Female Puberty Research Articles

Endocrinology of female puberty.

Puberty is the developmental process that culminates in reproductive capability. It is initiated by the release of gonadotropin-releasing hormone from specialized neurons of the hypothalamus to stimulate hormonal cascades and gonadal activation. The age of pubertal onset in girls may be younger than in previous decades, emphasizing the gaps in knowledge about pubertal onset and factors that modulate it. This review describes the state of the debate on the age of pubertal initiation, recent insights into the physiology of female puberty and its relationship to childhood obesity, and the regulation of gonadotropin-releasing hormone neurons at puberty. Recent studies suggest that the average age of pubertal onset is decreasing in American girls, sparking controversy in defining the age at which puberty is considered precocious. Obese girls have hyperinsulinemia and hyperandrogenemia prepubertally, but it is unclear whether these factors play a role in the early onset of puberty in obese girls. The kisspeptin/G protein-coupled receptor 54 pathway is important for pubertal initiation; an activating mutation in the pathway has been associated with precocious puberty. The recent trend toward obesity has been proposed to play a role in the cause of early puberty in girls. The molecular mechanisms that initiate puberty are slowly being elucidated, with the discovery of kisspeptin prompting a novel direction in reproductive research.

A Study of Voice Changes in Various Phases of Menstrual Cycle and in Postmenopausal Women

Larynx is responsible for the generation of voice and subsequently impacts on communication, social interaction, personality, and artistic expression. The vocal instrument is comprised of the vibratory body, the respiratory power source, and the oropharyngeal resonating chamber. The lungs are the power supply, the larynx is the vibratory source, and the supraglottal vocal tract (supraglottal pharynx oral cavity, nasal cavity) is the resonator that shapes the sound into words and songs. During the phase of expiration as the diaphragm relaxes and the chest wall recoils, air is pushed through the nearly closed vocal folds. The aerodynamic forces of the air column and myoelastic properties of the vocal folds are responsible for the repeated opening and closing of the glottal tissue that pulses that air column as it flows out. These disruptions in the steady state of tracheal air pressure by glottal activity and vocal fold vibrations result in voice production. Voice is characterized by its frequency intensity and harmonics. The harmonics are hormonally dependent. This is illustrated by changes that occur during male and female puberty. The female voice evolves from childhood to menopause under the varied influences of estrogen, progesterone, and testosterone. These hormones are the dominant factor in determining voice changes throughout life. Female voice has a fundamental frequency one-third lower than that of a child. In males, androgen released at puberty is responsible for the male vocal frequency being an octave lower than that of a child. The females have a reproductive system, which undergoes a regular cyclic change known as the menstrual cycle. Laryngeal changes are evident and fluctuate systematically during the reproductive years with the menstrual cycle. The main objective of this experiment is to provide a solid ground with evidence of changes in voice because of sexual hormones, which will form the base of a multidisciplinary approach to a comprehensive and integrated understanding of premenstrual and menopausal female voice.

FXYD1, a Modulator of Na+,K+‐ATPase Activity, Facilitates Female Sexual Development by Maintaining Gonadotrophin‐Releasing Hormone Neuronal Excitability

The excitatory tone to gonadotrophin-releasing hormone (GnRH) neurones is a critical component underlying the pubertal increase in GnRH secretion. However, the homeostatic mechanisms modulating the response of GnRH neurones to excitatory inputs remain poorly understood. A basic mechanism of neuronal homeostasis is the Na(+),K(+)-ATPase-dependent restoration of Na(+) and K(+) transmembrane gradients after neuronal excitation. This activity is reduced in a mouse model of Rett syndrome (RTT), a neurodevelopmental disorder in which expression of FXYD1, a modulator of Na(+),K(+)-ATPase activity, is increased. We now report that the initiation, but not the completion of puberty, is advanced in girls with RTT, and that, in rodents, FXYD1 may contribute to the neuroendocrine regulation of female puberty by modulating GnRH neuronal excitability. Fxyd1 mRNA abundance reaches maximal levels in the female rat hypothalamus by the fourth postnatal week of life (i.e., around the time when the mode of GnRH secretion acquires an adult pattern of release). Although Fxyd1 mRNA expression is low in the hypothalamus, approximately 50% of GnRH neurones contain Fxyd1 transcripts. Whole-cell patch recording of GnRH-EGFP neurones revealed that the neurones of Fxyd1-null female mice respond to somatic current injections with a lower number of action potentials than wild-type cells. Both the age at vaginal opening and at first oestrous were delayed in Fxyd1(-/-) mice, but adult reproductive capacity was normal. These results suggest that FXYD1 contributes to facilitating the advent of puberty by maintaining GnRH neuronal excitability to incoming transsynaptic stimulatory inputs.

