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PubMed1981

Influence of prepubertal consumption of zearalenone on sexual development of boars.

Littermate pairs of crossbred boars were fed 40 ppm zearalenone from 14 to 18 weeks of age, and the effects on reproductive development were examined. Compared to controls, boars fed zearalenone subsequently had reduced libido scores (P greater than.05), and fewer treated animals exhibited mating behavior. Plasma concentrations of testosterone were depressed (P greater than .05) during consumption of zearalenone. Zearalenone did not significantly affect age at which sperm were first voided in the urine (P greater than .25). Body weight and testicular size were not affected by zearalenone. At 36 weeks of age, testicular weight, epididymal weight, spermatid numbers, motility of cauda epididymal sperm and testicular morphology did not differ between control boars and those that had consumed zearalenone.

Androstenedione↗
PubMed1995

Schizosaccharomyces pombe atf1+ encodes a transcription factor required for sexual development and entry into stationary phase.

We describe the identification and characterization of a transcription factor encoded by the atf1+ gene of the fission yeast Schizosaccharomyces pombe. The factor Atf1, contains a bZIP domain at its C-terminus with strong homology to members of the ATF/CREB family of mammalian factors and in vitro binds specifically to ATF/CRE recognition sites. Furthermore the ATF-like binding activity detected in extracts from fission yeast cells is entirely lost upon deletion of the atf1+ gene. Upon growth to saturation, fission yeast cells exit the mitotic cycle and enter a G0-like stationary phase. However, on rich medium, entry of atf1- cells into stationary phase is restricted and they rapidly lose viability; this does not occur on minimal medium unless cAMP levels are raised. Thus stationary phase entry appears to be regulated negatively by cAMP and positively by Atf1. atf1- cells are also sterile and this sterility appears to be due to a combination of two defects: first, upon nitrogen starvation the majority of atf1- cells fail to arrest in the G1 phase of the cell cycle and second, the induction of ste11+ expression is lost. Thus expression of ste11+ represents a second example of an event that is negatively regulated by the cAMP pathway and positively regulated by Atf1. Despite their close association however, these two regulatory pathways function independently and Atf1 activity is not directly modulated by cAMP levels or mutations that alter the activity of components of the cAMP signalling pathway. Thus Atf1 is a transcription factor that plays an important role in the response of cells to adverse environmental conditions, which is to exit the mitotic cell cycle and either sexually differentiate or enter a resting state.

Activating Transcription Factor 1↗
PubMed1987

Growth and sexual development of indigenous West African boars.

60 indigenous West African boars were slaughtered in groups of five each per month at ages from one to twelve months, and the body weights and the weights of several parts of the reproductive tract were determined. It was found that the growth rate of the reproductive organs is not uniform throughout these twelve months. Up to the fourth month there was a lower growth rate, followed by a strong increase up to the sixth month, and finally a slower growth period up to twelve months of age. The growth rates of the testes and epididymides correlated with the body growth rates, strongly between the testes and the body weight in the first four months, between epididymides and body weight in the fifth and sixth months, between testes/epididymides and body weight from the seventh to the ninth month, and after that until the twelfth month between testes/vesicular glands and body weight.

Africa, Western↗
PubMed1983

Male sexual development in the nonhuman primate. III. Sertoli cell culture and age-related differences.

Homogenous preparations of primary Sertoli cell cultures were obtained from the testes of the macaque of different ages. The characteristics of Sertoli cells were confirmed by electron microscopy. Sertoli cell cultures were segregated into three developmental age groups: prepubertal, pubertal, and adult. The highest response to follicle-stimulating hormone [FSH (NIH-FSH-S13) as measured by cAMP and testosterone to estradiol conversion occurred in Sertoli cells from pubertal animals, whereas the responses were diminished in cells from both younger and older animals. Specific binding of 125I-human FSH was also increased in Sertoli cells prepared from pubertal animals when compared to cells from the other two age groups. These data demonstrate: 1) the utility of primate Sertoli cells as an in vitro model, and 2) the age-related differences in monkey Sertoli cell response to FSH and to specific FSH receptor binding.

