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PubMed1983

Changes in gonadotrophin binding to rat ovaries during sexual maturation.

Changes in LH and FSH binding to rat ovaries during sexual maturation were measured by in vitro binding assay and autoradiography. Ovaries were obtained from rats at various ages ranging from 5 till 35 days of age. Animals older than 35 days of age were classified in three groups: anoestrus (uterine weight below 60 mg), early pro-oestrus (uterine weight 60-120 mg) and pro-oestrus (uterus distended with fluid). Measurements were made of specific binding of radioiodinated hCG and rFSH to ovarian homogenates (day 5-35) and to granulosa cells isolated from the largest follicles (day 35-pro-oestrus). The earliest age at which specific hCG and FSH binding could be demonstrated was day 11. Thereafter hCG binding to ovarian homogenates, expressed in CPM/microgram DNA, increased with age. Specific binding of hCG to granulosa cells increased from 1000 CPM/microgram DNA at day 35 to 4000 CPM/microgram DNA at pro-oestrus. FSH binding to ovarian homogenates increased till day 21 and remained fairly constant thereafter. Autoradiography revealed the presence of hCG binding to interstitial tissue and thecal cells. hCG binding to granulosa cells was only found in large pre-ovulatory follicles present at early pro-oestrus and pro-oestrus. FSH binding was observed to granulosa cells of all types of follicles, but not to interstitial and thecal cells. The results demonstrate that during sexual maturation FSH binding to granulosa cells remains constant, whereas LH binding to interstitium and theca and ultimately to granulosa cells increases with age suggesting an increased responsiveness of the ovaries to LH.

Animals↗
PubMed1996

Sexual maturity in British breeds of goat kids.

Eight male kids of British Sannen and one each of the British Alpine and British Toggenberg breed, born between the last week of February and first week of March 1990, were used. From the age of 12 weeks, they were monitored every week for body and testicular growth and sexual development, until they attained sexual maturity. The development of the sexual behaviour was a gradual process. From 12 weeks of age, the body weight increased at a constant rate. Testicular development, however, showed a biphasic pattern; the testis size increased rapidly between 12 and 20 weeks of age and was followed by a period of slow growth. Sexual maturity occurred at a mean age of 172.7 +/- 4.47 days, and at a mean body weight of 31.25 +/- 1.50 kg when the mean values of scrotal circumference, testis diameter and paired testes width were 24.13 +/- 0.47 mm, 54.01 +/- 1.26 mm and 88.31 +/- 1.61 mm, respectively. In most kids, the quality of the first ejaculate was good, although it varied widely between animals. It appeared that sexual maturity in British goat kids occurs at a younger age than in different breeds in other parts of the world that have been reported in the literature.

Age Factors↗
PubMed1988

Roles of age, body weight and composition in the initiation of sexual maturation of Japanese quail (Coturnix coturnix japonica).

1. The roles of chronological age, body weight and body composition in the initiation of sexual maturation of Japanese quail (Coturnix coturnix japonica) were investigated by imposing an inhibitory photoperiod (IP), and by the intramuscular injection of turkey growth hormone (GH) or antisera to turkey growth hormone (AGH). 2. Absence of sexual maturity in the IP treatment was accompanied by reduced testis and ovary-oviduct weights, and an increased breast muscle weight expressed as a proportion of body weight. 3. Antisera to turkey growth hormone (AGH) did not completely inhibit the metabolic activities of endogenous GH. 4. The roles of chronological age, body weight and body composition in the initiation of sexual maturity were inseparable.

Aging↗
PubMed2005

Do sexual maturation stages affect flexibility in adolescent boys aged 14 years?