The stimulatory effect of male agouti (Dasyprocta prymnolopha) on the onset of female puberty

The objective of this research was to analyze female agouti puberty. We did not observe the onset of puberty when the females were raised without males. When an adult male was put together with other adults and no cycling females, the onset of estrous cycle was observed after 10 to 60 days. When the young females were raised with a male, the onset of puberty was reached at 9 months. We concluded that the male agouti influences the onset of puberty in females, and that the dominant female, apparently, inhibits or delays the puberty of the other agouti females of the group. We suggest further studies be made concerning the social control of the reproduction of these animal.

Effect of Central Antileptin Antibody on the Onset of Female Rat Puberty

The effect of intracerebroventricular (ICV) antileptin antibody on the onset of puberty in the female rat and the relationship between serum leptin, luteinizing hormone (LH), and body weight were investigated. Antileptin antibody (group A) was infused ICV from days 23–36 in prepubertal female rats whereas the control (group B) received ICV goat immunoglobulin G (IgG). In the antileptin group, mean day of vaginal opening (VO) was postponed (day 34 versus day 30, P < .01 ). Body weight trended higher after 30 days in the antileptin group but not significantly. However, there was no difference in serum leptin and LH between the two groups on the day of VO. Serum leptin was relatively constant from day 23 through day 31 and did not correlate with LH (r = 0.14, P = .10). These studies demonstrate that central leptin promotes the onset of female rat puberty as evidenced by VO. Finally, central leptin impacts female rat pubertal onset in distinction from serum leptin and body weight.

Om klorose og blodfattige jenter på slutten av 1800-tallet

Towards the end of the 1800 s, chlorosis was a frequently used diagnosis, in Norway as well as in America and the rest of Europe. The physiological basis for the disease was assumed to be decreased levels of haemoglobin and/or red blood cells. Chlorosis was not synonymous with anaemia, but rather a subcategory with a vague symptom-based picture associated with female puberty. The different opinions on causes of the disease can be divided into three main groups: environmental, moral and biological-constitutional. At the time, it was well known that iron was an effective treatment. In a cultural critical perspective the disease was seen both as a phenomenon of degeneration and as a reaction to modern life with its stress and demands. During the first decades of the 1900 s, the chlorotic girl disappeared from medical textbooks and articles. The article points at medical, biological and dietary improvements as explanations for why chlorosis disappeared as a diagnosis, but also considers historical aspects such as new cultural norms for femininity, changed laws and an increasing political understanding of health's role in society.

Effect of Central Antileptin Antibody on the Onset of Female Rat Puberty

Effect of Central Antileptin Antibody on the Onset of Female Rat Puberty

Dietary exposure assessment of pregnant women to bisphenol-A from cans and microwave containers in Southern Spain

Bisphenol-A (BPA), material for polycarbonate and epoxy resin synthesis, has been detected in canned food, among other food containers. In mammal studies, BPA transferred from mother to fetus, caused abnormality of reproductive organs, and advanced female puberty. BPA from canned food and microwave containers was analyzed using high performance liquid chromatography and gas chromatography-mass spectrometry. Population was cohort of mother–son pairs established at Granada University Hospital. Frequency of food consumption (including canned food) was studied with a semi-quantitative questionnaire. The most frequently consumed products were fish and juice cans, consumed 1–3 times/week by 34.7% and 22.3% of the study population, respectively. The women made little use of polymer microwave containers, 52.8% never using them and 45.9% using them <3 times/month. Estimated mean (standard deviation) intake of BPA was 1.1(0.839) microgram/day. No relationship was found between BPA exposure and maternal socio-demographic variables or newborn characteristics. This study offers the first estimate of BPA dietary intake by pregnant women in Southern Spain. The consumption of canned foods and drinks by these women means that their exposure was lower than EFSA estimates for the European population. Nevertheless it remains of concern, given the proven undesirable effects of low-level exposure and higher susceptibility of pregnant women.

