Intrauterine growth retardation predisposes to insulin resistance but not to hyperandrogenism in young women

Characterization of the ability of a, second-generation SST-DA chimeric molecule, TBR-065, to suppress GH secretion from human GH-secreting adenoma cells

CONTEXT

Somatostatin (SST) and dopamine (DA) inhibit growth hormone (GH) secretion and proliferation of GH-secreting pituitary adenomas (GHomas) through binding to SSTR2 and D2R receptors. Chimeric SST-DA compounds (Dopastatins) display increased potency in inhibiting GH secretion, as compared with individual SST or DA analogs (alone or combined).

OBJECTIVE

To assess the efficacy of a second-generation dopastatin, TBR-065, in suppressing GH secretion from human GH- and GH/prolactin(PRL)-omas.

DESIGN

We compared the ability of TBR-065 to inhibit GH secretion from primary cultures of human GH- or GH/PRLoma cells to that of the first generation dopastatin, TBR-760 (formerly BIM-23A760), octreotide (OCT) and cabergoline (CAB), the later either alone or combined. We investigated whether there was any impact of BIM-133, the metabolite of TBR-065, on the ability of TBR-065 to inhibit GH in these cultures.

METHODS

17 GH- and GH/PRLomas were included in this study. Inhibition of GH secretion by TBR-065, TBR-760, OCT and CAB (0.1 pM to 0.1 µM) was assessed over a period of 8 h.

RESULTS

All tumors expressed SSTR2 and D2R mRNAs. GH suppression was higher with TBR-065 as compared with TBR-760 (E_max = 57 ± 5.6% vs. 41.1 ± 12.5%, respectively, p < 0.001) or with OCT + CAB (E_max = 56.8 ± 7.2% vs. 44.4 ± 9.4%, p < 0.001). BIM-133 did not have any impact on the activity of TBR-065.

CONCLUSION

TBR-065 has significantly improved efficacy in suppressing GH secretion as compared to current available therapies and may represent a new promising option for the treatment of acromegaly.

High DHEAS Level in Girls Is Associated with Earlier Pubertal Maturation and Mild Increase in Androgens throughout Puberty without Affecting Postmenarche Ovarian Morphology

OBJECTIVE

To assess whether the presence of high DHEAS (HD) at 7 years determines different timing, sequence, and rate of pubertal events, and whether it is associated with adrenal and/or ovarian hyperandrogenism and changes in ovarian morphology throughout puberty.

METHODS

In a longitudinal study of 504 girls, clinical evaluation was performed every 6 months after 7 years of age to detect Tanner stages; hormonal and anthropometric measurements were conducted at thelarche (B2), breast Tanner 4 (B4), and 1 year after menarche; ultrasonographic evaluation was also performed after menarche. The girls were classified as HD if their DHEAS level was >42.1 µg/dL (>75th percentile) around 7 years.

RESULTS

HD around 7 years is associated with a younger age at thelarche, pubarche, and menarche. Girls with HD had higher androstenedione and total testosterone levels, and a higher free androgen index (FAI), and lower levels of antimüllerian hormone (AMH) at B2, and higher levels of androstenedione and FAI at B4 and after menarche. All these results were significant even after adjusting for body mass index, age at first DHEAS determination, and birth weight. One year after menarche, polycystic ovarian morphology was detected in 7.6 and 7.3% of the HD and the normal DHEAS group, respectively. Ovarian volume was correlated with AMH, testosterone, androstenedione, and LH but not with DHEAS around 7 years.

CONCLUSION

Prepubertal HD in normal girls was associated with earlier thelarche, pubarche, and menarche, and a mild androgen increase throughout puberty. We believe continuous follow-up of this cohort is important to prospectively address the interrelationships between biochemical adrenarche and early growth as determinants of ovarian function.

Birth weight and polycystic ovary syndrome in adult life: is there a causal link?