AIM: Pubertal changes constitute a background for development of motor abilities and flexibility as an important component of physical fitness. The aim of the present study was to investigate whether the flexibility is actually related to sexual maturation stages in adolescent boys. METHODS: This cross-sectional study was conducted on 69 healthy boys aged 14 years. Before testing, all participants performed a 3 min warm up and static stretch routine, emphasizing the lower body. The flexibility tests were performed in a counterbalanced design. Sit-and-reach test and goniometric measurement of hamstring flexibility was administered. The results of flexibility tests and body measures were analysed for cross-sectional comparison. Groups were formed according to Tanner's classification and consisted of boys in Stage II, III, IV, V, respectively. RESULTS: The results of sit and reach test scores and goniometric measurements did not correlate with age in months, height, weight and BMI; and furthermore they did not correlate with the sexual maturation stages (p>0.05). The sit and reach test scores were significantly correlated with goniometric measurements (right: r=0.653, p=0.00; left: r=0.638, p=0.00). CONCLUSIONS: The results suggest that sexual maturation stages in pubertal period would not be effective in determining the flexibility. Besides, sexual maturation is not a cause of decreased flexibility in adolescent boys aged 14 years.

Adolescent↗
PubMed1996

Sexual maturation and racial differences in blood pressure in girls: the National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVE: To evaluate racial differences in blood pressure in girls aged 9 to 10 years in the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS) and to evaluate the extent to which racial differences in blood pressure are explained by other factors, including sexual maturation and body size. METHODS: The NGHS enrolled 539 black and 616 white girls aged 9 years, and 674 black and 550 white girls aged 10 years. Racial differences in blood pressure were examined. Relationships of stage of sexual maturation, height, and skinfold thickness with systolic and diastolic blood pressure were evaluated by multiple regression analysis. RESULTS: The black girls had significantly higher systolic (102.0 +/- 8.90 vs 100.5 +/- 9.42 mm Hg, p <0.001) and diastolic (58.0 +/- 12.0 vs 56.5 +/- 12.51 mm Hg, p <0.01) blood pressures than the white girls. The black girls were also more advanced in sexual maturation and were taller (142.9 +/- 7.94 vs 139.6 +/- 7.05, p <0.001) and heavier (39.6 +/- 11.24 vs 35.3 +/- 8.73 kg, p <0.001) than the white girls. Both systolic and diastolic blood pressure were significantly correlated with level of maturation, height, weight, and sum of skinfolds. Stage of maturation was found to account for the difference in blood pressure between black girls and white girls. In a multiple regression analysis, controlling for height (for diastolic blood pressure) and for both height and sum of skinfolds (for systolic blood pressure) eliminated the effects of race and stage of maturation on blood pressure. CONCLUSION: Racial differences in blood pressure were observed for 9- and 10-year-old girls and are explained by the fact that black girls were more mature than white girls. The effect of sexual maturation on blood pressure appears to operate through height and body fat. The effect of obesity may be more important for systolic than for diastolic blood pressure. Continuation of racial differences in blood pressure may result in a higher prevalence of hypertension for black women.

Adipose Tissue↗
PubMedDate not supplied

Segment-specific decrease of both catecholamine concentration and acetylcholinesterase activity are accompanied by nerve refinement in the rat cauda epididymis during sexual maturation.

In the present work, histochemical and biochemical studies were conducted to analyze changes in the pattern of autonomic innervation during sexual maturation, using the rat epididymis as a model. Glyoxylic acid histochemistry and immunohistochemical studies against dopamine beta-hydroxylase (DbetaH) and acetylcholinesterase (AChE) indicated a reduction in the amount of catecholaminergic and AChE-positive neurons, fibers, and puncta detected in the cauda epididymis of adult rats (120 days old), when compared to immature (40 days) and young adult (60 days) animals. No obvious age-related variations were detected in the few catecholaminergic and AChE-positive fibers and puncta present in the caput region. AChE-positive fibers were found sorting out among epithelial cells and ending free upon the epithelial surface or into the tubular lumen of the cauda region of adult rats. Furthermore, a positive staining for AChE in epithelial cells was also detected in the caput and cauda epididymis in all ages studied. Biochemical analysis confirmed a significant decrease in noradrenaline concentration as well as AChE activity in the cauda epididymis with sexual maturation. Immunohistochemical studies against microtubule-associated protein 1B (MAP 1B), a neuronal cytoskeletal marker, further substantiated the quantitative changes observed in catecholaminergic and AChE-positive neuronal elements in the cauda epididymis. Thus, our results documented segment-specific variations in noradrenaline concentration and AChE activity during epididymal sexual maturation and suggest that such variations result, at least in part, from the refinement of the autonomic innervation pattern with age.