Relationship of plasma ghrelin and adenohypophyseal hormone levels in female precocious puberty

To investigate the relationship of plasma ghrelin and adenohypophyseal hormone levels in female precocious puberty. A total of 84 patients aged from 6 to 9 years were enrolled in this study. They were divided into idiopathic central precocious puberty (ICPP) and premature thelarche(PT)groups according to their secondary sexual characteristics, bone age, volumes of uterus and ovary, and results of GnRH test. Plasma ghrelin levels were measured by radioimmunoassay. ACTH, TSH, PRL, GH, LH and FSH were measured by chemoluminescence technique. Ghrelin levels in ICPP group were Log (2.42+/-0.26) ng/L, which were significantly lower than those in PT group and controls [Log (2.62+/-0.21) ng/L and Log (2.58+/-0.44) ng/L, respectively, P<0.05]. However there was no significant difference between PT group and controls(P>0.05). Ghrelin levels of ICPP girls with Tanner III were Log (2.31+/-0.24) ng/L, significantly lower than those of ICPP girls with Tanner II [Log (2.53+/-0.24) ng/L, P<0.05]. By bivariate correlation analysis, ghrelin levels in precocious puberty girls were negatively correlated with ACTH, PRL and LH15, LH30 and LH60 in GnRH test(r=-0.248, -0.235, -0.445, 0.405, 0.398, respectively, P<0.05). No significant correlation was found between ghrelin and GH, LH0(-2), FSH0(-2), and FSH15, FSH30 and FSH60 in GnRH test. ICPP girls have lower plasma ghrelin levels, which are decreased with the development of Tanner stage. The plasma ghrelin levels are negatively correlated with ACTH, PRL and LH.

Kinesin Superfamily-Associated Protein 3 Is Preferentially Expressed in Glutamatergic Neurons and Contributes to the Excitatory Control of Female Puberty

It was earlier shown that expression of kinesin superfamily-associated protein 3 (KAP3), involved in the neuronal anterograde, microtubule-dependent transport of membrane organelles, increases in the hypothalamus of female rats during the juvenile phase of sexual development. KAP3 mRNA is abundant in the hypothalamus, suggesting that it might be expressed in broadly disseminated neuronal systems controlling neuroendocrine function. The present study identifies one of these systems and provides evidence for an involvement of KAP3 in the excitatory control of female puberty. In situ hybridization and immunohistofluorescence studies revealed that the KAP3 gene is expressed in glutamatergic neurons but not in GABAergic or GnRH neurons. Hypothalamic KAP3 mRNA levels increase during the juvenile period of female prepubertal development, remaining elevated throughout puberty. These changes appear to be, at least in part, estradiol dependent because ovariectomy decreases and estradiol increases KAP3 mRNA abundance. Lowering hypothalamic KAP3 protein levels via intraventricular administration of an antisense oligodeoxynucleotide resulted in reduced release of both glutamate and GnRH from the median eminence and delayed the onset of puberty. The median eminence content of vesicular glutamate transporter 2, a glutamate neuron-selective synaptic protein, and synaptophysin, a synaptic vesicle marker, were also reduced, suggesting that the loss of KAP3 diminishes the anterograde transport of these proteins. Altogether, these results support the view that decreased KAP3 synthesis diminishes GnRH output and delays female sexual development by compromising hypothalamic release of glutamate.

Serological prevalence of echinococcosis and risk factors for infection among children in rural communities of southern Ningxia, China

To assess the usefulness of serology as an indicator of Echinococcus transmission for developing preventive measures against echinococcosis in rural communities. Cross-sectional survey in 2002 among 861 children aged 7 to 18 years in Xiji County, Ningxia, China. Before ultrasound abdominal examination, a questionnaire was used to identify socioeconomic, sanitary and hygiene risk factors for echinococcal infection; filter paper blood samples were collected from each child for specific antibody detection using EmP (Echinococcus multilocularis) and EgB (Echinococcus granulosus) antigens. Transmission of both E. multilocularis and E. granulosus occur in this area. Serological prevalence was far higher than disease prevalence in this age range. We found no gender-related differences of seroprevalence among the children, suggesting an equal chance of exposure to echinococcal egg-contaminated environments. The seroprevalence distribution was associated with changes in the ecology of wild hosts for E. multilocularis contamination, and with changes in socio-geographic features of the communities for E. granulosus contamination. Serological data obtained for children in mass surveys of echinococcosis appear to be a comprehensive and useful tool to monitor changes of transmission dynamics in humans and provide 'warning signals' to decision makers for the instigation of specific control measures against the disease.

