Male Sexual Maturation Research Articles

A time-course study of long term over-expression of ARR19 in mice.

A leucine-rich protein, ARR19 (androgen receptor corepressor-19 kDa), is highly expressed in male reproductive organs and moderately in others. Previously, we have reported that ARR19 is differentially expressed in adult Leydig cells during the testis development and inhibits steroidogenesis by reducing the expression of steroidogenic enzymes. Whereas in prostate, ARR19 represses the transcriptional activity of AR (androgen receptor), it is important for male sexual differentiation and maturation in prostate and epididymis, through the recruitment of HDAC4. In this study we show that long term adenovirus mediated overexpression of ARR19 in mice testis has the potential of inhibiting the differentiation of testicular and prostatic cells by reducing the size of testis and prostate but has no effect on the growth of seminal vesicles. Further, it reduces the level of progesterone and testosterone by reducing the steroidogenic enzymes such as 3HSD, P450c17 and StAR. This is the first study reporting a time-course analysis of the implications of long term overexpression of ARR19 in mice testis and its effect on other organs such as prostate and seminal vesicles. Taken together, these results suggest that ARR19 may play an important role in the differentiation of male reproductive organs such as testis and prostate.

Gonad development and reproduction of the ballyhoo half beak, Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil.

The gonad development and reproductive aspects of Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil were verified. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonad development, reproductive period and fecundity of H. brasiliensis. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. brasiliensis showed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species is 1153 (± 258.22) oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate that H. brasiliensis is a multiple spawner, with active reproductive period during the months of January to June and October. The reproductive period of this species is independent of the rainy period of the region.

Life history traits and implications for conservation of rock carp Procypris rabaudi Tchang, an endemic fish in the upper Yangtze River, China

Rock carp is an endemic fish in the upper Yangtze River basin. Its populations have dramatically declined in the recent years due to human activities, such as overfishing and damming. In the present study, with the aim to give suggestions for better conservation, we investigated age, growth, and reproductive biology of the rock carp using samples collected between 2007 and 2013 from the Chishui River. The results indicate that there are no significant differences between the length–weight relationships of females and males (W = 0.015SL3.155). The von Bertalanffy growth curves computed by the observed length-at-age data could be expressed as Lt = 64.9(1 − e−0.101(t+0.217)). The estimated length at 50 % sexual maturity for males is 24.2 cm (approximately aged 4) and 37.0 cm for females. Female gonad analysis suggests that rock carp is a batch spawner, which can spawn at least twice during the reproductive season, from April to August. Standard length and age of 86.5 % individuals were below 25 cm and 4 years, respectively, indicating that the exploitation is too intensive and that populations are undergoing miniaturization. These data corroborate that a combination of natural and anthropogenic factors has caused a sharp decline in wild populations during recent years, calling for immediate design and implementation of conservation measures for this species.

First Documentation of Male Sexual Maturation in Captivity of Pacific Goliath Grouper, Epinephelus quinquefasciatus

This is the first documentation of male sexual maturation in captivity of Pacific goliath grouper. Males weighed between 15.3 and 16.6 kg and measured 93.5 and 97 cm in total length. No mature females were found during the same 4-year period of observation in captivity.

Evidence that progestins play an important role in spermiation and pheromone production in male sea lamprey (Petromyzon marinus)

