Neoklis A. Georgopoulos

The influence of intensive physical training on growth and pubertal development in athletes

Genetic potential for growth can be fully expressed only under favorable environmental conditions. Although moderate physical activity has beneficial effects on growth, excessive physical training may negatively affect it. Sports favoring restricted energy availability, in the presence of high energy expenditure, are of particular concern. In gymnastics, a different pattern in skeletal maturation and linear growth was observed, resulting in an attenuation of growth potential in artistic gymnasts (AG), more pronounced in males than in females. In female rhythmic gymnasts (RG), the genetic predisposition to growth was preserved owing to a late catchup growth phenomenon. In all other sports not requiring strict dietary restrictions, no deterioration of growth has been documented so far. Intensive physical training and negative energy balance alter the hypothalamic pituitary set point at puberty, prolong the prepubertal stage, and delay pubertal development and menarche in a variety of sports. In elite RG and AG, prepubertal stage is prolonged and pubertal development is entirely shifted to a later age, following the bone maturation rather than the chronological age.

Measurement of salivary resistin, visfatin and adiponectin levels

Hormonal determination in saliva offers several advantages. Peptides enter the salivary glands either by active transport mechanisms or are expressed and secreted by the salivary glands themselves. The collection of saliva is a noninvasive, easily repeatable and less stressful technique than blood withdrawal. The purpose of the present study was to introduce a method for measuring salivary resistin, visfatin and adiponectin levels and to evaluate their associations with serum levels. Resistin, visfatin and adiponectin levels were measured in serum and saliva of 50 healthy adult volunteers (17 male and 33 female) using commercial enzyme immunoassay kits for serum with minor modifications. The present study documented the determination of resistin and adiponectin levels in saliva and the significant correlation of salivary levels with serum levels (r=0.441, p<0.01 and r=0.347, p<0.05, respectively). Moreover, the identification of visfatin in saliva was achieved, but no significant correlation with serum visfatin levels was observed. To our knowledge, this is the first study to report the determination of resistin and visfatin in saliva and the significant correlation of salivary resistin with serum levels, while it confirmed the significant association between salivary and serum adiponectin. The introduction of salivary determinations of adipokines could contribute to the elucidation of the physiology and the role of the specific adipokines in various clinical conditions (obesity, insulin resistance, inflammation, reproduction, energy imbalance and stress response).

Basal metabolic rate is decreased in women with polycystic ovary syndrome and biochemical hyperandrogenemia and is associated with insulin resistance.

OBJECTIVE To evaluate basal metabolic rate (BMR) in women with PCOS and to determine its association with insulin resistance (IR). DESIGN Prospective assessment of BMR in women with PCOS. SETTING Outpatient clinic of the Division of Reproductive Endocrinology. PATIENT(S) The study included 91 Greek women with PCOS and biochemical hyperandrogenemia, with mean age 24.03 +/- 0.55 years and mean body mass index (BMI) 26.67 +/- 0.69 kg/m(2), and 48 matched regularly menstruating women, with mean age 26.33 +/- 0.93 years and mean BMI 23.35 +/- 0.85 kg/m(2), as control subjects. INTERVENTION(S) Assessment of BMR by indirect calorimetry, IR by HOMA and QUICKI indices, fasting insulin, and fasting glucose/insulin ratio. MAIN OUTCOME MEASURE(S) Reduced BMR in PCOS with or without IR. RESULT(S) Adjusted BMR was 1,868 +/- 41 kcal/day in the control group, 1,445.57 +/- 76 in all PCOS women, 1,590 +/- 130 in PCOS women without IR and 1,116 +/- 106 in PCOS women with IR. Adjusted BMR showed a statistically significant difference between women with PCOS and control subjects, with lowest values in the group of PCOS women with IR, even after adjusting all groups for age and BMI. CONCLUSION(S) Women with PCOS, particularly those with IR, present a significantly decreased BMR.

Growth hormone, insulin-like growth factor-I axis, and insulin secretion in hyperandrogenic adolescents * †

OBJECTIVE To assess GH and insulin-like growth factor I (IGF-I) axis variability in hyperandrogenic adolescents with different sources of androgen excess and their relationship with insulin resistance. DESIGN Baseline IGF-I, insulin-like growth factor binding protein-1 (IGFBP-1), IGFBP-3, GH response to the exercise-propranolol test, and insulin responses to a standard oral glucose tolerance test were compared among patients with functional ovarian hyperandrogenism, hyperandrogenic nonfunctional ovarian hyperandrogenism patients, and age-matched controls. SETTING Outpatient clinic in a medical center. PATIENTS Twenty-one adolescents with ovarian (group A) and 17 with nonovarian (group B) hyperandrogenism, and 20 controls. RESULTS Serum IGF-I and poststimulated GH levels were similar among groups, whereas serum IGFBP-3 levels were significantly lower in group A than in controls. Mean serum insulin levels were significantly higher in patients than in controls, whereas 24% of patients had abnormal insulin responses to glucose and/or insulin sensitivity indexes. Serum IGFBP-3 levels correlated negatively with the free androgen index (free androgen index = T/sex hormone-binding globulin [SHBG] x 100), whereas mean serum insulin levels correlated positively with the free androgen index and negatively with SHBG levels in all subjects. CONCLUSIONS Hyperinsulinemia is common in hyperandrogenic adolescents and correlates with the degree of hyperandrogenism and not with the androgen source. Hyperinsulinemia and decreased IGFBP-3 levels may enhance IGF-I bioavailability, which in turn may both decrease SHBG levels and increase androgen production.