Skeletal maturation in children with cerebral palsy and its relationship with motor functioning

The objective of this study was to describe skeletal maturation in relation to chronological age in children with cerebral palsy (CP) aged 9 to 16 years, and to analyze the relationship between skeletal maturation and motor functioning. The skeletal age of 100 children with CP (37 females, 63 males; age 9, 11, or 13 y; 73 ambulant, 27 non-ambulant) was determined over a period of 3 years based on X-rays of the hand (Greulich and Pyle technique). Motor functioning was measured with the Gross Motor Function Measure-66. The skeletal age of females with CP was significantly higher than their chronological age, but this did not apply to males. Longitudinal analysis showed no difference in the course of skeletal age in relation to chronological age over a 3-year period for sex or for level of ambulation. No association was found between changes in skeletal age and changes in gross motor function over the 3-year period. Skeletal age during (pre-)puberty in females with CP is advanced in relation to chronological age. No evidence was found that children with CP are at risk for deterioration in gross motor function as a result of skeletal maturation during puberty.

The timing of puberty in cultured female yellowtail flounder, Limanda ferruginea (Storer): Oogenesis and sex steroid production in vivo and in vitro

This study examines puberty in female yellowtail flounder, correlating macroscopic, histological and endocrine parameters at the gonadal level. Short-term ovarian tissue incubations were used to study estradiol-17β production in relation to oogenic stage. Examining 2 year classes of young flounder demonstrated that cultured females retain phenotypic plasticity in reproductive age with pubertal onset occurring in one-year, two-year and three-year-olds. Immature ovaries were steroidogenic and capable of responding to gonadotropic stimulation. Endocrine puberty in females was detected by a peak in estradiol-17β production during the cortical alveolar oocyte stage prior to any ovarian evidence of vitellogenesis. Puberty, once initiated, proceeded to ovulation within 8 to 12 months; vitellogenic oocyte development followed the group synchronous pattern. Estradiol-17β was clearly the dominant of the two measured plasma hormones during pubertal onset and throughout vitellogenesis. Plasma testosterone was consistently detectable at low levels by mid-to late-vitellogenesis. Ovaries showed the highest sensitivity to gonadotropic stimulation in vitro during late-vitellogenesis. Variable plasma levels in both estradiol-17β and testosterone occurred in preovulatory and ovulating females during the captive spawning period. Together the results show that yellowtail flounder can mature at a young age and small size when culture conditions permit. In addition, the early sensitivity to gonadotropin by the immature ovaries may be an important physiological determinant for the timing of puberty in this species.

Growth and Reproduction of the Portunid Crab Charybdis Bimaculata (Decapoda: Brachyura) in Tokyo Bay

Abstract The abundance, sex ratio, growth, sexual maturity, morphological sex dimorphism, and reproduction of the portunid crab Charybdis bimaculata was studied in Tokyo Bay, Japan, between November 2002 and October 2003. Relative abundance [inferred from catch-per-unit-effort (CPUE)] was higher and lower during summer and winter months, respectively. The proportion of males varied between 0.2-0.5 throughout the year and the overall sex ratio was greatly biased toward females. The population had a unimodal size frequency distribution and the life-span was estimated to be about one year. Growth was not depressed in winter and was adequately described by the von Bertalanffy growth equation. The puberty molt in males brought about changes in the relative size of the chelipeds and gonopods and was estimated to occur within a carapace length (CL) range of 12.50-16.00 mm. Puberty in females was evidenced by a sharp increase in the pleon width and was estimated to occur at CLs between 11.34 and 16.74 mm. Morphol...

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The reproduction, development and growth of Akodon lindberghi were studied in captivity. The colony was derived from animals captured in Simão Pereira, Minas Gerais state, which represents a new area of geographical distribution known for this species. Twelve males and twelve females were crossed, producing 144 young in 53 litters. Post-partum oestrus was observed and gestation length was estimated in 23 days. Litter size ranged from 1 to 4 with a mean of 2.72 (SD = 0.97, n = 53) and modal size of 3. Sexual dimorphism was neither present in body mass at birth nor at weaning. There was a significant negative correlation between litter size and mass at birth or weaning. Permanent emergence of adult external appearance occurred at 15 days. Puberty for males and females was 43 and 42 days, respectively, and the first fecundation event for two females was recorded at 47 and 54 days of age. The weight growth was described by fitting a Gompertz model. No significant difference was found in any parameter of growth curves for males and females. Measurements (head-body, tail, hind foot and internal and external ear lengths) obtained for adult individuals also did not reveal the presence of sexual dimorphism.