Objectives

Several studies have demonstrated associations of birth weight with metabolic and reproductive abnormalities in adults. The aim of this study was to investigate the birth weight in women with PCOS and its correlation with clinical and biochemical characteristics of the syndrome.

Materials and Methods

We studied 288 women with PCOS according to the NIH criteria and 166 women with normal cycle and without clinical hyperandrogenism. Birth weight and anthropometric characteristics were recorded, and levels of serum androgens, SHBG, insulin and fasting glucose were measured.

Results

Birth weight data were available for 243/288 women with PCOS and age- and BMI-matched 101/166 controls. No differences were found (p> 0.05) in birth weight among women with PCOS and normal controls. Birth weight of PCOS women was negatively correlated with DHEAS levels (p = 0.031, r = -0.143) and positively correlated with waist circumference (p <0.001, r = 0.297) and body mass index (BMI) (p = 0.040, r = 0.132). Birth weight of controls was negatively correlated with SHBG levels (p = 0.021, r = -0.234). Women from both groups were further divided in 6 categories according to birth weight (A. <2.500 gr, B. 2.501-3.000 gr, C. 3.001-3.500 gr, D. 3.501-4.000 gr, E. 4.001-4.500 gr, F. > 4.500 gr). No statistically significant differences were observed in the distribution percentages between PCOS women and controls. (A. 7% vs 7.9%, B. 26.8% vs 20.8%, C. 39.1% vs 48.5%, D. 21.4% vs 20.8%, E. 4.9% vs 2%, F. 0.8% vs 0%), (in all comparisons, p> 0.05).

Conclusions

Women with PCOS do not differ from controls in birth weight distribution. However, birth weight may contribute to subtypes of the syndrome that are characterized by adrenal hyperandrogenism and central obesity.

Premature adrenarche: etiology, clinical findings, and consequences

Adrenarche means the morphological and functional change of the adrenal cortex leading to increasing production of adrenal androgen precursors (AAPs) in mid childhood, typically at around 5-8 years of age in humans. The AAPs dehydroepiandrosterone (DHEA) and its sulfate conjugate (DHEAS) are the best serum markers of adrenal androgen (AA) secretion and adrenarche. Normal ACTH secretion and action are needed for adrenarche, but additional inherent and exogenous factors regulate AA secretion. Inter-individual variation in the timing of adrenarche and serum concentrations of DHEA(S) in adolescence and adulthood are remarkable. Premature adrenarche (PA) is defined as the appearance of clinical signs of androgen action (pubic/axillary hair, adult type body odor, oily skin or hair, comedones, acne, accelerated statural growth) before the age of 8 years in girls or 9 years in boys associated with AAP concentrations high for the prepubertal chronological age. To accept the diagnosis of PA, central puberty, adrenocortical and gonadal sex hormone secreting tumors, congenital adrenal hyperplasia, and exogenous source of androgens need to be excluded. The individually variable peripheral conversion of circulating AAPs to biologically more active androgens (testosterone, dihydrotestosterone) and the androgen receptor activity in the target tissues are as important as the circulating AAP concentrations as determinants of androgen action. PA has gained much attention during the last decades, as it has been associated with small birth size, the metabolic and polycystic ovarian syndrome (PCOS), and thus with an increased risk for type 2 diabetes and cardiovascular diseases in later life. The aim of this review is to describe the known hormonal changes and their possible regulators in on-time and premature adrenarche, and the clinical features and possible later health problems associating with PA.