Age Factors↗
PubMed1999

Targeted mutagenesis of the endogenous mouse Mis gene promoter: in vivo definition of genetic pathways of vertebrate sexual development.

Mutations were introduced into conserved steroidogenic factor 1 (SF1)- and SOX9-binding sites within the endogenous mouse Mullerian inhibiting substance (Mis) promoter. Male mice homozygous for the mutant SF1-binding site correctly initiated Mis transcription in fetal testes, although at significantly reduced levels. Surprisingly, sufficient MIS was produced to eliminate the MUllerian ducts. In contrast, males homozygous for the mutant SOX9-binding site did not initiate Mis transcription, resulting in pseudohermaphrodites. These studies suggest an essential role for SOX9 in the initiation of Mis transcription, whereas SF1 appears to act as a quantitative regulator of Mis transcript levels, perhaps for influencing non-Mullerian duct tissues. Comparative studies of Mis expression in vertebrates indicate that the Mis promoter receives transcriptional inputs that vary between species but result in the same functional readout.

Animals↗
PubMed1976

Effect of photoperiod upon age and maintenance of sexual development in female Coturnix coturnix japonica.

Coturnix kept in a 14L:10D photoperiod from hatch began to lay their first eggs at a mean age of 42.8 days (range 38-55). Approximately 2/3 of Coturnix held from hatch in photoperiods of 6L:16D light were laying at 165 days of age. Mean age at first egg was 112.7 days (range 68-162 days) in 8L:16D and 130.8 days (range 117-158 days) in 6L:18D photoperiod. Coturnix transferred from a non-stimulatory (8L:16D) photoperiod to a stimulatory one (14L:10D or 24L) begun laying in 15-20 days if less than 140 days old, and in about 5 days if greater than 140 days old, when trasferred. Birds which has spontaneously begun to lay in an 8L:16D photoperiod did not stop laying when the photoperiod was reduced to 6L:18D. Those which began laying under 14L:10D photoperiod ceased laying in about 15 days if 89 or fewer days old when switched to 8L:16D, or in about 6 days if 140 or more days old. Those switched from 14L:10D to 6L:18D ceased laying in about 13 days when 76 days old, and 7 days when 89 days old.

Age Factors↗
PubMed1990

Serum bioactive follicle-stimulating hormone levels in girls with precocious sexual development.

We studied the serum immunoreactive (immuno) and bioactive (bio) FSH concentrations in 16 prepubertal children (1.3-9 yr old), 6 girls with premature thelarche (0.8-2 yr old), and 9 girls with central precocious puberty (2.5-9.3 yr old). The serum bio-FSH was measured by the granulosa cell aromatase bioassay. The basal serum bio-FSH levels were not significantly different in patients with central precocious puberty (6.4 +/- 1.5 IU/L), premature thelarche (7.5 +/- 0.5 IU/L), and prepubertal controls (4.4 +/- 0.7 IU/L). However, the peak responses of both serum immuno- and bio-FSH levels to iv GnRH were higher in patients with premature thelarche (immuno-FSH, 29.3 +/- 2.3 IU/L; bio-FSH, 100.7 +/- 12.2 IU/L) than in those with central precocious puberty [immuno-FSH, 17.5 +/- 3.1 IU/L (p less than 0.05); bio-FSH, 42.4 +/- 9.8 IU/L (p less than 0.01)]. This suggests that in children with premature thelarche, there is a predominant immuno- as well as bio-FSH response to GnRH. After 12 months of GnRH agonist therapy, both serum immuno- and bio-FSH levels were suppressed in patients with central precocious puberty. The differences in clinical presentation between central precocious puberty and premature thelarche cannot be explained by the differences in FSH bioactivity.

Biological Availability↗
PubMed1989

Further evidence that prolactin controls the prepubertal sexual development in the female rat.