Progestins (progestogens, C21 steroids) have been shown to regulate key physiological activities for reproduction in both sexes in all classes of vertebrates except for Agnathans. Progesterone (P) and 15α-hydroxyprogesterone (15α-P) have been detected in sea lamprey (Petromyzon marinus) plasma, but the expression patterns and functions of putative progestin receptor genes have not yet been investigated. The first objective of this study was to determine the differences in mRNA expression levels of nuclear progestin receptor (nPR) and the membrane receptor adaptor protein ‘progesterone receptor membrane component 1’ (pgrmc1) in putative target tissues in males at different life stages, with and without lamprey GnRH-I and -III treatment. The second objective was to demonstrate the function of progestins by implanting prespermiating males (PSM) with time-release pellets of P and measuring the latency to the onset of spermiation and plasma concentrations of sex pheromones and steroids. The third objective was to measure the binding affinity of P in the nuclear and membrane fractions of the target tissues. Expression levels of nPR and pgrmc1 differed between life stages and tissues, and in some cases were differentially responsive to lamprey GnRH-I and -III. Increases in nPR and pgrmc1 gene expressions were correlated to the late stages of sexual maturation in males. The highest expression levels of these genes were found in the liver and gill of spermiating males. These organs are, respectively, the site of production and release of the sex pheromone 3 keto-petromyzonol sulfate (3kPZS). The hypothesis that pheromone production may be under hormonal control was tested in vivo by implanting PSM with time-release pellets of P. Concentrations of 3kPZS in plasma after 1week were 50-fold higher than in controls or in males that had been implanted with androstenedione, supporting the hypothesis that P is responsible for regulating the production of the sex pheromone. P treatment also accelerated the onset of spermiation. Saturation and Scatchard analyses of the target tissues showed that both nuclear and membrane fractions bound P with high affinity and low capacity (KD 0.53pmol/g testis and 0.22pmol/g testis, and Bmax 1.8 and 5.7nM, respectively), similar to the characteristics of nPR and mPR in other fish. The fact that a high proportion of P was also converted in vivo to 15α-P means that it is not yet possible to determine which of these two steroids is the natural ligand in the sea lamprey.

Importance of reproductive biology of a harvest lizard, Tupinambis merianae, for the management of commercial harvesting

Context Management of the exploitation of resources requires biological information on exploited species. The skins of large reptiles have a commercial value as luxury leather items and Tupinambis lizards from southern South America have historically been exploited for this purpose. Argentina implemented management plans for Tupinambis lizards since 1988 that established a minimum capture size based on the width of dried skins, but this prescription has not been linked to local reproductive attributes of species. Aim In this study, we aim to determine the reproductive parameters of Tupinambis merianae and evaluate which class sizes of individuals are susceptible to commercial trade in central Argentina to generate local and species-specific information to improve available management tools. Methods We determined the relationship between the width of dried skins and live body sizes. We identified size at sexual maturity in males and females. Moreover, we determined status of reproductive individuals by body size and characterised gonadal development and seasonal reproductive events in central Argentina. We evaluated the relationship between female body size and clutch size. Key results Reproduction of T. merianae in central Argentina is markedly seasonal, with both sexes concentrating their reproductive activities between October and December. Size at sexual maturity was smaller for males than females, and the percentage of reproductive females was lower than males. In both sexes, the frequency of reproductive individuals was low in smaller lizards, and bigger females had bigger clutch size. The width of dried skins was positively related to body size. Conclusions Size at sexual maturity, and reproductive period, should be taken into account when management plans are designed to minimise any negative impacts of harvesting. Implications In central Argentina, the breeding season coincides with hunting periods set by national legislation. The results of our study have prompted local authorities to impose hunting closures for part of December and to raise the minimum catch size. Further, we offer an equation that can be used as a monitoring tool for estimating snout to vent length of live animals from skins. Studies like ours should be replicated in different areas and extrapolated to other models.

Sex-structure, depth distribution, intermoult period and reproductive pattern of the deep-sea red crab Chaceon affinis (Brachyura, Geryonidae) in two populations in the north-eastern Atlantic

This work investigated the biology of Chaceon affinis in two isolated populations of the Atlantic Ocean, including depth distribution, sexual structure, reproductive patterns and intermoult period. Males were larger and heavier than females. Mean size decreased with depth for both males and females. The highest abundance was found at 600–799m of depth for males and at 800–999m depth stratum for females. The highest abundance of ovigerous females was found at the 800–999m depth stratum. Of the different ovaries’ colour or colour shades recorded, only six categories were histologically characterized. The presence of spermatophores in the spermatheca of females in carapace stages II and III suggests that spermatophores are viable and used during the intermoult period. The size at sexual maturity in females was estimated at 104.4–104.7mm carapace width (CW) in Madeira, and 109.3–110.5mm CW in the Canary Islands. Only three categories of testes were identified. Mature testes consisted in a large mass, with highly coiled vasa deferentia visible to the naked eye. The size at sexual maturity in males was estimated at 113.8mm CW in Madeira and 118.9mm CW in the Canaries. The relative growth of males showed significant changes along the ontogeny and size at which allometric growth changes, as an indicator of morphometric maturity, occurred between 103.2 and 103.6mm CW in Madeira and between 111.4 and 113.1mm CW in the Canaries. In females, size at which allometric growth changes was found for maximum width of fifth abdominal somite (AS5W) at 98.2mm CW in Madeira and 103.0mm CW in the Canaries. The size at maturity obtained for C. affinis indicates that the minimum landing size (MLS) should not be set smaller than 125mm CW in Madeira and 130mm CW in the Canaries. This conservative MLS, higher than length at functional maturity, would safeguard immature individuals until they reach the size at which they can contribute to the reproductive capacity of the population. Ovigerous females were observed from October to April in Madeira, and in all months in the Canaries. Moreover, the observation of berried females in the last developmental stage in all quarters of the year suggests that gonad maturation and release of larvae are asynchronous throughout the spawning season. A total of 138 crabs with CW between 96 and 154mm were tagged off Madeira. Of these, nine were recovered in the same area, more than 900 days after tagging. Eight of the recaptures were females with a wide range of CW confirming intermoult periods exceeding three years with expected growth per moult of less than 20mm CW.