Ontogeny of polycystic ovary syndrome and insulin resistance in utero and early childhood

Polycystic ovary syndrome (PCOS) is a prevalent hyperandrogenic infertility and cardiometabolic disorder that increases a woman's lifetime risk of type 2 diabetes mellitus. It is heritable and intensely familial. Progress toward a cure has been delayed by absence of an etiology. Evidence is mounting, however, for in utero T excess, together with gestational hyperglycemia, contributing to either early differentiation of PCOS or phenotypic amplification of its genotypes. Abnormal endocrine, ovarian, and hyperinsulinemic traits are detectable as early as 2 months of age in daughters of women with PCOS, with adiposity enhancement of hyperinsulinemia during childhood potentially contributing to hyperandrogenism and LH excess by adolescence. These findings encourage increasing clinical focus on early childhood markers for adiposity and hyperinsulinemia accompanying ovarian and adrenal endocrine abnormalities that precede a diagnosable PCOS phenotype. They raise the possibility for lifestyle or therapeutic intervention before and during pregnancy or during childhood and adolescence alleviating the manifestations of a familial genetic predisposition to PCOS.

Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications

Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.

Latin American consensus: children born small for gestational age

BACKGROUND

Children born small for gestational age (SGA) experience higher rates of morbidity and mortality than those born appropriate for gestational age. In Latin America, identification and optimal management of children born SGA is a critical issue. Leading experts in pediatric endocrinology throughout Latin America established working groups in order to discuss key challenges regarding the evaluation and management of children born SGA and ultimately develop a consensus statement.

DISCUSSION

SGA is defined as a birth weight and/or birth length greater than 2 standard deviations (SD) below the population reference mean for gestational age. SGA refers to body size and implies length-weight reference data in a geographical population whose ethnicity is known and specific to this group. Ideally, each country/region within Latin America should establish its own standards and make relevant updates. SGA children should be evaluated with standardized measures by trained personnel every 3 months during year 1 and every 6 months during year 2. Those without catch-up growth within the first 6 months of life need further evaluation, as do children whose weight is ≤ -2 SD at age 2 years. Growth hormone treatment can begin in SGA children > 2 years with short stature (< -2.0 SD) and a growth velocity < 25th percentile for their age, and should continue until final height (a growth velocity below 2 cm/year or a bone age of > 14 years for girls and > 16 years for boys) is reached. Blood glucose, thyroid function, HbA1c, and insulin-like growth factor-1 (IGF-1) should be monitored once a year. Monitoring insulin changes from baseline and surrogates of insulin sensitivity is essential. Reduced fetal growth followed by excessive postnatal catch-up in height, and particularly in weight, should be closely monitored. In both sexes, gonadal function should be monitored especially during puberty.

SUMMARY

Children born SGA should be carefully followed by a multidisciplinary group that includes perinatologists, pediatricians, nutritionists, and pediatric endocrinologists since 10% to 15% will continue to have weight and height deficiency through development and may benefit from growth hormone treatment. Standards/guidelines should be developed on a country/region basis throughout Latin America.

Fetal origins of adult disease

Dr. David Barker first popularized the concept of fetal origins of adult disease (FOAD). Since its inception, FOAD has received considerable attention. The FOAD hypothesis holds that events during early development have a profound impact on one's risk for development of future adult disease. Low birth weight, a surrogate marker of poor fetal growth and nutrition, is linked to coronary artery disease, hypertension, obesity, and insulin resistance. Clues originally arose from large 20th century, European birth registries. Today, large, diverse human cohorts and various animal models have extensively replicated these original observations. This review focuses on the pathogenesis related to FOAD and examines Dr. David Barker's landmark studies, along with additional human and animal model data. Implications of the FOAD extend beyond the low birth weight population and include babies exposed to stress, both nutritional and nonnutritional, during different critical periods of development, which ultimately result in a disease state. By understanding FOAD, health care professionals and policy makers will make this issue a high health care priority and implement preventive measures and treatment for those at higher risk for chronic diseases.

