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Akimasa Okuno - One of the best experts on this subject based on the ideXlab platform.

  • developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late Prepuberty in boys
    The Journal of Clinical Endocrinology and Metabolism, 2001
    Co-Authors: Johannes D Veldhuis, S M Pincus, R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, Yoshio Makita, Akimasa Okuno
    Abstract:

    To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early Prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume, <3 mL for at least 3 succeeding yr) and late Prepuberty (genital stage I-C: bone age, 8.7 +/- 1.8 yr; testis volume, <3 mL for up to 1 yr thereafter; P: = 0.00019), which indicates the acquisition of more regular LH release patterns in late Prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 +/- 1.0 yr; testis volume, 2.8 +/- 0.4 mL). The LH secretory process was more disorderly in mid- and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P: < 10(-)(7)), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the theoretically related bivariate cross-ApEn statistic disclosed maximal 2-hormone synchrony for LH and testosterone secretion in genital stage II (P: = 0.031), with relative deterioration of coordinate LH and testosterone release patterns both before and after. LH and FSH release became maximally synchronous at the end of Prepuberty (genital stage I-C; P: = 0.029), and FSH and testosterone synchrony peaked in pubertal stage III (P: = 0.037). As mean 24-h serum concentrations of LH, FSH, and testosterone rose transpubertally by 35-fold (LH), 68-fold (FSH), and 70-fold (testosterone), respectively, we infer that pubertal developmental stage per se rather than level of hormone output dictates coordinate GnRH-LH/FSH-testosterone secretion. In summary, in eugonadal boys, the regularity of 24-h LH and testosterone secretory patterns undergoes well defined pubertal stage-specific control. No sexually developmentally delimited regulation is inferable for FSH. The concept of temporally biphasic puberty-dependent variations in neurohormone secretory regularity contrasts with the unidirectional rise in daily hormone output. Accordingly, we infer that late Prepuberty and early puberty (Tanner genital stages IC and II) embody a physiologically unique sexual developmental window, marked by transiently enhanced LH and testosterone feedback stability in boys. Whether analogous plasticity of hypothalamo-pituitary-gonadal interactions unfolds during female adolescence is not known.

  • Developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late Prepuberty in boys.
    The Journal of clinical endocrinology and metabolism, 2001
    Co-Authors: Johannes D Veldhuis, S M Pincus, R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, Yoshio Makita, Akimasa Okuno
    Abstract:

    To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early Prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume,

  • DIURNAL RHYTHMS OF TESTOSTERONE AND LUTEINIZING HORMONE IN BOYS BEFORE AND DURING THE ONSET OF PUBERTY
    Pediatric Research, 1993
    Co-Authors: R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, H Ohmi, Akimasa Okuno
    Abstract:

    Secretory rhythms in LH and testosterone (T) before and during the onset of puberty were studied. Forty boys (28 prepubertal and 12 pubertal) with short stature aged 4.4 to 19.3 yr participated to this study. Blood samples for LH and T measurements were drawn every 20 min for 24 h after obtaining consent. AH the subjects were followed up by measuring height and weight and evaluating pubertal development every 3 months for 1 to 7 yr (mean 3.4 yr). There were definite diurnal rhythms in both LH and T in all of the subjects. Serum T showed maximum level at 0400-0800 h which delayed to the LH peak, decreased gradually and attained minimum level at 2000-2400 h. The ratio of T levels during 0400-0800 h period to the whole 24-h were 1.38 ± 0.16 (mean ± SD) at Prepuberty and it rose to 1.87 ± 0.08 at midpuberty. Mean 24 h LH levels rose with age; they were 0.15, 0.76 and 0.98 IU/l at 1-2 yr before, at 0-1 yr before and at the time of onset of puberty, respectively. There were no significant changes in LH pulse frequency with the pubertal development. All of the 40 boys showed positive cross-correlation between the LH and T concentrations. Mean lag time of the diurnal rhythms in T to LH was 7.1 ± 2.8 h at Prepuberty. It decreased with developing puberty and came to 1.4 ± 0.9 h at midpuberty. In conclusion, the diurnal rhythms of T and LH are already exist before the onset of puberty. There is a delay in the diurnal rhythm of T to LH and the lag time decreases with developing puberty.

