SUMMARY1. Six well-trained cyclists and six untrained subjects were studied during and immediately after four successive 7 min periods of exercise at 30, 45, 60 and 75 % of their maximal work capacity.2. Venous blood samples were taken at rest, at the end of each exercise period and 5 min following the end ofexercise, for estimation of metabolites in blood and plasma insulin, growth hormone, cortisol and catecholamines.3. The results showed significant differences in the mobilization and utilization of muscle fuels between the athletically fit cyclists and the untrained group. In the cyclists, glucose, glycerol and free fatty acid concentrations were higher, but lactate, pyruvate and alanine were lower than in the untrained subjects during exercise.4. Plasma catecholamines rose in both groups during exercise but the rise was significantly less in the racing cyclists. Plasma insulin was depressed to a greater extent in the untrained subjects during exercise and plasma glucagon rose to a greater extent during strenuous exercise and remained elevated after the end of exercise in the untrained group. Plasma human growth hormone rose to a greater extent during exercise and remained elevated after the end of exercise in the untrained group. Plasma cortisol fell at low and moderate exercise rates in both groups, but to a smaller extent in the cyclists. Cortisol values rose at higher workloads and were significantly higher in the cyclists at the end of exercise.5. It is concluded that there are significant differences in the metabolic and hormonal responses to exercise between athletically trained and untrained individuals, even when the physically fit subjects work at the same percentage of their maximal capacity as the unfit subjects.

Letrozole and anastrozole are potent aromatase inhibitors (AI) that peripherally decrease the production of estrogens from androgens w1x. They are highly selective, orally administered, and easy to monitor w2x. This study was carried out to compare their effect on producing ovulation and conception in infertile, clomiphene-resistant women with polycystic ovary syndrome (PCOS).Forty non-fertile women with PCOS were enrolled in this study. Tubal, peritoneal, and uterine causes of infertility were excluded by laparoscopic hysterosalpingogram or by ultrasonography. Specific endocrine abnormalities and causes of infertility due to the husbands were also excluded. Patients had to end clomiphene treatment at least 2 months before enrolment. Serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol (E ) were 2 assessed and ultrasound examinations were performed on day 1 or 2 of the menstrual cycle, and then from day 9 on alternating days, ending with administration of human chorionic gonadotropin (hCG). Endometrial thickness and pulsatility index

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The effect of intravenous somatostatin on blood levels of metabolites and hormones has been examined in normal subjects who performed a 30-minute period of bicycle exercises at 70% maximal exercise capacity. The results have been compared with control studies in the same subjects. Measurements were made of blood levels of lactate, glucose, free fatty acids, glycerol, acetoacetate, 3-hydroxybutyrate, insulin, glucagon, growth hormone (hGH) and prolactin. Growth hormone and glucagon release were suppressed during exercise with somatostatin and there was a subsequent elevation during recovery. There was slight post-exercise depression of insulin, but no alteration of plasma prolactin secretion. Blood glucose was reduced during exercise with somatostatin and increased during recovery. The elevation of ketone bodies after exercise was greater in the investigation with somatostatin, but there were no significant changes in other metabolites. Somatostatin, although causing inhibition of hGH release, appeared to have no significant effect upon fatty acid mobilization during exercise.