Birthweight and body size throughout life in relation to sex hormones and prolactin concentrations in premenopausal women

The association of birthweight and body size throughout life with premenopausal breast cancer risk may be due, in part, to relationships with sex hormones. Therefore, we assessed whether birthweight, body shape at ages 5 and 10, body mass index (BMI) at age 18 and adulthood, adult waist circumference and waist-to-hip ratio (WHR), and attained height were associated with the plasma concentrations of estrogens, androgens, progesterone, prolactin, and sex hormone-binding globulin (SHBG) in 592 premenopausal women, ages 33 to 52 years old, from the Nurses' Health Study II. About 85% of women provided blood samples during follicular and luteal menstrual phases; other women had a single untimed sample. We observed few associations between sex hormone levels and birthweight or body shape in childhood. However, adult BMI was inversely associated with SHBG (P trend < 0.001) and positively associated with free testosterone (P trend < 0.001) concentrations. Adult BMI was not associated with follicular or luteal free estradiol levels (P trend >or= 0.15) because it was inversely associated with total estradiol levels (P trend < 0.001 for follicular and luteal estradiol levels). Testosterone, androstenedione, and progesterone were inversely associated with BMI. Comparing women with a BMI of >or=30 versus <20 kg/m2, levels were higher by 53% for free testosterone and lower by 51% for SHBG, 39% for follicular estradiol, 20% for luteal estradiol, 14% for androstenedione, 13% for testosterone, and 20% for progesterone. We observed no clear associations between BMI at age 18, waist circumference, WHR, or height, and sex hormone concentrations. Our results suggest that effects on premenopausal sex hormone levels may be one mechanism through which adult adiposity, but not birthweight or childhood body size, affects premenopausal breast cancer risk.

Small for gestational age: short stature and beyond

Depending on the definitions used, up to 10% of all live-born neonates are small for gestational age (SGA). Although the vast majority of these children show catch-up growth by 2 yr of age, one in 10 does not. It is increasingly recognized that those who are born SGA are at risk of developing metabolic disease later in life. Reduced fetal growth has been shown to be associated with an increased risk of insulin resistance, obesity, cardiovascular disease, and type 2 diabetes mellitus. The majority of pathology is seen in adults who show spontaneous catch-up growth as children. There is evidence to suggest that some of the metabolic consequences of intrauterine growth retardation in children born SGA can be mitigated by ensuring early appropriate catch-up growth, while avoiding excessive weight gain. Implicitly, this argument questions current infant formula feeding practices. The risk is less clear for individuals who do not show catch-up growth and who are treated with GH for short stature. Recent data, however, suggest that long-term treatment with GH does not increase the risk of type 2 diabetes mellitus and the metabolic syndrome in young adults born SGA.

Comparison of clinical, ultrasonographic, and biochemical differences at the beginning of puberty in healthy girls born either small for gestational age or appropriate for gestational age: preliminary results

CONTEXT

There are limited and controversial data concerning puberty characteristics in girls born small for gestational age (SGA).

OBJECTIVE

The objective of the study was to document clinical, ultrasonographic, and biochemical characteristics at the beginning of puberty in matched healthy girls born either SGA or appropriate for gestational age (AGA) recruited from the community.

PATIENTS

Inclusion criteria were breast Tanner stage II and a body mass index between the 10th and 95th percentiles.

INTERVENTIONS

Recruited subjects underwent a complete physical exam, bone age, and ultrasound measurements of the internal genitalia. Hormonal assessment included fasting early morning dehydroepiandrosterone sulfate, androstenedione, SHBG, inhibin-B, FSH, LH, estradiol (E2), 17-hydroxyprogesterone (17OH Prog), and testosterone. Thereafter, a GnRH agonist test (leuprolide 500 microg, sc) was performed with FSH and LH at time 3 and 24 h for E2, 17OH Prog, and testosterone.

RESULTS

Sixty-five girls (35 AGA, 30 SGA) with a mean age of 9.9 +/- 1.03 (7.8-12.5) yr, similar bone age/chronological age (1.02 +/- 0.8 in AGA and 1 +/- 0.76 in SGA), median height of 1.35 +/- 0.06 cm, and similar waist to hip ratio were included. No differences in the presence of pubic hair, axillary hair, apocrine odor, or ultrasound measurements were found. SGA girls had increased baseline E2 as well as stimulated E2 and 17OH Prog.