Acetylcholinesterase↗
PubMed1995

Photoperiodic control of sexual maturation in Muscovy drakes.

The influence of photoperiodic control on reproductive development was investigated in Muscovy drakes by the use of night-interruption photoschedules consisting of a main photofraction of 6 hr and a secondary photofraction of 1 hr, interrupting the dark period 6 hr (Group A), 8 hr (Group B), 10 hr (Group C), and 12 hr (Group D) after dawn. Sexual maturity, assessed by the increase in plasma concentrations of luteinising hormone (LH) and testosterone, was achieved in all groups by Week 34. However, significant differences in the precocity of the rate of sexual maturation were evident on Week 27. At this time, plasma testosterone concentrations, relative to those at Week 15, had increased by 2.02, 0.29, 0.89, and 2.68 ng/ml in Groups A, B, C, and D respectively. Increases in LH concentrations followed a similar pattern. The more pronounced increases in LH and testosterone concentrations observed from Group B to Group D indicate that long days stimulate reproductive development in the Muscovy duck via a diurnal rhythm of photosensitivity. However, the nonphotostimulated increase in hormonal concentrations observed in Group A implies that a factor other than photostimulation may be involved. The dissipation of juvenile photorefractoriness by long-term short-day exposure and subsequent passive sexual maturation may explain these results. We hypothesize that the rate of sexual maturation results from a balance between the dissipation of juvenile photorefractoriness by short days and the relative strength of the photoperiodic drive as the result of long days.

Animals↗
PubMed1985

Delayed female sexual maturation. How to approach differential diagnosis.

Delayed sexual development is present when an adolescent girl fails to experience, at an age that is beyond the average for her peers, those pubertal events that are indexes of gonadal function. Adolescent girls whose sexual development is delayed can be divided into three groups: (1) those who have not menstruated but have well-developed secondary sexual characteristics, indicating that they have a functioning hypothalamic-pituitary-ovarian mechanism, (2) those with poorly developed secondary sexual characteristics whose hypothalamus and pituitary are functional but who have ovarian failure, as indicated by high levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) (hypergonadotropic hypogonadism), and (3) those with poorly developed secondary sexual characteristics whose normal ovaries are not functioning because of a hypothalamic or pituitary disorder, as indicated by low or low normal serum FSH/LH levels (hypogonadotropic hypogonadism). There are, in addition, individuals with a female habitus and external female genitalia who were reared as females but have an XY karyotype and come to the physician with a complaint of delayed female sexual maturation.

Adolescent↗
PubMed1986

Lipocyte hyperplasia and sexual maturation of Japanese quail (Coturnix coturnix japonica).

1. Hyperplastic growth of adipose tissue in Japanese quail (Coturnix coturnix japonica) was examined in relation to sexual maturity to determine whether fat cell number is fixed in mature individuals of this species. 2. Total DNA concentrations in the lipid (lipocyte) and non-lipid (stroma) fractions of collagenase (EC 3.4.24.3)-digested abdominal (retroperitoneal) fat depots were determined on a chronological-age basis from 28 to 240 d of age. The in vivo incorporation of [methyl-3H]thymidine into DNA of both the lipocyte and stroma fractions of abdominal fat from both ad lib. and restricted-fed (75% of ad lib.) females was also examined at ages before and subsequent to sexual maturity. 3. In both males and females, significant increases in abdominal fat weights at ages beyond sexual maturity were associated with increased lipocyte DNA. Regardless of the feeding regimen and stage of maturity, substantial radioactivity was recovered from both the stromal and lipocyte fractions of abdominal fat when female quail were examined 24 h after the administration of tritiated thymidine. When examined 5 d post-injection, the majority of the radioactivity was contained in the lipid fraction of collagenase-digested adipose tissue. 4. Both the total DNA content of adipose tissue and the incorporation of tritiated thymidine into adipose tissue indicated that lipocyte hyperplasia contributes to postmaturational increases in fat deposition.