To assess the role of prolactin (PRL) in the puberty onset and the ovarian aromatase activity, hyper- and hypoprolactinemic conditions were induced by treating chronically prepubertal female rats with PRL and bromocriptine, respectively. Injection of rat PRL (5 micrograms, twice daily) from day 20 onward advanced the day of vaginal opening. By contrast, the suppression of PRL release by bromocriptine, which was provided in the drinking water at a concentration of 40 micrograms/ml, caused a significant delay in the age of occurrence of vaginal opening. This bromocriptine-induced delayed puberty was prevented by the concomitant administration of exogenous PRL, suggesting that the effect of bromocriptine is exerted through its suppressive effect on the endogenous PRL release. The in vitro release of estradiol by the ovaries from 30-day-old rats treated with PRL was found to be higher than that from the control animals, when the ovaries were perifused for 6 h with an excess of androstenedione. On the other hand, the ovaries perifused in the presence of androgen produced less estradiol in the bromocriptine-treated rats than in their controls. It appears, therefore, that PRL is more likely related to the aromatase activity in the maturing ovary. These results suggest that PRL may be one of the factors that regulate the timing of puberty onset by influencing the aromatase activity in the ovary.

Animals↗
PubMed1985

Growth and sexual development in children with meningomyelocele.

Forty-five children (25 girls; 20 boys) with meningomyelocele (MMC) were assessed for growth, skeletal maturation and pubertal development. The spinal defects were operated on shortly after birth and all children required cerebral drainage for hydrocephalus. Standard deviation scores for height, sitting height, sub-ischiac leg length, head circumference, weight and bone age were compared with aged-matched data from a normal Swiss population. The children with MMC were shorter (height SDS boys -2.34 +/- 1.57; girls -2.01 +/- 1.57, mean +/- SD, P less than 0.0005), secondary to a decrease in trunk and lower limb length: Arm length was normal. The head circumference was increased, significantly in the girls (SDS + 1.49 +/- 1.21, P less than 0.005). Weight was decreased in both sexes, this being significant in the boys (SDS -1.11 +/- 1.23, P less than 0.005); however, comparison of weight with height suggested that children with MMC were relatively obese. Bone age was significantly advanced in both boys (SDS + 1.07 +/- 2.13, P less than 0.025) and girls (SDS + 1.36 +/- 1.77, P less than 0.0001). Secondary sex characteristics appeared early in both boys and girls and one girl and one boy presented with puberty advanced by several years. Cryptorchidism occurred in 25% of boys with MMC.

Adolescent↗
PubMed1991

Influence of age at nutritional restriction on growth and sexual development of gilts.

Large White females were fed on a plane of nutrition close to ad libitum during the entire experimental period (CTRL group, n = 48) or restricted during a limited period of their growth (RP1 group: 28-62 kg, RP2 group: 64-96 kg, RP3 group: 97-131 kg, n = 48/group). Blood samples were taken before 200 and 230 days of age in order to detect cyclic gilts by assaying their progesterone levels. Animals were slaughtered at approximately 260 d of age and their genital tracts were examined. Overall feed intake, feed conversion ratio and daily gain were significantly lower in restricted than in CTRL gilts (average daily gain: 678, 680, 668 and 741 g/day respectively in RP1, RP2, RP3 and CTRL groups, P less than 0.05). At slaughter, animals from the 3 restricted groups has similar live weights but were lighter (152 vs 164 kg live weight, P less than 0.05) and leaner than CTRL (fat thickness: 29.5, 30.5, 28.0 and 34.1 mm respectively, in RP1, RP2, RP3 and CTRL groups). Respectively, 9, 43 and 76% of the gilts were puberal at 200, 230 and 260 days of age. The percentage of cyclic females was not influenced by treatment at 200 and 260 days of age while it was higher in CTRL (50%) and RP1 (56%) groups than in RP2 (35%) and RP3 (29%) groups at 230 days of age (P less than 0.05). At 260 days of age, ovarian and genital tract weights were not influenced by treatment either in prepuberal or in cyclic gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

The effects of growth hormone therapy on spontaneous sexual development.