Consequences of in ovo exposure to p, p′-DDE on reproductive development and function in Japanese quail

This study was conduced to assess the effects of a one time embryonic exposure to p, p′-DDE (dichlorodiphenyldichloroethylene; DDE) on the reproductive development and function in Japanese quail ( Coturnix japonica). Embryos were exposed at day one of incubation to either 20 or 40 μg DDE or a sesame oil vehicle control (injection volume = 20 μl). Onset of puberty, gonadal histopathology, sperm motility, cloacal gland size, and male copulatory behavior were assessed in adults. DDE accelerated onset of puberty in females and reduced male reproductive behaviors. Gonadal morphology and sperm motility appeared to be unaffected. Results from this study provide evidence that the neuroendocrine system may be more sensitive and less resilient to embryonic exposure to contaminants than traditional measures of reproductive success following contaminant exposure in adults. This study further supports the inclusion of behavioral assessments in toxicity tests.

Neuroendocrine Effects of Androgens in Adult Polycystic Ovary Syndrome and Female Puberty

In addition to hyperandrogenism and ovulatory dysfunction, polycystic ovary syndrome (PCOS) is characterized by neuroendocrine abnormalities including a persistently rapid gonadotropin-releasing hormone (GnRH) pulse frequency. Rapid GnRH pulsatility favors pituitary secretion of luteinizing hormone (LH) over that of follicle-stimulating hormone (FSH). Excess LH stimulates ovarian androgen production, whereas relative deficits in FSH impair follicular development. The rapid GnRH pulse frequency is a result of reduced progesterone-mediated feedback inhibition of the GnRH pulse generator secondary to infrequent luteal phase increases in progesterone, as well as reduced hypothalamic sensitivity to progesterone feedback. Progesterone sensitivity is restored by treatment with the androgen receptor blocker flutamide. As such, hyperandrogenemia appears to play an important pathophysiologic role in PCOS. Adolescent hyperandrogenemia is believed to be a precursor to adult PCOS. In addition to increased LH concentrations and pulse frequency, some girls with elevated androgen levels also demonstrate reduced hypothalamic sensitivity to progesterone feedback. We hypothesize that excess peripubertal androgens may reduce the sensitivity of the GnRH pulse generator to sex steroid inhibition in susceptible individuals, resulting in increased GnRH pulse frequency and subsequent abnormalities in gonadotropin secretion, ovarian androgen production, and ovulatory function. Over time, these abnormalities may progress to the clinical hyperandrogenism and chronic oligo-ovulation typical of adult PCOS.

Expression of a Tumor-Related Gene Network Increases in the Mammalian Hypothalamus at the Time of Female Puberty

Much has been learned in recent years about the central mechanisms controlling the initiation of mammalian puberty. It is now clear that this process requires the interactive participation of several genes. Using a combination of high throughput, molecular, and bioinformatics strategies, in combination with a system biology approach, we singled out from the hypothalamus of nonhuman primates and rats a group of related genes whose expression increases at the time of female puberty. Although these genes [henceforth termed tumor-related genes (TRGs)] have diverse cellular functions, they share the common feature of having been earlier identified as involved in tumor suppression/tumor formation. A prominent member of this group is KiSS1, a gene recently shown to be essential for the occurrence of puberty. Cis-regulatory analysis revealed the presence of a hierarchically arranged gene set containing five major hubs (CDP/CUTL1, MAF, p53, YY1, and USF2) controlling the network at the transcriptional level. In turn, these hubs are heavily connected to non-TRGs involved in the transcriptional regulation of the pubertal process. TRGs may be expressed in the mammalian hypothalamus as components of a regulatory gene network that facilitates and integrates cellular and cell-cell communication programs required for the acquisition of female reproductive competence.