Abdomen↗
PubMedDate not supplied

Relations between accelerated sexual maturation and menstrual disorders.

The author demonstrates that the phenomenon of acceleration of sexual maturation is more frequent in urban areas. The factors having a part in determining this process are multiple: psychoemotional and audio-visual ones, and have an important role. The acceleration of sexual maturation has rather negative consequences, due to the significant increase of puberal menstrual troubles.

Adolescent↗
PubMed1995

Developmental changes in immunoreactive inhibin and FSH in plasma of chickens from hatch to sexual maturity.

1. The relationship between immunoreactive inhibin and follicle-stimulating hormone (FSH) was studied in male and female chickens from hatch to sexual maturity. Plasma inhibin was estimated by a heterologous radioimmunoassay validated for use in the chicken. FSH was measured by a recently developed homologous radioimmunoassay. 2. In a cross-sectional study, blood samples and gonads were collected from chickens of both sexes at 1, 3, 5, 7, 14, 21 and 28 d after hatching and subsequently at 14-day intervals until 182 d of age. 3. In the female, plasma progesterone concentration (P4) progressively increased during sexual development. The plasma luteinising hormone (LH) concentration rose during the first week after hatching, and fluctuated thereafter, with troughs at 6 and 14 weeks and peaks at weeks 10 and 18. The plasma inhibin and FSH concentrations remained low until the start of puberty and increased simultaneously thereafter. However, from week 18 on, plasma inhibin continued to rise while plasma FSH fell. Hence, FSH and inhibin were positively correlated before puberty, but developed a negative correlation during sexual maturation. 4. In the male, plasma testosterone and LH concentrations increased 38- and 3.7-fold respectively over the period studied. Inhibin and FSH followed similar time courses and were consequently positively correlated. 5. These results suggest sex differences in the role of inhibin in regulating FSH secretion during development. The FSH-inhibin feedback loop may become operational at the onset of sexual maturity in the hens. In male chickens, the similar pattern of inhibin and FSH secretion suggests that inhibin secretion is driven by FSH.

Aging↗
PubMed1986

Effect of prenatal alcohol exposure on sexual maturation of female rat offspring.

To assess sexual maturation of female offspring from alcoholic rats, vaginal opening, body weight, prolactin (PRL), luteinizing hormone (LH) and growth hormone (GH) were followed during development. The vaginal opening in the female offspring from alcohol-fed dams was delayed compared with the offspring from both pair-fed and normally fed dams. There was an increase in plasma PRL levels together with a decrease in levels of plasma LH at the time of the opening of the vagina in rats prenatally exposed to alcohol (PEA) with respect to both control groups. The increase in PRL was the only hormonal alteration which persisted into adulthood (120 days). In general, there were no changes in levels of plasma GH between experimental and control groups. These data indicate that PEA results in a modification in secretions of PRL and LH as well as in a delay in the opening of the vagina.

Animals↗
PubMed2004

Hypothalamic nitric oxide synthase activity during sexual maturation in female rats. Effects of estrogens.

OBJECTIVES: To determine the hypothalamic activity of nitric oxide synthase (NOS, the enzyme involved in the synthesis of nitric oxide NO) during sexual maturation in prepubertal (15 days old) and peripubertal female rats (30 days old) as well as the effect of estradiol administration on this neurotransmitter system. METHODS: Hypothalamic samples containing the anterior preoptic and medial basal areas (APOA-MBH) were homogenized with HEPES 20 mM, pH = 7.4 and NOS activity was determined in APO-MBH after 10 minutes of incubation by the conversion of 14C arginine to 14C citrulline. RESULTS: The hypothalamic concentration of NOS is significantly higher in peripubertal than in prepubertal rats. Treatment with EB increased significantly the activity of the enzyme in both groups compared with control and the increases was similar at both ages. CONCLUSIONS: These results clearly demonstrated that the hypothalamic NOS activity increases in peripubertal rats as compared with prepubertal animals. Estradiol has a similar stimulatory effect on hypothalamic NOS activity at both ages of sexual maturation, indicating that the increase in NOS during sexual maturation is connected with the peripubertal increase of estradiol rather than an increase in the sensitivity of the enzyme to the ovarian hormone.