The female reproductive cycle of the neotropical snake Atractus pantostictus (Fernandes and Puorto, 1993) from south-eastern Brazil.

Data on reproductive activity of fossorial species are limited because the specimens are difficult to be observed and captured. Here in, we present the reproductive cycle of female Atractus pantostictus, a fossorial neotropical species, and the sexual maturity of males and females in south-eastern Brazil. The female reproductive cycle of A.pantostictus is seasonal, with vitellogenic follicles being found from September to April and eggs in November, February, March and April with the number varying between two and four. Spermatozoa were found in the lumen of the glandular and non-glandular uterus in females collected during the rainy season. Sperm storage tubules were found in the posterior infundibulum of the females, where the storage of sperm occurs for a short time. The storage may occur because mating and ovulation are dissociated.

Sexual maturation in common vole (Microtus arvalis) males raised under laboratory conditions.

The common vole is one ofthe most numerous rodents in Europe and Asia but its reproductive biology is not fully described. It is thought that females reach reproductive abilities at a very young age, however, there is no data concerning male sexual maturation. The aim of the present study was to determine the rate of sexual maturation of males of the common vole. Research was carried out on 4, 6, 8 and 10 week-old animals. Body, testes and accessory sex glands weights were compared to evaluate morphological development. Epididymal sperm quality was assessed by a motility test, sperm tail membrane integrity, viability, maturity and sperm head morphology. Moreover, the number of sperm cells in 1 mm3 of semen was evaluated. The largest body weights were observed in 8 and 10 week-old males, which also possessed the highest relative weights of gonads and accessory sex glands. These groups of males produce about 2 times more gametes than 6 week-old individuals. The highest seamen quality was noted in 8 and 10 week-old males. Based on the obtained results, it is concluded that among the investigated age groups the most appropriate male age for fertile copulation is between 8 and 10 weeks.

Genome-wide association study of sexual maturation in males and females highlights a role for body mass and menarche loci in male puberty.

Little is known about genes regulating male puberty. Further, while many identified pubertal timing variants associate with age at menarche, a late manifestation of puberty, and body mass, little is known about these variants' relationship to pubertal initiation or tempo. To address these questions, we performed genome-wide association meta-analysis in over 11 000 European samples with data on early pubertal traits, male genital and female breast development, measured by the Tanner scale. We report the first genome-wide significant locus for male sexual development upstream of myocardin-like 2 (MKL2) (P = 8.9 × 10(-9)), a menarche locus tagging a developmental pathway linking earlier puberty with reduced pubertal growth (P = 4.6 × 10(-5)) and short adult stature (p = 7.5 × 10(-6)) in both males and females. Furthermore, our results indicate that a proportion of menarche loci are important for pubertal initiation in both sexes. Consistent with epidemiological correlations between increased prepubertal body mass and earlier pubertal timing in girls, body mass index (BMI)-increasing alleles correlated with earlier breast development. In boys, some BMI-increasing alleles associated with earlier, and others with delayed, sexual development; these genetic results mimic the controversy in epidemiological studies, some of which show opposing correlations between prepubertal BMI and male puberty. Our results contribute to our understanding of the pubertal initiation program in both sexes and indicate that although mechanisms regulating pubertal onset in males and females may largely be shared, the relationship between body mass and pubertal timing in boys may be complex and requires further genetic studies.