CONCLUSIONS

In a preliminary sample of lean, healthy girls recruited from the community born either SGA or AGA, we observed slight hormonal differences at the beginning of puberty. Longitudinal follow-up of this cohort will allow us to understand whether these differences are maintained and have a clinical impact in their pubertal development.

The molecular-genetic basis of functional hyperandrogenism and the polycystic ovary syndrome

The genetic mechanisms underlying functional hyperandrogenism and the polycystic ovary syndrome (PCOS) remain largely unknown. Given the large number of genetic variants found in association with these disorders, the emerging picture is that of a complex multigenic trait in which environmental influences play an important role in the expression of the hyperandrogenic phenotype. Among others, genomic variants in genes related to the regulation of androgen biosynthesis and function, insulin resistance, and the metabolic syndrome, and proinflammatory genotypes may be involved in the genetic predisposition to functional hyperandrogenism and PCOS. The elucidation of the molecular genetic basis of these disorders has been burdened by the heterogeneity in the diagnostic criteria used to define PCOS, the limited sample size of the studies conducted to date, and the lack of precision in the identification of ethnic and environmental factors that trigger the development of hyperandrogenic disorders. Progress in this area requires adequately sized multicenter collaborative studies after standardization of the diagnostic criteria used to classify hyperandrogenic patients, in whom modifying environmental factors such as ethnicity, diet, and lifestyle are identified with precision. In addition to classic molecular genetic techniques such as linkage analysis in the form of a whole-genome scan and large case-control studies, promising genomic and proteomic approaches will be paramount to our understanding of the pathogenesis of functional hyperandrogenism and PCOS, allowing a more precise prevention, diagnosis, and treatment of these prevalent disorders.

Genetic Basis of Metabolic Abnormalities in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder characterized by hyperandrogenism and chronic anovulation. The syndrome is frequently associated with an increased risk for insulin resistance and type 2 diabetes mellitus; obesity exacerbates insulin resistance and favors the progression from impaired glucose tolerance to diabetes in these patients. In young women, precocious pubarche and hyperinsulinemia are early manifestations of PCOS. The familial clustering of women with PCOS suggests that heredity is implicated in the origin of the syndrome. However, genetic approaches to its pathogenesis have been hampered by the heterogeneity of phenotypic features within families, and the lack of uniform criteria for diagnosis. Currently, PCOS is considered a polygenic trait that might result from the interaction of susceptibility and protective genomic variants under the influence of environmental factors. Both linkage analysis and association studies are valid tools for the study of the genetics of PCOS. Candidate genes for PCOS include those related to androgenic pathways and metabolic associations of the syndrome. More recently, genes encoding inflammatory cytokines have been identified as target genes for PCOS, as proinflammatory genotypes and phenotypes are also associated with obesity, insulin resistance, type 2 diabetes, PCOS, and increased cardiovascular risk. This paper reviews the candidate genes involved in the metabolic pathways that are altered in patients with PCOS. Despite a significant amount of research in this area, none of the genes studied so far has been identified as the PCOS susceptibility gene for the majority of cases. PCOS is the first component of the metabolic syndrome to be detected in many women, so the identification and correct diagnosis of PCOS has important preventive and therapeutic implications for the affected women and their families. In the future, new therapeutic approaches to PCOS will rely on knowing the genes, environmental influences, and etiologic mechanisms associated with the disorder.

