/L) was lengthened during this season, whereas the mean serum estradiol concentration was significantly decreased at the time of ovulation and during the luteal phase of the cycle, indicating lowered ovarian activity. Luteal phase gonadotropin concentrations were increased during the dark season, which was also characterized by increased sex hormone-binding globulin (SHBG) and decreased free testosterone concentrations and free androgen indices (ratio of testosterone to SHBG X 700) throughout the menstrual cycle. The dark season was thus characterized by increased melatonin secretion and decreased ovarian and androgenic activities. In summary, we characterized two season-dependent hormonal phenomena. Although we did not prove any cause and effect association between melatonin and anterior pituitary-ovarian hormones, the inverse seasonal relationship in pineal gland and ovarian secretion suggests that melatonin is causally related to reproduction in humans.

Adult↗
PubMed1987

Serum concentrations of thyrotropin, thyroxine, triiodothyronine and thyroxine binding globulin in female endurance runners and joggers.

The effects of endurance training and season on the function of the anterior pituitary-thyroid axis were studied in 18 female runners and their 12 controls, and in 13 joggers and their 11 controls in Northern Finland, with a large seasonal difference in environmental factors. The serum concentrations of thyrotropin (TSH), thyroxine (T4), free thyroxine (fT4), triiodothyronine (T3), thyroxine binding globulin (TBG) and oestradiol (E2) were measured during one menstrual cycle in the light training season (autumn) and in the hard training season (spring). The responses of TSH to intravenous TRH stimulation were also measured in the luteal phase of the cycle during the hard training season. Endurance running did not affect the basal or TRH-stimulated serum TSH concentrations, while those of T4 and fT4 in runners were lowered in both seasons and that of T3 in the light training season in relation to control subjects. The serum concentrations of TBG were also significantly lower in runners than their controls in the luteal phase in both seasons. The effect of jogging on thyroid hormones was less pronounced. Serum concentrations of TSH, T4, fT4, T3 and TBG were generally slightly higher in spring than in autumn. Strenuous endurance training seems to have minor changes on the function of the thyroid gland. Depressed T4 levels in runners may rather be due to lowered TBG levels than due to direct effect of training. In spring the function of anterior pituitary-thyroid axis is more active than in autumn.

Adult↗
PubMed1987

The effect of season on the circulating concentrations of anterior pituitary, ovarian and adrenal cortex hormones and hormone binding proteins in the subarctic area; evidence of increased activity of the pituitary-ovarian axis in spring.

To evaluate the effects of season on the function of the pituitary-ovarian axis and the adrenal cortex in a northern area with great seasonal variation in the length of daylight, 10 healthy women were investigated over 1 menstrual cycle in spring (May-June), autumn (August-September), early winter (November-December) and late winter (February-March). Serum concentrations of LH, FSH, prolactin, estradiol, progesterone, total and free testosterone, cortisol, sex hormone binding globulin (SHBG) and cortisol binding globulin (CBG) were measured, and the indices of free estradiol (FEI), free androgen (FAI) and free cortisol (FCI) were calculated on cycle days 3-4, 6-7, 10-11, on the presumed day of ovulation, and 6-7 and 9-10 days after the presumed ovulation. Spring was the season that most significantly differed from the other seasons. It was characterized by a significantly decreased concentration of SHBG and an increased FAI throughout the whole menstrual cycle, an increased FSH concentration during the follicular phase, significantly increased estradiol concentration and an increased FEI, and significantly decreased concentrations of FSH and LH during the luteal phase of the cycle. The concentration of cortisol and the FCI were significantly increased in the autumn compared with late winter, both seasons having similar day-length. The present data demonstrate that spring, with a long photoperiod, seems to be associated with increased pituitary-ovarian axis activity and androgenic activity, whereas adrenal cortex function did not show any association with day-length.

Adrenal Cortex Hormones↗
PubMed1985

Serum hormones during prolonged training of neuromuscular performance.

The effects of a 24-weeks' progressive training of neuromuscular performance capacity on maximal strength and on hormone balance were investigated periodically in 21 male subjects during the course of the training and during a subsequent detraining period of 12 weeks. Great increases in maximal strength were noted during the first 20 weeks, followed by a plateau phase during the last 4 weeks of training. Testosterone/cortisol ratio increased during training. During the last 4 weeks of training changes in maximal strength correlated with the changes in testosterone/cortisol (P less than 0.01) and testosterone/SHBG (P less than 0.05) ratios. During detraining, correlative decreases were found between maximal strength and testosterone/cortisol ratio (P less than 0.05) as well as between the maximal strength and testosterone/SHBG ratio (P less than 0.05). No statistically significant changes were observed in the levels of serum estradiol, lutropin (LH), follitropin (FSH), prolactin, and somatotropin. The results suggest the importance of the balance between androgenic-anabolic activity and catabolizing effects of glucocorticoids during the course of vigorous strength training.