Animals↗
PubMed1984

The temporal response of rat testes to hCG stimulation during sexual maturation.

Serum testosterone responses to a single sc injection of hCG (25 IU/100 g body weight) were monitored for 5 days in rats throughout sexual maturation (22-70 days). Two hours after hCG injection serum testosterone levels rose in 22, 37 and 53 day-old animals and remained elevated for 2 days, returning to control levels on day 3. This response differed markedly from the biphasic secretion of testosterone reported for adult animals. In 70 day-old animals the serum testosterone response approached that seen in adult animals. Testosterone levels were elevated 2 h after hCG injection (25.4 +/- 2.5 ng/ml) and declined significantly at 12 and 24 h to 17.1 +/- 1.0 and 16.1 +/- 3.4 ng/ml, respectively. Testosterone levels tended to increase again on days 2 and 3 (19.9 +/- 2.8 and 21.1 +/- 3.5 ng/ml, respectively) but the increase was not statistically significant. This response differed markedly to the biphasic secretion of testosterone reported for adult animals. In vitro patterns of basal and hCG-stimulated testosterone secretion by decapsulated testes following a single hCG injection also changed during sexual maturation. In 22 day-old animals the testes exhibited refractoriness to in vitro hCG stimulation at 12 h, but testes from 37 day old rats were refractory from 2 to 24 h. In vitro testosterone responses of testes from 53 and 70 day-old rats were similar to that reported for adult rats with a period of refractoriness from 12 h to 2 days. This study demonstrates that during sexual maturation in the rat alterations occur in the temporal patterns of testosterone secretion in vivo and in vitro following hCG stimulation.

Aging↗
PubMed2005

Relationship between hypothalamic-pituitary-adrenal axis responsiveness and age, sexual maturity status, and sex in Japanese quail selected for long or short duration of tonic immobility.

The influences of age (4 to 12 wk), sexual maturity status, and sex on hypothalamic-pituitary-adrenal (HPA) axis responsiveness were investigated by measuring changes in peripheral basal levels of corticosterone (B) and responses to 10 min of physical restraint in a crush cage or injection of 1-24 adrenocorticotropic hormone (ACTH) in 2 genotypes of Japanese quail divergently selected for long (LTI) or short (STI) duration of tonic immobility (TI). Although gonad development was more advanced in male STI quail, most birds were still immature at 4 wk of age, but sexual maturity was fully acquired by 6 wk of age in both sexes and genotypes. This change was associated with increases in basal B levels in both genotypes and sexes. On the other hand, HPA axis responsiveness to restraint and adrenal responsiveness to 1-24 ACTH injection remained stable in STI quail, whatever the age. Conversely, significant responses to restraint compared with basal B levels were only observed at 4 and 6 wk of age, and adrenal responsiveness increased with age in LTI quail. Moreover, higher B levels were measured in response to restraint in STI than in LTI quail, whereas similar adrenal responses were measured at 9 and 12 wk of age. We concluded that an increase in basal B levels is associated with the stage of sexual maturity acquired, but it did not affect HPA axis responsiveness or adrenal B response capacity. On the other hand, age affected HPA axis responsiveness and adrenal B response capacity in LTI quail of both sexes but not in STI quail. It is hypothesized that functional HPA axis maturity occurs after 6 wk of age in the LTI genotype, but it is reached by 4 wk of age in the STI genotype. In conclusion, the divergent selection program for TI conducted on quail resulted in changes in HPA responsiveness that probably resulted from differences in development rate and function of the adrenal glands or other upstream structures of the HPA axis.