The impact of oral contraceptives and metformin on anti-Müllerian hormone serum levels in women with polycystic ovary syndrome and biochemical hyperandrogenemia

Objective. To assess the impact of metformin and of two different oral contraceptives (OCs) containing cyproterone acetate and drospirenone, on serum anti-Müllerian hormone (AMH) levels, in a cohort of women with polycystic ovary syndrome (PCOS) with hyperandrogenism. Design. Prospective randomised study. Setting. Division of Endocrinology and Human Reproduction, Aristotle University of Thessaloniki. Patients. Forty-five (45) women with PCOS diagnosed according to the criteria proposed in 1990 by the NIH. Interventions. Women with PCOS were randomised into three groups, all treated for 6 months: Group A received an OC containing 35 μg ethinylestradiol plus 2 mg cyproterone acetate, Group B received an OC containing 30 μg ethinylestradiol plus 3 mg drospirenone and Group C received metformin 850 mg × 2. Main outcome measure(s). Anti-Müllerian hormone levels were measured by a specific ELISA. Results. AMH was significantly decreased under treatment with 35 μg ethinylestradiol plus 2 mg cyproterone acetate (p = 0.002 at 3 months and p < 0.001 at 6 months). Treatment with 30 μg ethinylestradiol plus 3 mg drospirenone, and treatment with metformin 850 mg × 2 did not significantly affect serum AMH levels. AMH was significantly decreased under OCs treatment compared to metformin 850 mg × 2 (p = 0.005). Conclusion(s). AMH serum levels were significantly decreased under treatment with 35 μg ethinylestradiol plus 2 mg cyproterone acetate, due to decrease in androgens and suppression of gonadotropins.

Functional significance of the thyrotropin receptor germline polymorphism D727E.

In a toxic thyroid adenoma we identified a novel somatic mutation that constitutively activates the thyrotropin receptor (TSHR). Two heterozygous point mutations at adjacent nucleotides led to a substitution of alanine with asparagine at codon 593 (A593N) in the fifth transmembrane helix of TSHR. This somatic mutation resided on the same TSHR allele with the germline polymorphism D727E. The functional characteristics of the single TSHR mutants A593N and D727E and of the double mutant A593N/D727E were studied in transiently transfected COS-7 cells. The TSHR mutants A593N and A593N/D727E constitutively activated the cAMP cascade, whereas the D727E mutant did not differ from the wild-type TSHR. Surprisingly, the double mutants specific constitutive activity was 2.3-fold lower than the A593N mutant. Thus, the polymorphism significantly ameliorates G(alphas) protein activation in the presence of the gain-of-function mutation A593N, although it is functionally inert in the context of the wild-type TSHR.

Novel application of IGF‐I and IGFBP‐3 generation tests in the diagnosis of growth hormone axis disturbances in children with β‐thalassaemia

Children with β‐thalassaemia major (β‐thal) frequently have growth retardation in the presence of low serum IGF‐I and a normal GH response to pharmacological stimulation suggesting that they have GH insensitivity (GHIS). This study was carried out to study the cause of their growth retardation.

The growth pattern and final height of girls with Turner syndrome with and without human growth hormone treatment