Temporal dynamics of reproduction in Hemiramphus brasiliensis (Osteichthyes: Hemiramphidae).

The reproductive aspects of Hemiramphus brasiliensis were analyzed with a view to verify the temporal dynamics of reproduction. This paper presents data on sex ratio, length at first sexual maturity, macroscopic and histological aspects of gonad development, gonadosomatic index (GSI), reproductive period, and fecundity of H. brasiliensis. The fishes were captured from the coastal waters of Rio Grande do Norte, northeastern Brazil. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. brasiliensis showed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species was 1153 (±258.22) mature oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate that H. brasiliensis is a multiple spawner, presenting a prolonged reproductive period during the whole year, with a peak in the month of April, and is considered as an opportunistic strategist.

Effects of male sexual maturity of reproductive endpoints relevant to DART studies in Wistar Hannover rats

Wistar Hannover rats have been utilized as one of major strains in regulatory toxicology studies. This study was performed to verify the appropriate age of male sexual maturity in the development and reproductive toxicity (DART) study in Wistar Hannover rats (RccHan:WIST) by comparing reproductive endpoints between 8, 10 and 12 weeks of ages. Although fertility showed a tendency toward decrease in 8-week-old males, copulation index was not different among three ages. Testis weights reached a plateau at 10 weeks of age, whereas weights of other reproductive organs developed until 12 weeks of age. Indices of spermatogenesis (sperm motility, number of sperm in the epididymis and testis and contents of morphologically abnormal sperm) showed age-related progress and did not fully develop except for 12-week-old. For histology, epididymal tubules in 8-week-old animals showed immaturity with tall epithelium. At cesarean section, dams mated with 8-week-old males showed high incidence of preimplantation loss and the number of live fetuses was less than 10. In conclusion, although reproductive performance attained maturity by age of 10 weeks, spermatogenesis was not fully established at 10-week-old, which could result in a low fertility index. Therefore, we recommend that Wistar Hannover male rats at 12-week-old or older are used to conduct DART study properly and evaluate any adverse effects on dams and embryo-fetal development.

Gene Amplification and Functional Diversification of Melanocortin 4 Receptor at an Extremely Polymorphic Locus Controlling Sexual Maturation in the Platyfish

In two swordtail species of the genus Xiphophorus, the onset of puberty has been shown to be modulated at the P locus by sequence polymorphism and gene copy-number variation affecting the type 4 melanocortin hormone receptor Mc4r. The system works through the interaction of two allelic types, one encoding wild type and the other dominant-negative receptors. We have analyzed the structure and evolution of the P locus in the platyfish Xiphophorus maculatus, where as many as nine alleles of P determining the onset of sexual maturity in males and females, fecundity in females, and adult size in males are located on both the X and Y chromosomes in a region linked to the master sex-determining locus. In this species, mc4r has been amplified to up to 10 copies on both the X and Y chromosomes through recent large serial duplications. Subsequently, mc4r paralogues have diverged considerably into many different subtypes. Certain copies have acquired new untranslated regions through genomic rearrangements, and transposable element insertions and other mutations have accumulated in promoter regions, possibly explaining observed deviations from the classical mc4r transcriptional pattern. In the mc4r-coding sequence, in-frame insertions and deletions as well as nonsense and missense mutations have generated a high diversity of Mc4r-predicted proteins. Most of these variants are expressed in embryos, adults, and/or tumors. Functional receptor characterization demonstrated major divergence in pharmacological behavior for Mc4r receptors encoded by different copies of platyfish mc4r, with differences in constitutive activity as well as binding and stimulation by hormones. The high degree of allelic and copy-number variation observed between individuals can explain the high level of polymorphism for sexual maturation, fecundity, and body size in the platyfish: multiple combinations of Mc4r variants with different biochemical properties might interact to modulate the melanocortin signaling that regulates the hypothalamus-pituitary-gonadal axis.