Adult↗
PubMed1985

Renal structure and function in chronic experimental aortic coarctation in dogs treated with antihypertensive drugs.

The possible damaging effect on the kidneys of antihypertensive therapy in aortic coarctation was evaluated experimentally in eighteen canine puppies. Aortic coarctation was carried out in 13 puppies at the age of two months while sham-surgery was carried out on five control puppies. Six coarctated dogs were treated with hydrochlorothiazide, propranolol and prazosin. Antihypertensive therapy was started two months after the operation. Seven coarcted puppies did not receive any treatment. The dogs were followed up for 7 months after which fixation of the kidneys was performed. Antihypertensive therapy decreased blood pressure significantly although the level seen in the control dogs was not attained. There were no signs of deterioration of renal function. Neither light microscopic analysis nor electron microscopy revealed morphological abnormalities in the kidneys of any of the dogs. The present results show that active antihypertensive therapy in experimental coarctation, although not resulting in a normalization but in a significant lowering of blood pressure, is safe and does not cause any morphologic damage in the kidney before corrective surgery. The absence of juxtaglomerular hypertrophy supports the hypothesis that the renin-angiotensin system is not activated in chronic coarctation of aorta.

Animals↗
PubMed1985

Physical exercise-induced changes and season-associated differences in the pituitary-ovarian function of runners and joggers.

The hormonal responses to energetic chronic exercise and to seasonal shift from autumn to spring were evaluated by measuring concentrations of serum FSH, LH, PRL, estradiol (E2), progesterone (P), testosterone (T), and sex hormone-binding globuline (SHBG) during 1 menstrual cycle in the autumn (light training season) and 1 in the spring (hard training season) in 18 endurance runners and 12 age-matched nonrunning women, and in 13 joggers and 11 age-matched nonjogging women. The appearance, growth, and maximal size of the ovarian follicles were monitored by ultrasonography. The high intensity training of the runners was associated with decreased concentrations of FSH on cycle days 7-8 in the autumn, E2 on cycle days 12-13 in the spring and days 22-23 in both seasons, P on cycle days 20-21 in both seasons and days 22-23 in the autumn, and T on cycle days 12-13, 14-15, and 22-23 in the spring. Jogging, however, did not alter the concentrations of these hormones. Using as criteria the presence of 2 or 3 abnormal values of the 3 indicators used for evaluation of folliculogenesis (midfollicular E2 lower than 0.09 nmol/liter, luteal phase P lower than 7 nmol/liter, and peak diameter of the largest ovarian follicle less than 15 mm), seriously disturbed folliculogenesis was found in 50% of the 32 study cycles of the runners and 9% of the 23 cycles of their controls (P less than 0.01). In all four study groups, there was a significant seasonal difference in the concentrations of ovarian hormones, with lowered E2, P, and T levels in the autumn. There were no differences in the serum concentrations of SHBG between the study groups or between the autumn and the spring. High training activity and a dark photoperiod appeared to independently suppress ovarian activity and were not associated with chronic changes in anterior pituitary hormone or SHBG concentrations.

Adolescent↗
PubMed1984

Pubertal and menstrual disorders of female runners, skiers and volleyball players.

In order to evaluate the onset of puberty and the presence of menstrual disorders in Finnish sportswomen with different training programs, 53 long-distance runners, 39 skiers and their 93 controls, and 63 volleyball players with 64 controls were interviewed. All the sportswomen had trained intensively for several years and were in the top category of their sport in Finland. Menarche and thelarche in all the sportswomen and also pubarche in the volleyball players developed significantly later than in their controls. The runners and skiers (43%) suffered significantly more often from menstrual irregularities than their controls (27%), whereas volleyball players (19%) did not differ from their controls (13%) in this respect. Among runners and skiers, but not among volleyball players, premenarchal start of sports activity had an aggravating effect on these endocrine disorders. Dysmenorrhea was found to occur more seldom in sportswomen than in the control subjects, and physical exercise often alleviated menstrual distress. Because the runners and skiers trained as often and used as much time for their sport as the volleyball players, the more common occurrence of their menstrual disorders may be due to the nature of training and competition activity which is characterized by endurance physical exercise.

Adolescent↗