Aging↗
PubMed1990

Developmental changes in testicular inhibin and androgen-binding protein during sexual maturation in the cynomolgus monkey, Macaca fascicularis.

Inhibin was measured by RIA in testicular extracts and plasma of cynomolgus monkeys during four stages of sexual maturation. Immunoactive inhibin levels were compared to those of another Sertoli cell secreted protein, androgen-binding protein (ABP). ABP steroid-binding (bioactive) activity was measured in testes and epididymal segments using the radiolabeled ligand [3H]dihydrotestosterone (DHT). Testicular immunoreactive inhibin concentrations were maximal in late prepubertal monkeys, 2.5-3.5 yr old, while the total testicular content of inhibin progressively increased with age into adulthood. Bioactive testicular ABP concentrations were maximal during the pubertal period of the cynomolgus monkey (3.5-4.0 yr old), while the total ABP content of the testes also increased with sexual maturation. Mean (+/- SE) plasma concentrations of inhibin and testosterone (T) in adults, 6-8 yr old (17.72 +/- 3.5 microliters inhibin equivalents/ml and 7.07 +/- 2.45 ng/ml T, respectively), were significantly higher (P less than 0.05 and P less than 0.001, respectively) than those in early prepubertal, juvenile monkeys, aged 1.5-2.5 yr (5.85 +/- 2.1 microliters inhibin equivalents/ml and 0.27 +/- 0.02 ng/ml T). The increased plasma levels of inhibin and T in adults were associated, respectively, with the increased inhibin and androgen contents of the testes in these same animals. The developmental changes in testicular steady state mRNA concentrations for the inhibin alpha-, beta A-, and beta B-subunits as well as ABP were examined during sexual maturation by Northern blot analysis using heterologous human cDNA probes. Densitometric analysis of the autoradiograms revealed that the inhibin alpha-subunit mRNA concentrations were higher than those of inhibin-beta A and -beta B and ABP mRNA during all stages of pubertal development. Although the relative concentrations of each inhibin subunit mRNA were decreased in the adult animals relative to those in the juvenile monkeys, the total amount of steady state mRNA for the subunits was greater than that in the immature animals. A similar situation existed for the ABP mRNA.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMedDate not supplied

[The effect of hydrocortisone and insulin on ribonucleic acid synthesis in the nuclei and cytoplasm of sexually mature male rat liver cells].

Prolonged administration to male sexually-mature rats weighing 180-200 g of hydrocortisone, protamine-zinc-insulin enhanced considerably the synthesis of DNA-like RNA, precursor of ribosomal RNA in the nuclei and ribosomal RNA in the cytoplasm of the liver; this increase was even more pronounced after the administration of both hormones. The data obtained were in favour of the participation of DNA-like RNA, precursor of ribosomal RNA of the nuclei and ribosomal RNA of the cytoplasm of the liver of male sexually-mature rats in the synthesis of transaminases of their liver.

Animals↗
PubMed1984

Sexual maturation and adrenal function in girls with thalassemia.

Adrenal steroid production was evaluated in 12 thalassemic girls aged between 18 and 22 years and at stage P1 of sexual maturation according to Tanner. The values found in these patients were compared with those in 12 normal girls of the same age at stage P4-5 of sexual maturation. Pregnelone, dehydroepiandrosterone, dehydroepiandosterone sulfate, progesterone, 17-OH-P, androstenedione, testosterone, dihydrotestosterone and estradiol were found to be significantly reduced (p less than 0.001) in the thalassemic group, while cortisol levels showed a slight but not statistically significant reduction. Plasma ferritin levels were greatly increased and showed a highly significant (p less than 0.001) correlation coefficient when plotted against each hormone. The present results suggest that the impaired adrenal function plays an important role in determining the delayed sexual maturation almost always present in the thalassemic patients and that this disorder may be due to iron overload.

Adolescent↗