Carbamazepine-exposure during gestation and lactation affects pubertal onset and spermatic parameters in male pubertal offspring

Carbamazepine (CBZ) is an anti-epileptic drug that acts on Leydig cells, affecting steroidogenesis and causes fetal malformation. The aim of this study was to investigate the effects of CBZ on male sexual maturation and other male parameters. Rat dams were treated with CBZ during pregnancy and breastfeeding. The anogenital distance (AGD) and the anogenital index (AGI) were obtained. Testicular descent and preputial separation were also evaluated. The offspring was euthanized at PND 41 and 63. The accessory glands were weighed and the testes were collected for histopathological, morphometric and sterological analyses. The numerical density of Leydig cells and hormone dosage were obtained. CBZ caused an increase of AGI and a delay of testicular descent and of preputial separation. CBZ also caused a decrease of testosterone level and of sperm count and an increase of abnormal sperm. These results indicate that CBZ delays puberty onset and affects steroidogenesis and sperm quality.

Analysis of the genitalia rotation in the male Anopheles funestus (Diptera: Culicidae)

Anopheles funestus is a major malaria vector in Africa. Insecticide resistance has developed in populations of this species in several African countries, prompting the need to develop additional vector control methods such as the sterile insect technique (SIT). This technique requires an understanding of those underlying physiological events that lead to sexual maturity of An. funestus males, the rotation of their genitalia in particular. The aim of this study was to qualitatively and quantitatively describe genital rotation in An. funestus males as it is an essential function of sexual maturation. Genital rotation of all the males reached its final rotation stage (135–180° rotation) 36h post emergence at 23±1°C in laboratory colonised An. funestus males. These males had a comparable rotation rate to wild caught An. funestus at the same temperature setting. A temperature change (either 18±1°C or 29±1°C versus 23±1°C) significantly influenced the genital rotation rate such that this rate increased with increasing temperature. This information enhances our knowledge of the An. funestus male biology. This is important in terms of applying the sterile insect technique as the understanding and manipulation of the rate of sexual maturation in males has implications for the timing of sterile male release.

Quantitative trait loci for precocious parr maturation, early smoltification, and adult maturation in double-backcrossed trans-Atlantic salmon (Salmo salar)

Quantitative trait loci (QTL) for age at smoltification and adult maturation have been mapped in several salmonid species but less is known about precocious male parr maturity. Phenotypic information on length at age, precocious male parr maturation (paedogenesis), early smoltification, and adult sexual maturation was recorded for four double-backcross families of F1 European/North American trans-Atlantic salmon that had been genotyped for 320 (family A) or 121 (families B, C and D) single nucleotide polymorphisms (SNPs). The locations of QTL for early smoltification and for precocious parr and adult maturation in Atlantic salmon (Salmo salar) were identified and then compared with QTL in homologous chromosomal arms of rainbow trout (Oncorhynchus mykiss). Novel QTL for precocious male parr maturation on Ssa05, Ssa07, Ssa09, Ssa10, Ssa12, Ssa16 and Ssa20 were significant at the genome-wide level as were QTL for early smolting detected on chromosomes Ssa05, Ssa08, Ssa13, and Ssa23. As predicted, precocious male parr were significantly less likely to become early smolts. Two QTL for adult sexual maturation on chromosomes Ssa21 and Ssa23 were significant at the chromosome-wide level as were QTL for adult length on Ssa05 and Ssa24. Separate analysis of family A resulted in novel QTL being detected on Ssa01q for early smolting, Ssa17 and Ssa22 for precocious maturation, and on Ssa03 and Ssa20 for length at the early smolt measuring period. The two chromosomes (Ssa21 and Ssa23) that contained QTL for adult maturation were homologous to two chromosomes (Omy22 and Omy4) that contain QTL for adult maturation in rainbow trout.

Evidence for multiple sex-determining loci in Tasmanian Atlantic salmon (Salmo salar)

Phenotypic sex in salmonids is determined primarily by a genetic male heterogametic system; yet, sex reversal can be accomplished via hormonal treatment. In Tasmanian Atlantic salmon aquaculture, to overcome problems associated with early sexual maturation in males, sex-reversed females are crossed with normal females to produce all female stock. However, phenotypic distinction of sex-reversed females (neo-males) from true males is problematic. We set out to identify genetic markers that could make this distinction. Microsatellite markers from chromosome 2 (Ssa02), to which the sex-determining locus (SEX) has been mapped in two Scottish Atlantic salmon families, did not predict sex in a pilot study of seven families. A TaqMan 64 SNP genome-wide scan suggested SEX was on Ssa06 in these families, and this was confirmed by microsatellite markers. A survey of 58 families in total representing 38 male lineages in the SALTAS breeding program found that 34 of the families had SEX on Ssa02, in 22 of the families SEX was on Ssa06, and two of the families had a third SEX locus, on Ssa03. A PCR test using primers designed from the recently published sdY gene is consistent with Tasmanian Atlantic salmon having a single sex-determining gene that may be located on at least three linkage groups.