We have carried out a prospective randomised study in 52 (46 male, 6 female) children with isolated growth hormone (GH) deficiency treated with a GH regimen of 15 IU/m2/week administered as a daily subcutaneous injection. At the onset of the pubertal growth spurt, the patients were randomised to receive either an unaltered regimen (26 males, 1 female) or 30 IU/m2/week (20 males, 5 females). There was no change in the frequency of GH administration. The number of females in this study was too small to give a meaningful result. In contrast, the boys treated with either dose regimen showed no significant alteration in growth rate, but there was a faster than normal progression in pubertal maturation. It is concluded that the optimum final height of children with isolated GH deficiency may not be achieved in patients without the therapeutic manipulation of the onset and/or duration of puberty. 16 short normal children (9 males, 7 females) were treated with GH in a regimen of 25 IU/m2/week (range: 20-30) as a daily subcutaneous injection. The mean age for the onset of GH treatment was 11.5 and 11.0 years in the boys and girls, respectively. Our data suggest that both boys and girls had a more rapid rate of pubertal maturation than normal. It may be that in terms of final height prognosis, the events of puberty related to GH treatment counterbalance the improvement in growth prognosis during prepuberty.

Adolescent↗
PubMed1986

Changes in circulating levels of immunoreactive follicle stimulating hormone, luteinizing hormone, and testosterone during sexual development in the rhesus monkey, Macaca mulatta.

Basal serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) and the responsiveness of these hormones to a challenge dose of luteinizing hormone releasing hormone (LHRH), were determined in juvenile, pubertal, and adult rhesus monkeys. The monkey gonadotrophins were analyzed using RIA reagents supplied by the World Health Organization (WHO) Special Programme of Human Reproduction. The FSH levels which were near the assay sensitivity in immature monkeys (2.4 +/- 0.8 ng/ml) showed a discernible increase in pubertal animals (6.4 +/- 1.8 ng/ml). Compared to other two age groups, the serum FSH concentration was markedly higher (16.1 +/- 1.8 ng/ml) in adults. Serum LH levels were below the detectable limits of the assay in juvenile monkeys but rose to 16.2 +/- 3.1 ng/ml in pubertal animals. When compared to pubertal animals, a two-fold increase in LH levels paralleled changes in serum LH during the three developmental stages. Response of serum gonadotrophins and T levels to a challenge dose of LHRH (2.5 micrograms; i.v.) was variable in the different age groups. The present data suggest: an asynchronous rise of FSH and LH during the pubertal period and a temporal correlation between the testicular size and FSH concentrations; the challenge dose of LHRH, which induces a significant rise in serum LH and T levels, fails to elicit an FSH response in all the three age groups; and the pubertal as compared to adult monkeys release significantly larger quantities of LH in response to exogenous LHRH.

Animals↗
PubMed1985

Effect of energy intake after weaning on the sexual development of beef bulls. I. Semen characteristics and serving capacity.

Simmental and Hereford bulls were individually fed varying levels of the same diet to determine the effects of energy intake after weaning, degree of fatness, and short-term weight change on reproductive characteristics of yearling beef bulls. For 200 d (ending in May), 29 Simmentals were fed an average of 14.6, 19.2 or 23.8 Mcal and 27 Herefords were fed 13.4, 17.5 or 22.2 Mcal metabolizable energy per bull daily. Bulls then were adjusted to a roughage diet for 10 d before grazing brome pasture for 38 d (ending in June). Energy level did not affect motility or sperm morphology of semen collected with an artificial vagina in May and June. High energy levels were not detrimental to bull performance during a 30-min serving-capacity test in May or June. Backfat thickness was not related to semen characteristics or serving capacity. Amount of weight lost from May to June did not affect the semen quality or serving capacity of Herefords. Those Simmental bulls that had a more positive weight change from May to June had a more favorable change in semen quality from May to June (P less than .05) due to lower semen quality in May (P less than .05). The high level of energy was not detrimental to semen characteristics or serving capacity. Some of the Simmental bulls may have been underfed for maximum semen quality at the beginning of the pasture period. Within the normal range of energy fed to beef bulls from weaning to the beginning of the breeding season as yearlings, it may be more likely to underfeed breeds of large mature size than to overfeed British breeds.