Alicia Belgorosky - One of the best experts on this subject based on the ideXlab platform.

  • relationship between the growth hormone insulin like growth factor i axis insulin sensitivity and adrenal androgens in normal prepubertal and pubertal girls
    The Journal of Clinical Endocrinology and Metabolism, 2003
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent girls. A total of 61 normal girls were evaluated in Prepuberty [Group (Gr)1, n = 33; early (Gr1A, n = 16) and late (Gr1B, n = 17)]; puberty (Gr3, n = 28), early (Gr3A, n = 9) and late (Gr3B, n = 19); and during the transition between Prepuberty and puberty (Gr2, n = 26). Insulin sensitivity was estimated by the fasting glucose/insulin ratio (G/I). In Gr1, G/I was significantly higher, and the mean serum IGF-I and serum dehydroepiandrosterone sulfate (DHEAS) were significantly lower than in Gr3 (P < 0.0001). Mean G/I in Gr1A and Gr3A was significantly higher than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and ratios in Gr1B were also significantly higher than in Gr3A (P < 0.02). However, body mass index (BMI) in Gr1A, Gr1B, and Gr3A was not significantly different, although a significant increment was observed between late Prepuberty (Gr1B) and late puberty (Gr3B; P < 0.0001). On the other hand, serum IGF-I levels in Gr1A and Gr3A were significantly lower than those in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively. The mean serum DHEAS level in Gr1A and Gr3A was significantly lower than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and the level in Gr1B was also significantly lower than in Gr3A (P < 0.02). Correlation studies within Gr1, Gr2, and Gr3 were also performed. There was a significant positive correlation between serum DHEAS and age and a significant negative correlation between serum DHEAS and G/I in the three groups. However, a significant positive correlation between serum DHEAS and serum IGF-I was only found in Gr1. Furthermore, a significant negative correlation between BMI and the G/I was found in Gr2 and Gr3. Therefore, changes in insulin sensitivity might be involved in adrenal androgen synthesis both in Prepuberty and in puberty, as well as during the transition from Prepuberty to puberty. Changes in BMI suggest that adiposity might be a mediator of this effect, particularly during late puberty. On the other hand, the GH/IGF axis might be an important metabolic signal involved in the maturational changes of human adrenal androgens during Prepuberty, at the time of adrenarche. Indeed, a significant negative correlation between G/I and serum IGF-I was found in Gr1, as well as in Gr2. In conclusion, the findings of this study indicate that the GH/IGF-I axis and insulin resistance might be involved in the mechanism of adrenarche during Prepuberty in normal girls. Because these relationships had not been seen in boys, we proposed that prepubertal ovarian estrogens might be responsible for the sex difference. The relationship between insulin resistance and adrenal androgens persists during the transition from Prepuberty to puberty, as well as during puberty.