Endocrine-Related Causes and Consequences of Intrauterine Growth Retardation

The term intrauterine growth retardation (IUGR) is assigned to newborns born with a birth weight and/or birth length below the tenth percentile for their gestational age. Intrauterine growth retardation is usually due to maternal, fetal factors, or placental insufficiency, while endocrine factors represent just a small minority in its etiology. Main endocrine-related causes of IUGR are disorders in insulin or insulin-like growth factor-I (IGF-I) secretion or action. Newborns with IUGR are at increased risk to develop a metabolic syndrome later in life, namely obesity, arterial hypertension, hypercholesterolemia, cardiovascular disease, impaired glucose tolerance, or diabetes mellitus type 2. This association is the result of the adaptational changes of the fetal endocrine-metabolic mechanisms to the impaired intrauterine milieu to assure survival in the short term. The persistence of these changes after birth can be detrimental in adult life. Furthermore, premature adrenarche, as well as ovarian hyperandrogenism, seem to be associated with IUGR in girls, demonstrating that IUGR may have long-lasting effects on both somatic health and reproductive function. Finally, the intrauterine exposure of the fetus to stressors may affect the individual's ability to face stress in postnatal life. Therefore, if optimization of somatic and psychosocial well-being of the individual is the golden goal of medicine, special attention should be paid to maintain an optimal intrauterine milieu devoid of any stressors with adequate nutrient supply and to reserve ideal psychosocial support to the pregnant woman.

Is birth weight related to later glucose and insulin metabolism?--A systematic review

AIM

To determine the relationship of birth weight to later glucose and insulin metabolism.

METHODS

Systematic review of the published literature. Data sources were Medline and Embase. Included studies were papers reporting the relationship of birth weight with a measure of glucose or insulin metabolism after 1 year of age, including the prevalence of Type 2 diabetes mellitus (DM). Three reviewers abstracted information from each paper according to specified criteria.

RESULTS

Forty-eight papers fulfilled the criteria for inclusion, mostly of adults in developed countries. Most studies reported an inverse relationship between birth weight and fasting plasma glucose concentrations (15 of 25 papers), fasting plasma insulin concentrations (20 of 26), plasma glucose concentrations 2 h after a glucose load (20 of 25), the prevalence of Type 2 DM (13 of 16), measures of insulin resistance (17 of 22), and measures of insulin secretion (16 of 24). The predominance of these inverse relationships and the demonstration in a minority of studies of other directions of the relationships could not generally be explained by differences between studies in the sex, age, or current size of the subjects. However, the relationship of birth weight with insulin secretion was inconsistent in studies of adults.

CONCLUSIONS

The published literature shows that, generally, people who were light at birth have an adverse profile of later glucose and insulin metabolism. This is related to higher insulin resistance, but the relationship to insulin secretion in adults is less clear.

Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome is a heterogeneous clinical syndrome, which has been defined as the association of hyperandrogenism with chronic anovulation in women without specific adrenal and pituitary gland disease. A family history of polycystic ovary syndrome may be present in a subset of patients; however, the genetic basis of the syndrome remains unclear. Most often, the age of onset is perimenarchal and it is characterized by the appearance of menstrual disturbances, hirsutism, acne, and more rarely, a male pattern of alopecia. In some cases, premature adrenarche may present as a precursor to the development of the syndrome. Polycystic ovary syndrome is also associated with metabolic disturbances, such as obesity and insulin resistance with hyperinsulinemia, for which the pathophysiological role in the development of the syndrome has been recognized. The therapeutic approaches to polycystic ovary syndrome include lifestyle modifications, dietary-induced weight loss, insulin-sensitizing agents, antiandrogens, and oral contraceptives. These treatments may improve the clinical manifestations of excess androgen production and normalize menses in many adolescents and young women with polycystic ovary syndrome. Early recognition of the syndrome and thus, early treatment, may prevent and possibly ameliorate all the symptoms and the potential later development of metabolic and cardiovascular complications.

Endocrine consequences of premature pubarche in post-pubertal Caucasian girls

BACKGROUND

It has been postulated that intrauterine undernutrition may predispose to serious endocrine consequences, including precocious pubarche (PP), functional ovarian hyperandrogenism and insulin resistance syndrome.