Onset of sexual maturity and relative growth of the freshwater crab Trichodactylus fluviatilis (Trichodactyloidea) in south-eastern Brazil

The main purpose of this study was to provide an estimate for the onset of morphological sexual maturity in the freshwater crab Trichodactylus fluviatilis, from a population located in south-eastern Brazil, based on the relative growth relationships, as well as the characterization of “handedness”. Monthly collections were carried out at night, from January 2006 to January 2007, in a small water body. In the laboratory, the crabs were sexed; the following body structures were measured and the estimate of onset of sexual maturity was given by the logistic function, as y = a/(1 + be − cx ), for 50% of the population to reach the adult phase (CW50carapace width). Right propodus length and abdomen width were the best-fit relationships to represent the onset of sexual maturity for males and females, respectively. Based on the logistic function, the onset of sexual maturity was estimated to occur at around 18 mm CW for both sexes. The relative growth recorded for this species is consistent with the model for brachyuran crabs (Hartnoll RG. 1982, Growth. In: Bliss, DE, editor. The biology of Crustacea: embryology, morphology and genetics. New York: Academic Press. p. 111–196), except for the abdomen growth, which is likely to be an adaptive condition related to protection of the newly hatched young.

Social interaction facilitates reproduction in male German cockroaches, Blattella germanica

Sociality can be beneficial for individuals because it may increase access to resources, provide greater protection from predators and create opportunities for mating. In some species, social conditions and experience also influence the physiology and behavioural responses of individuals. Although social facilitation of sexual maturation is poorly understood in insects, the German cockroach has served as an important model system for this phenomenon as group-housed females mature faster than solitary females. However, social modulation of male reproduction has not been investigated in this or any other nonpolyphenic insect species. We investigated the relative effects of social interactions and isolation on endocrine, reproductive and behavioural events during sexual maturation of B. germanica males. Results show that social interactions significantly facilitate juvenile hormone biosynthesis as well as protein production by the accessory reproductive glands, whereas isolation suppresses these processes. Other processes, such as accumulation of cuticular hydrocarbons, maturation of the male's courtship readiness and his readiness to copulate, appear to be relatively independent of social experience. However, both courtship and copulation latencies declined with age more in socially paired males than in isolated males. Our study is the first to reveal that social interactions have a profound effect on certain aspects of male reproductive physiology and behaviour in an insect species that does not exhibit phase or developmental polyphenism . • Social interactions affect male cockroach reproductive physiology and behaviour. • Group living facilitates juvenile hormone biosynthesis in adult males. • Group living facilitates protein production in adult male accessory reproductive glands. • Social conditions influence male sexual maturation. • Some events during sexual maturation are independent of male social experience.

Using non-invasive methods to characterize gonadal hormonal patterns of southern three-banded armadillos (Tolypeutes matacus) housed in North American zoos

Understanding the basic reproductive biology and limitations to successful breeding of the southern three-banded armadillo (Tolypeutes matacus) is necessary to maintain viable zoo populations. Our objectives were to: 1) describe the reproductive biology using non-invasive, fecal hormone analysis; 2) assess influence of season on gonadal hormonal patterns in both the sexes; 3) characterize reproductive cyclicity and pregnancy in the female; and 4) characterize the onset of sexual maturity in males. Nineteen armadillos were monitored including: 13 (7 males, 6 females) from Lincoln Park Zoo and six (3 males, 3 females) from San Antonio Zoological Garden. Fecal samples (n=5220; 275/animal/yr) were collected 5 to 7 times a week for 1 year. Hormones were extracted from feces and analyzed for progestagen (females) and androgen (males) metabolite concentrations using enzyme immunoassays. Mean estrous cycle length (26.4±1.3 days) did not vary (P<0.05) among individuals (n=9). Mean gestation length (n=3) was 114.0±0.6 days long with mean fecal progestagen metabolites increasing 10-fold during pregnancy. Seasons did not influence (P<0.05) fecal androgen or progestagen metabolites. These data can assist with management decisions, which will directly affect the success of this species in zoos.