An androgen-dependent sexual dimorphism visible at puberty in the rat hypothalamus

Morphological studies in rodents have well documented the masculinization of the perinatal brain by estradiol derived from aromatized testosterone, and the resulting irreversible quantitative sex-differences generated in cell numbers or expression of chemical phenotypes. Here, using immunohistochemistry, we explored how this applies to the postnatal development and masculinization of the neurokinin B (NKB)-containing system of the arcuate nucleus/median eminence complex (ARC/ME). In adult rats, NKB-immunoreactive neurons exhibit an unusual, qualitative sexual dimorphism of their ventral axonal projections: to the neuropil in females, to capillary vessels in males. In adults, there was no sex-difference in the numbers of NKB-immunoreactive perikarya or capillary vessels in the ARC/ME, suggesting that this sexual dimorphism cannot be explained by the existence of supernumerary structures. At birth (day 0) the NKB system was immature in both sexes, and while its adult features emerged progressively until puberty in females, they did not develop before puberty (day 40) in males, revealing a sexual dimorphism only late postnatally. When males were orchidectomized at day 30, the masculine distribution of NKB-immunoreactive axons expected at day 40 was not seen, while it was apparent after chronic treatment with testosterone or dihydrotestosterone, suggesting a testicular masculinizing action via androgen receptors at puberty. Moreover in these prepubertal-orchidectomized males, the distribution of NKB-immunoreactive axons was surprisingly feminized by chronic estradiol alone, suggesting that NKB neurons are not irreversibly programmed before puberty. Last, in adult females, the distribution of NKB-immunoreactive axons was feminine 30 days after ovariectomy, and it was masculinized after concurrent chronic dihydrotestosterone, suggesting that NKB neurons remain responsive to androgens late in reproductive life.Thus, the sexual differentiation of the hypothalamus proceeds well beyond the perinatal period and includes the epigenetic action of non-aromatizable androgens upon subsets of neurons that have retained bipotent features.

Highlights in DD

“Highlights” is a feature that calls attention to exciting advances in developmental biology that have recently been reported in Developmental Dynamics. Development is a broad field encompassing many important areas. To reflect this fact, the section will spotlight significant discoveries that occur across the entire spectrum of developmental events and problems: from new experimental approaches, to novel interpretations of results, to noteworthy findings utilizing different developmental organisms. Macrophages and morphology (Dev Dyn 235:3222–3229). If you think that macrophages are just gluttons that gobble up cellular debris and foreign material, think again. According to Pollard's group, macrophages also shape mammary gland branching morphology. During female puberty, rudimentary ducts in mammary glands start to grow. At the leading edge of growing ducts are epithelial structures called terminal end buds (TEBs), whose surrounding stromal layer is collagen-rich. Here, the authors show that mice deficient in macrophages have abnormal TEB morphology, but its total amount of collagen I is unchanged. This finding demonstrates that macrophages regulate TEB morphology, but not by producing monomeric collagen. The fascinating observation that macrophages travel along the TEB collagen matrix in vivo agrees with their conclusion that macrophages instead promote the organization of collagen into fibrillar bundles. It takes guts (Dev Dyn 235:3259–3267). Sea cucumbers (Holothuria glaberrima) eject their intestines to distract or repel predators. Before you get any ideas, be advised that while they have the remarkable capacity to regenerate their internal organs, humans do not. In documenting intestine regeneration, this study focuses on a population of sphere-shaped, vesicle-filled cells called spherulocytes. With the help of spherulocyte-specific antibodies, the authors track the cells during the regeneration process. Found in connective tissue throughout the organism, spherulocytes increase in number, change morphology, appear to fuse with intestinal extracellular matrix, and dispel their vesicular contents. These data are highly suggestive that spherulocytes participate in regeneration and/or wound healing. Identifying the vesicular contents may be key to understanding exactly what these mysterious cells do. Sugar coated fish (Dev Dyn 235:3423–3431, 3432–3437). In back-to-back papers, Cadwallader and Yost present compelling evidence that sugar does not deserve such a bad rap. Heparin sulfate (HS) proteoglycans bind to extracellular molecules, modulating several biological processes, including cell adhesion and cell signaling. HS ligand binding specificity is influenced by O-sulfotransferases (OSTs), which position sulfates on HS sugar chains. Here, the authors detail the zebrafish developmental expression patterns of two OST families, 3- and 6-OSTs, most members of which are conserved in humans. Interestingly, they find that the enzymes show unique tissue distribution patterns, suggesting that each plays a specialized role in development.