  • Relationship between the growth hormone/insulin-like growth factor-I axis, insulin sensitivity, and adrenal androgens in normal prepubertal and pubertal girls
    The Journal of clinical endocrinology and metabolism, 2003
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent girls. A total of 61 normal girls were evaluated in Prepuberty [Group (Gr)1, n = 33; early (Gr1A, n = 16) and late (Gr1B, n = 17)]; puberty (Gr3, n = 28), early (Gr3A, n = 9) and late (Gr3B, n = 19); and during the transition between Prepuberty and puberty (Gr2, n = 26). Insulin sensitivity was estimated by the fasting glucose/insulin ratio (G/I). In Gr1, G/I was significantly higher, and the mean serum IGF-I and serum dehydroepiandrosterone sulfate (DHEAS) were significantly lower than in Gr3 (P < 0.0001). Mean G/I in Gr1A and Gr3A was significantly higher than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and ratios in Gr1B were also significantly higher than in Gr3A (P < 0.02). However, body mass index (BMI) in Gr1A, Gr1B, and Gr3A was not significantly different, although a significant increment was observed between late Prepuberty (Gr1B) and late puberty (Gr3B; P < 0.0001). On the other hand, serum IGF-I levels in Gr1A and Gr3A were significantly lower than those in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively. The mean serum DHEAS level in Gr1A and Gr3A was significantly lower than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and the level in Gr1B was also significantly lower than in Gr3A (P < 0.02). Correlation studies within Gr1, Gr2, and Gr3 were also performed. There was a significant positive correlation between serum DHEAS and age and a significant negative correlation between serum DHEAS and G/I in the three groups. However, a significant positive correlation between serum DHEAS and serum IGF-I was only found in Gr1. Furthermore, a significant negative correlation between BMI and the G/I was found in Gr2 and Gr3. Therefore, changes in insulin sensitivity might be involved in adrenal androgen synthesis both in Prepuberty and in puberty, as well as during the transition from Prepuberty to puberty. Changes in BMI suggest that adiposity might be a mediator of this effect, particularly during late puberty. On the other hand, the GH/IGF axis might be an important metabolic signal involved in the maturational changes of human adrenal androgens during Prepuberty, at the time of adrenarche. Indeed, a significant negative correlation between G/I and serum IGF-I was found in Gr1, as well as in Gr2. In conclusion, the findings of this study indicate that the GH/IGF-I axis and insulin resistance might be involved in the mechanism of adrenarche during Prepuberty in normal girls. Because these relationships had not been seen in boys, we proposed that prepubertal ovarian estrogens might be responsible for the sex difference. The relationship between insulin resistance and adrenal androgens persists during the transition from Prepuberty to puberty, as well as during puberty.

  • Relationship between the GH/IGF-I axis, insulin sensitivity, and adrenal androgens in normal prepubertal and pubertal boys.
    The Journal of clinical endocrinology and metabolism, 2002
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    In girls, but not in boys, pronounced adrenarche and precocious pubarche along with ovarian hyperandrogenism have been related to insulin resistance and reduced fetal growth. However, insulin secretion is increased during puberty in normal boys. The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent boys. Fifty-six normal boys were divided into the following groups (Gr): Gr1, Prepuberty (testicular volume,

R Mitamura - One of the best experts on this subject based on the ideXlab platform.

  • developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late Prepuberty in boys
    The Journal of Clinical Endocrinology and Metabolism, 2001
    Co-Authors: Johannes D Veldhuis, S M Pincus, R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, Yoshio Makita, Akimasa Okuno
    Abstract:

    To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early Prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume, <3 mL for at least 3 succeeding yr) and late Prepuberty (genital stage I-C: bone age, 8.7 +/- 1.8 yr; testis volume, <3 mL for up to 1 yr thereafter; P: = 0.00019), which indicates the acquisition of more regular LH release patterns in late Prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 +/- 1.0 yr; testis volume, 2.8 +/- 0.4 mL). The LH secretory process was more disorderly in mid- and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P: < 10(-)(7)), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the theoretically related bivariate cross-ApEn statistic disclosed maximal 2-hormone synchrony for LH and testosterone secretion in genital stage II (P: = 0.031), with relative deterioration of coordinate LH and testosterone release patterns both before and after. LH and FSH release became maximally synchronous at the end of Prepuberty (genital stage I-C; P: = 0.029), and FSH and testosterone synchrony peaked in pubertal stage III (P: = 0.037). As mean 24-h serum concentrations of LH, FSH, and testosterone rose transpubertally by 35-fold (LH), 68-fold (FSH), and 70-fold (testosterone), respectively, we infer that pubertal developmental stage per se rather than level of hormone output dictates coordinate GnRH-LH/FSH-testosterone secretion. In summary, in eugonadal boys, the regularity of 24-h LH and testosterone secretory patterns undergoes well defined pubertal stage-specific control. No sexually developmentally delimited regulation is inferable for FSH. The concept of temporally biphasic puberty-dependent variations in neurohormone secretory regularity contrasts with the unidirectional rise in daily hormone output. Accordingly, we infer that late Prepuberty and early puberty (Tanner genital stages IC and II) embody a physiologically unique sexual developmental window, marked by transiently enhanced LH and testosterone feedback stability in boys. Whether analogous plasticity of hypothalamo-pituitary-gonadal interactions unfolds during female adolescence is not known.

  • Developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late Prepuberty in boys.
    The Journal of clinical endocrinology and metabolism, 2001
    Co-Authors: Johannes D Veldhuis, S M Pincus, R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, Yoshio Makita, Akimasa Okuno
    Abstract:

    To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early Prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume,

  • DIURNAL RHYTHMS OF TESTOSTERONE AND LUTEINIZING HORMONE IN BOYS BEFORE AND DURING THE ONSET OF PUBERTY
    Pediatric Research, 1993
    Co-Authors: R Mitamura, K Yano, Naoki Suzuki, Yoshiya Ito, H Ohmi, Akimasa Okuno
    Abstract:

    Secretory rhythms in LH and testosterone (T) before and during the onset of puberty were studied. Forty boys (28 prepubertal and 12 pubertal) with short stature aged 4.4 to 19.3 yr participated to this study. Blood samples for LH and T measurements were drawn every 20 min for 24 h after obtaining consent. AH the subjects were followed up by measuring height and weight and evaluating pubertal development every 3 months for 1 to 7 yr (mean 3.4 yr). There were definite diurnal rhythms in both LH and T in all of the subjects. Serum T showed maximum level at 0400-0800 h which delayed to the LH peak, decreased gradually and attained minimum level at 2000-2400 h. The ratio of T levels during 0400-0800 h period to the whole 24-h were 1.38 ± 0.16 (mean ± SD) at Prepuberty and it rose to 1.87 ± 0.08 at midpuberty. Mean 24 h LH levels rose with age; they were 0.15, 0.76 and 0.98 IU/l at 1-2 yr before, at 0-1 yr before and at the time of onset of puberty, respectively. There were no significant changes in LH pulse frequency with the pubertal development. All of the 40 boys showed positive cross-correlation between the LH and T concentrations. Mean lag time of the diurnal rhythms in T to LH was 7.1 ± 2.8 h at Prepuberty. It decreased with developing puberty and came to 1.4 ± 0.9 h at midpuberty. In conclusion, the diurnal rhythms of T and LH are already exist before the onset of puberty. There is a delay in the diurnal rhythm of T to LH and the lag time decreases with developing puberty.

Reinhard W. Holl - One of the best experts on this subject based on the ideXlab platform.

  • Tracking of Metabolic Control from Childhood to Young Adulthood in Type 1 Diabetes
    The Journal of pediatrics, 2014
    Co-Authors: Sabine E. Hofer, Klemens Raile, Elke Fröhlich-reiterer, Thomas Kapellen, Axel Dost, Joachim Rosenbauer, Jürgen Grulich-henn, Reinhard W. Holl
    Abstract:

    medianglycatedhemoglobinA1c(HbA1c)was7.5(IQR6.8-8.3),duringpuberty8.0(IQR7.3-8.9),andafterpuberty7.8 (IQR 7.1-9.0). A significant intra-individual correlation was found for Prepuberty to puberty HbA1c levels (R = 0.55, P < .001), puberty to adulthood (R = 0.59, P < .001), as well as Prepuberty to adulthood (R = 0.30, P < .001). When patients were divided into tertiles of prepubertal HbA1c, HbA1c increased in all 3 groups over time, however, significant groupdifferencestrackedintoadulthood(P

Gabriela Guercio - One of the best experts on this subject based on the ideXlab platform.