Animals↗
PubMed1983

Influence of season on sexual development in heifers: age at puberty as related to growth and serum concentrations of gonadotropins, prolactin, thyroxine and progesterone.

An experiment was done to test the hypothesis that seasonal changes in environment during the first and second 6 months of life influence age at puberty in heifers. Twenty-eight Angus X Holstein heifers, born in March (M) or September (S), were reared under natural conditions until 6 months of age. From 6 to 12 months of age, heifers were reared in environmental chambers programmed to simulate seasonal changes in temperature and photoperiod characteristic of spring, summer and early autumn (Sp-F chamber) or autumn, winter and early spring (F-Sp chamber). S were younger (P less than 0.06) at puberty than M, and Sp-F were younger (P less than 0.08) than F-Sp for both M and S. Mean ages at puberty were 295 for S, Sp-F; 319 for S, F-Sp; 321 for M, Sp-F and 346 days for M, F-Sp. Average daily gain (ADG) between 6 and 9 months of age [1.03 kg/day (S) vs. 0.91 kg/day (M)] and mean concentrations of serum luteinizing hormone (LH) between 6 and 7 months of age [3.45 ng/ml (S) vs. 0.47 ng/ml (M)] were greater (P less than 0.01) for S than M, suggesting an association between these traits and date of birth effects on age at puberty. Differences in these traits did not seem to be involved in the chamber effect on age at puberty, since ADG from 6-9 months of age was greater (P less than 0.05) for F-Sp heifers and chamber did not generally affect LH concentrations. Serum concentrations of follicle-stimulating hormone (FSH) were not significantly influenced by month of birth or chamber, but concentrations tended to decrease with age. Serum concentrations of thyroxine (T4) were higher in M than S at 6 months of age (7.8 micrograms/dl vs. 6.3 micrograms/dl) but not at other times, and chamber did not have a significant affect. Prolactin (Prl) concentrations paralleled patterns of temperature and day length and did not appear to be related to age. Although cattle are not seasonal breeders, these results demonstrate that season of birth and season of attainment of puberty influence age at puberty in heifers. Season may have influenced age at puberty by affecting serum concentrations of LH or Prl, or growth rate.

Animals↗
PubMed2002

Effects of active immunization against GnRH on serum LH, inhibin A, sexual development and growth rate in Chinese female pigs.