OBJECTIVE

The aim of this study was to determine whether a history of PP was associated with the development of hyperandrogenism and/or metabolic consequences and to evaluate the effect of birth weight on this association.

PATIENTS

The study population comprised 27 Caucasian girls with a history of PP and 25 healthy girls of similar age (17.4 +/- 1.3 vs. 17.7 +/- 0.9 years).

RESULTS

Gynecological age, irregular menses and oral contraceptive use were similar in the two groups. PP girls showed an increased Ferriman-Gallway Score [median (range) 8 (4-17) vs. 6 (2-10), P = 0.02] and tended to have more previous history of acne. No statistical differences were found between the groups for mean testosterone (1.7 +/- 0.7 vs. 1.4 +/- 0.7 nmol/l, P = 0.49) and dehydroepiandrosterone sulphate concentrations (7.2 +/- 3.7 vs. 5.8 +/- 2.0 micromol/l, P = 0.15), but mean Delta4-androstenedione concentrations (7.3 +/- 2.4 vs. 4.9 +/- 2.1 nmol/l, P = 0.007) and free androgen index (8.5 +/- 9.7 vs. 3.6 +/- 3.9 IU, P = 0.003) were significantly increased in the PP group. All girls showed normal glucose tolerance with an oral glucose tolerance test. Derived insulin resistance parameters were not statistically different between the two groups and fasting lipids were comparable in both groups. There was no significant effect of birth weight on androgen levels in the PP girls. Moreover, none of the PP girls demonstrated the above-described association.

CONCLUSIONS

Precocious pubarche could be the first sign of future functional ovarian hyperandrogenism but a link between this condition and intrauterine undernutrition or insulin resistance could not be demonstrated in this study.

Timing of puberty and fetal growth

Children born small for gestational age (SGA: birth weight or birth length more than 2 standard deviations below the mean score) are at a higher risk of perinatal morbidity and mortality and of a number of chronic diseases in later life such as hypertension, decreased insulin sensitivity, diabetes mellitus type 2 and an increased risk of cardiovascular disease. The programming of the endocrine axes occurs during critical phases of fetal development and might thus be affected by intrauterine growth retardation. Studies in Northern Spanish adolescent girls have indicated associations between reduced fetal growth and the occurrence of precocious adrenarche, pubarche, hyperandrogenism, polycystic ovary syndrome (PCOS) and hyperinsulinism. These findings have attracted much attention because it might have serious consequences in later life. However, hyperandrogenism and precocious pubarche were not confirmed in a large Dutch study in short children born SGA. Two studies reported a lower number of follicles in the ovaries in girls born SGA, which might have an impact on fertility. Clearly, further studies are required before definite conclusions can be drawn. There are still only limited data concerning the timing of puberty in children born SGA. Most studies indicate that these children start their puberty at a normal age but relatively early within the normal range. Age at menarche seems comparable with controls. Data on duration of puberty, influence of puberty on attainment of adult height, peak height velocity during puberty and fertility are not yet known.

The effect of in-utero undernutrition on the insulin resistance syndrome

The metabolic and cardiovascular complications associated with in-utero undernutrition have been identified during the past 10 years. Reduced fetal growth is independently associated with an increased risk for the development of cardiovascular diseases, the insulin resistance syndrome and its components: hypertension, dyslipidemia, impaired glucose tolerance, and type 2 diabetes. All appear to result from the initial development of insulin resistance that seems to be a key component underlying this association. Several hypotheses have been proposed over the past 10 years to understand this unexpected association. Each of them points to either a detrimental fetal environment or genetic susceptibilities or interactions between these two components as playing a critical role in this context. The hypothesis that this association could be the consequence of genetic/environmental interactions remains at the moment the most attractive. Although the mechanism remains unclear, there is also some evidence that adipose tissue plays a role in the emergence of insulin resistance associated with in-utero undernutrition.