  • Androgen Insensitivity Syndrome at Prepuberty: Marked Loss of Spermatogonial Cells at Early Childhood and Presence of Gonocytes up to Puberty.
    Sexual development : genetics molecular biology evolution endocrinology embryology and pathology of sex determination and differentiation, 2017
    Co-Authors: Paula Aliberti, Gabriela Guercio, Natalia Perez Garrido, Roxana Marino, Pablo Ramirez, Alberto J. Solari, Roberta B. Sciurano, Mariana Costanzo, Diana Monica Warman, Marcela Bailez
    Abstract:

    Androgen insensitivity syndrome (AIS) is a hereditary condition in patients with a 46,XY karyotype in which loss-of-function mutations of the androgen receptor (AR) gene are responsible for defects in virilization. The aim of this study was to investigate the consequences of the lack of AR activity on germ cell survival and the degree of testicular development reached by these patients by analyzing gonadal tissue from patients with AIS prior to Sertoli cell maturation at puberty. Twenty-three gonads from 13 patients with AIS were assessed and compared to 18 testes from 17 subjects without endocrine disorders. The study of the gonadal structure using conventional microscopy and the ultrastructural characteristics of remnant germ cells using electron microscopy, combined with the immunohistochemical analysis of specific germ cell markers (MAGE-A4 for premeiotic germ cells and of OCT3/4 for gonocytes), enabled us to carry out a thorough investigation of germ cell life in an androgen-insensitive microenvironment throughout Prepuberty until young adulthood. Here, we show that germ cell degeneration starts very early, with a marked decrease in number after only 2 years of life, and we demonstrate the permanence of gonocytes in AIS testis samples until puberty, describing 2 different populations. Additionally, our results provide further evidence for the importance of AR signaling in peritubular myoid cells during Prepuberty to maintain Sertoli and spermatogonial cell health and survival.

  • relationship between the growth hormone insulin like growth factor i axis insulin sensitivity and adrenal androgens in normal prepubertal and pubertal girls
    The Journal of Clinical Endocrinology and Metabolism, 2003
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent girls. A total of 61 normal girls were evaluated in Prepuberty [Group (Gr)1, n = 33; early (Gr1A, n = 16) and late (Gr1B, n = 17)]; puberty (Gr3, n = 28), early (Gr3A, n = 9) and late (Gr3B, n = 19); and during the transition between Prepuberty and puberty (Gr2, n = 26). Insulin sensitivity was estimated by the fasting glucose/insulin ratio (G/I). In Gr1, G/I was significantly higher, and the mean serum IGF-I and serum dehydroepiandrosterone sulfate (DHEAS) were significantly lower than in Gr3 (P < 0.0001). Mean G/I in Gr1A and Gr3A was significantly higher than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and ratios in Gr1B were also significantly higher than in Gr3A (P < 0.02). However, body mass index (BMI) in Gr1A, Gr1B, and Gr3A was not significantly different, although a significant increment was observed between late Prepuberty (Gr1B) and late puberty (Gr3B; P < 0.0001). On the other hand, serum IGF-I levels in Gr1A and Gr3A were significantly lower than those in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively. The mean serum DHEAS level in Gr1A and Gr3A was significantly lower than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and the level in Gr1B was also significantly lower than in Gr3A (P < 0.02). Correlation studies within Gr1, Gr2, and Gr3 were also performed. There was a significant positive correlation between serum DHEAS and age and a significant negative correlation between serum DHEAS and G/I in the three groups. However, a significant positive correlation between serum DHEAS and serum IGF-I was only found in Gr1. Furthermore, a significant negative correlation between BMI and the G/I was found in Gr2 and Gr3. Therefore, changes in insulin sensitivity might be involved in adrenal androgen synthesis both in Prepuberty and in puberty, as well as during the transition from Prepuberty to puberty. Changes in BMI suggest that adiposity might be a mediator of this effect, particularly during late puberty. On the other hand, the GH/IGF axis might be an important metabolic signal involved in the maturational changes of human adrenal androgens during Prepuberty, at the time of adrenarche. Indeed, a significant negative correlation between G/I and serum IGF-I was found in Gr1, as well as in Gr2. In conclusion, the findings of this study indicate that the GH/IGF-I axis and insulin resistance might be involved in the mechanism of adrenarche during Prepuberty in normal girls. Because these relationships had not been seen in boys, we proposed that prepubertal ovarian estrogens might be responsible for the sex difference. The relationship between insulin resistance and adrenal androgens persists during the transition from Prepuberty to puberty, as well as during puberty.