Background. Shortness is the most frequent and quite disturbing characteristic of girls with Turner syndrome (TS). Human growth hormone administration (hGH) to girls with TS increases growth velocity (GV), but a favorable effect on final height (FH) has not been documented. The aim of this study was to evaluate the effect of hGH administration on the growth pattern and FH in girls with TS. Methods. The study group was comprised of 123 girls with TS who were cared for in our center. Eighty-two of these girls received hGH (mean dose, 0.78 ± 0.12 IU/kg/week), given subcutaneously 5 to 7 times per week for a period of 2.2 ± 1.2 years (hGH group). The mean chronological age (CA) and bone age (BA) at hGH initiation were 11.5 ± 2.5 years and 9.7 ± 2.3 years, respectively. The remaining 41 girls did not receive hGH and are designated as the untreated control group. In both groups, gonadal steroids were given for pubertal initiation and maintenance. Results. The GV during the first year of hGH therapy (GV1) was higher than the year before hGH (6.3 cm/year vs 4.0 cm/year) and higher than the GV of the untreated group at a similar CA (4.4 cm/year). The GVs during the second (GV2) and third (GV3) year of hGH treatment (5.4 and 4.9 cm/year, respectively) were lower, but still higher in the hGH group, in comparison with the untreated group (GV2, 4.2 cm/year; GV3, 3.4 cm/year). GV1, GV2, and GV3 were negatively related to age and to BA at hGH initiation. The FH of the 35 hGH-treated girls was not significantly different from the FH of the 27 untreated girls (146.1 cm vs 144.0 cm). The Δ target height-FH was not significantly different in the two groups. The FH standard deviation score of the hGH-treated group was positively related to height standard deviation score for CA at treatment initiation (r = +0.73), maternal height (r = +0.57), target height (r = + 0.66), and birth weight (r = +0.54), but was unrelated to CA or BA at start of therapy or to hGH dose. Conclusions. hGH therapy in girls with TS, in the dose and duration of treatment applied in this study, significantly accelerated GV but did not significantly improve FH.

Abolished circadian rhythm of salivary cortisol in elite artistic gymnasts

OBJECTIVE The aim of this study was to evaluate the effects of intensive physical exercise and acute psychological stress during high level athletic competition as reflected on the levels of salivary cortisol in elite artistic gymnasts (AGs). DESIGN The study included 239 AGs (142 females-97 males) who participated in the European Championship of Gymnastics in 2006 and 81 adolescents (40 females-41 males), matched for age, as controls. All athletes participated voluntarily in all or parts of the study, providing samples or data for each of the variables measured. Height, weight, body fat, lean body mass (LBM), bone age and Tanner stage of puberty were assessed and data concerning the time of thelarche, adrenarche and menarche as well as, the onset and the intensity (hours per week) of training were obtained. METHODS Saliva samples were collected, the morning before training and in the afternoon shortly after the competition. From controls, the saliva samples were collected in the morning. Cortisol concentrations were measured using a chemiluminescence method. Acute stress was assessed using a questionnaire designed for the study. RESULTS No difference was found between morning and afternoon salivary cortisol levels in both male and female AGs (females: AM: 15.45±7.45nmol/l vs PM: 15.73±9.38nmol/l; males: AM: 10.21±5.52nmol/l vs PM: 9.93±13.8nmol/l, p>0.05). Female AGs presented higher levels of morning salivary cortisol than female controls (p<0.05). Both male and female AGs had higher degree of psychological stress in comparison with controls (p<0.001, p<0.013, respectively). Female AGs had higher morning and afternoon salivary cortisol levels (p<0.01, p<0.01, respectively) and higher degree of stress (p<0.003) than males. CONCLUSIONS In elite AGs the diurnal rhythm of salivary cortisol has been abolished, probably due to the strenuous training and competition conditions. Female AGs presented higher levels of morning salivary cortisol and psychological stress compared to both male AGs and female controls. The long term consequences of these modifications of the HPA axis remain to be elucidated.

Adequacy of saliva 17-hydroxyprogesterone determination using various collection methods

Steroids determination in saliva offers several advantages. The collection of saliva is a noninvasive, less stressful technique than blood withdrawal and reflects the circulating unbound fractions. The suitability of saliva for 17-hydroxyprogesterone and cortisol determinations has been documented in healthy subjects as well as in diseases like Congenital Adrenal Hyperplasia and Cushing syndrome. The aim of the study was to compare the influence of different collection methods on the results of 17-hydroxyprogesterone measurement in saliva collected by different ways, using commercially available RIAs developed for plasma. 17-hydroxyprogesterone was determined in 64 healthy adult volunteers (30 males, 34 females) in serum (Group SE) and in saliva collected before meals at 8-10 p.m. by directly spitting into a plastic tube (Group SP), using a cotton swab (Group SA) and using a polyester swab Salivette (Group SB). We used a commercially available direct radioimmunoassay without separation technique. The 17-hydroxyprogesterone mean values (ng/ml) were 1.16+/-1.3 (Group SE), 0.056+/-0.046 (Group SP), 0.089+/-0.048 (Group SA) and 0.058+/-0.049 (Group SB). The detection limit was 0.010 ng/ml. The correlations between the values in serum (Group SE) and in saliva were: r=0.77, p<0.05 (Group SP); r=0.62, p<0.05 (Group SA); r=0.70, p<0.05 (Group SB). The saliva values corresponding to the serum cut-off point of 3 ng/ml upper limit of normal values were in ng/ml 0.13 (Group SP), 0.16 (Group SA) and 0.11 (Group SB). In conclusion, 17-hydroxyprogesterone determinations in saliva using commercially available RIAs primarily developed for serum, is a reliable and easy to perform procedure. The three different methods of saliva collection showed 17-hydroxyprogesterone concentrations to have good agreement.