Surgical castration of young female pigs is common practice in Chinese pig farming today. The purpose of the present study is to investigate anti-GnRH immunization as a practical alternative to surgical castration for female pigs. Thirty-six Chinese female crossbred pigs (Chinese Yanan x Yorkshire) were selected from 12 litters, three pigs from each litter, at the age of 10-13 weeks. One pig from each litter was immunized with 62.5 microg D-Lys6-GnRH-tandem-dimer peptide conjugated to ovalbumin in Specol adjuvant at Week 0 (0 week post-vaccination, wpv), and a booster vaccination was given 8 weeks later (8 wpv). Its intact and castrate littermates (surgically castrated at the time of weaning, i.e. at 6 weeks of age) were administered the vehicle and served as controls. Antibody titers, serum LH and inhibin A were determined at the day of first vaccination, every 4 weeks thereafter and at the day of slaughter (18 wpv). At slaughter, ovaries were inspected for the presence of follicles and corpora lutea, and ovarian and uterine weights were recorded. Ten of twelve immunized pigs responded well to the immunization (immunocastrated animals), while the remaining two pigs responded poorly (nonresponders). Antibody titres in immunocastrated animals steadily increased after immunization, became maximal at 12 wpv and remained high until slaughter. Serum LH levels were reduced (P < 0.05) in immunocastrated pigs as compared to intact controls and surgical castrates. Serum inhibin A levels decreased after vaccination, and equaled surgical castrate levels from 8 wpv until the end of the experiment. Ovarian and uterine weights (1.3 +/- 0.2 and 43.9 +/- 11.4 g, respectively; mean +/- S.E.M.) were significantly lower (P < 0.05) in immunocastrates than in intact controls (9.4 +/- 1.1 and 390.9 +/- 67.2 g, respectively). Antibody titers were significantly lower (P < 0.05) in nonresponders than in immunocastrated pigs from 12 wpv to slaughter. Ovarian and uterine weights were similar in nonresponders and in intact controls. Macroscopically, no follicular structures were found in ovaries of immunocastrated pigs, while large follicles or corpora lutea were observed in the ovaries of both nonresponders and intact controls. Although not significant, immunocastrates had a numerically higher average daily gain than surgical castrates and intact controls (0.74 +/- 0.04 versus 0.66 +/- 0.04 versus 0.66 +/- 0.03 kg per day, respectively; mean +/- S.E.M., P = 0.09). Results obtained in the present study demonstrate that anti-GnRH immunization can be an attractive alternative to surgical castration for Chinese crossbred female pigs. Our results also question the beneficial effect of surgical castration on growth as compared to intact controls.

Animals↗
PubMed2002

Active immunization against gonadotrophin-releasing hormone in Chinese male pigs: effects of dose on antibody titer, hormone levels and sexual development.

The objective of this study was to determine the optimal dose of a GnRH vaccine for immunocastration of Chinese male pigs, based on immune, endocrine and testicular responses. Forty-two crossbred (Chinese Yanan x Large White) male pigs were randomly assigned to one of the five treatments as follows: (I) 0 microg (control, n=8); (II) 10 microg (n=8); (III) 62.5 microg (n=8); (IV) 125 microg (n=8); (V) 250 microg (n=10), D-Lys6-GnRH tandem dimer (TDK) peptide equivalent of conjugate (TDK-OVA), using Specol as the adjuvant. Pigs were immunized at 13 and 21 weeks of age and were slaughtered at 31 weeks of age. Blood samples for antibody titer and hormone assays were collected at 13, 21, 24 and 31 weeks of age. At these time-points, testis size was also measured. At slaughter, testis weight was recorded and fat samples were collected for androstenone assay. Four animals, one out of each immunized group, responded poorly to the immunization (non-responders). At slaughter, serum testosterone and LH levels, fat androstenone levels and testis size/weight of these non-responders were similar to those in control animals. Antibody titers of non-responders were substantially lower (P<0.05) than in other immunized pigs. For the animals that responded well to the immunization (immunocastrated pigs), serum testosterone and LH levels, fat androstenone levels and testis size or weight were reduced (P<0.05) as compared to either controls or non-responders, at all doses tested. There was a significant effect of dose of TDK-OVA on antibody titers. The overall mean antibody titers in the 62.5 or 125 microg dose group (53.6 and 50.5% binding, respectively) were significantly higher than in the 10 or 250 microg group (39.2 and 40.24% binding, respectively). At slaughter, there was a significant dose effect on testis size or weight and on serum testosterone levels, but there was no dose effect on serum LH levels and fat androstenone levels. Testis size or weight in the 10 microg group was reduced to a lesser extent (P<0.05) than in the three higher dose groups. At slaughter, in comparison to controls, mean testis size of immunocastrated pigs in treatments II-V was reduced to 55, 21, 33 and 25%, respectively, whereas testis weight was reduced to 39, 12, 18 and 14%, respectively. Reduction of testis size and/or weight is important for visual assessment of castration at the slaughterline, therefore, it is concluded that a dose of 10 microg peptide is not suitable. We conclude that, within the dose-range studied, the 62.5 microg dose is optimal for future GnRH immunization studies or future practical use in immunocastration of Chinese male pigs.

Adipose Tissue↗