  • Relationship between the growth hormone/insulin-like growth factor-I axis, insulin sensitivity, and adrenal androgens in normal prepubertal and pubertal girls
    The Journal of clinical endocrinology and metabolism, 2003
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent girls. A total of 61 normal girls were evaluated in Prepuberty [Group (Gr)1, n = 33; early (Gr1A, n = 16) and late (Gr1B, n = 17)]; puberty (Gr3, n = 28), early (Gr3A, n = 9) and late (Gr3B, n = 19); and during the transition between Prepuberty and puberty (Gr2, n = 26). Insulin sensitivity was estimated by the fasting glucose/insulin ratio (G/I). In Gr1, G/I was significantly higher, and the mean serum IGF-I and serum dehydroepiandrosterone sulfate (DHEAS) were significantly lower than in Gr3 (P < 0.0001). Mean G/I in Gr1A and Gr3A was significantly higher than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and ratios in Gr1B were also significantly higher than in Gr3A (P < 0.02). However, body mass index (BMI) in Gr1A, Gr1B, and Gr3A was not significantly different, although a significant increment was observed between late Prepuberty (Gr1B) and late puberty (Gr3B; P < 0.0001). On the other hand, serum IGF-I levels in Gr1A and Gr3A were significantly lower than those in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively. The mean serum DHEAS level in Gr1A and Gr3A was significantly lower than in Gr1B (P < 0.01) and Gr3B (P < 0.02), respectively, and the level in Gr1B was also significantly lower than in Gr3A (P < 0.02). Correlation studies within Gr1, Gr2, and Gr3 were also performed. There was a significant positive correlation between serum DHEAS and age and a significant negative correlation between serum DHEAS and G/I in the three groups. However, a significant positive correlation between serum DHEAS and serum IGF-I was only found in Gr1. Furthermore, a significant negative correlation between BMI and the G/I was found in Gr2 and Gr3. Therefore, changes in insulin sensitivity might be involved in adrenal androgen synthesis both in Prepuberty and in puberty, as well as during the transition from Prepuberty to puberty. Changes in BMI suggest that adiposity might be a mediator of this effect, particularly during late puberty. On the other hand, the GH/IGF axis might be an important metabolic signal involved in the maturational changes of human adrenal androgens during Prepuberty, at the time of adrenarche. Indeed, a significant negative correlation between G/I and serum IGF-I was found in Gr1, as well as in Gr2. In conclusion, the findings of this study indicate that the GH/IGF-I axis and insulin resistance might be involved in the mechanism of adrenarche during Prepuberty in normal girls. Because these relationships had not been seen in boys, we proposed that prepubertal ovarian estrogens might be responsible for the sex difference. The relationship between insulin resistance and adrenal androgens persists during the transition from Prepuberty to puberty, as well as during puberty.

  • Relationship between the GH/IGF-I axis, insulin sensitivity, and adrenal androgens in normal prepubertal and pubertal boys.
    The Journal of clinical endocrinology and metabolism, 2002
    Co-Authors: Gabriela Guercio, Marco A Rivarola, E Chaler, Mercedes Maceiras, Alicia Belgorosky
    Abstract:

    In girls, but not in boys, pronounced adrenarche and precocious pubarche along with ovarian hyperandrogenism have been related to insulin resistance and reduced fetal growth. However, insulin secretion is increased during puberty in normal boys. The aim of this study was to analyze the possible implication of changes in the GH/IGF-I axis and in insulin sensitivity for the regulation of adrenal androgen secretion of normal prepubertal and adolescent boys. Fifty-six normal boys were divided into the following groups (Gr): Gr1, Prepuberty (testicular volume,