Effects of 4-Nonylphenol on Sex Differentiation and Puberty in Mosquitofish (Gambusia holbrooki)

Three days post-parturition mosquitofish were exposed to different concentrations of 4-NP following a semi-static protocol. Exposure lasted up to the development of male anal fin in male individuals of the control group. Exposure to 50 g/L 4-NP resulted in 100% females considering secondary sexual characters, while external sex-ratio did not statistically differed from unity in control group. In group exposed to 0.5 and 5.0 g/L sex-ratio did not differ from unity but incompletely developed gonopodium was observed in several individuals. Individuals exposed to 50 g/L 4-NP exhibited female or undeveloped gonads, while gonadal sex-ratio did not statistically differ from unity in control group. Percentage of undeveloped gonads increased with 4-NP concentration. Additional observations demonstrated hepatic histopathology in fish exposed to the highest concentration and growth reduction dependent on 4-NP concentration. In a complementary experiment, extensive metabolism of [³H]4-n-NP was characterized following in vivo exposure of juvenile mosquitofish suggesting that metabolism could modulate 4-NP toxicity. This study suggests susceptibility of early life stages of mosquitofish to endocrine modulators with regard to development of reproductive capabilities.     

Changes in hypothalamic dopamine D-2 receptors during sexual maturation in male and female rats

We have examined variations in hypothalamic dopamine D-2 receptor levels occurring during sexual maturation in male and female rats, using a [3H]domperidone radioligand binding assay. A major decrease in D-2 receptor levels was observed during sexual development, and was accompanied by the appearance of a sexual dimorphism in receptor levels, which appeared to be the result of neonatal sexual differentiation. These changes may be linked with the alterations in hormone levels which occur during sexual maturation.     

DISCORDANT BONE MATURATION OF THE HAND IN CHILDREN WITH PRECOCIOUS PUBERTY AND CONGENITAL ADRENAL HYPERPLASIA

ABSTRACT
Vejvoda, M. and Grant, D. B. (The Hospital for Sick Children, London WCIN 3JH, England). Discordant bone maturation of the hand in children with precocious puberty and congenital adrenal hyperplasia. Acta Paediatr Scand, 70: 903, 1981.-Difference between the bone maturation scores for the tubal and carpal bones of the hand and wrist were assessed by the method of Tanner et al. on X-rays from 10 children with precocious puberty and 10 children with late-diagnosed congenital adrenal hyperplasia, and compared with results in 20 normal children. Scores for the tubular bones were significantly more advanced than those for the carpal bones in both groups of patients, emphasizing the need for caution when using standards derived from normal children to assess bone age in children with markedly accelerated bone maturation.     

PARENTERAL NUTRITION IN THE CORRECTION OF GROWTH FAILURE IN CHRONIC INFLAMMATORY BOWEL DISEASE

Impaired linear growth and delayed sexual maturation are important features of Crohn's disease. Parenteral nutrition for a few weeks can accelerate growth and allow puberty changes.     

Changes from puberty to adulthood in the concentration, motility and morphology of mouse epididymal spermatozoa

A systematic study of the concentration, motility and morphology of epididymal spermatozoa was undertaken in mice of the OF1 strain, in order to characterize the changes observed during puberty. The comparative development of these 3 parameters was followed from days 30 to 90. A detailed morphological system of classification was established covering both individual and multiple abnormalities. At puberty, the first spermatozoa to appear were few in number, showed poor motility and were extremely atypical. Subsequently, the number of atypically-shaped spermatozoa diminished, and their concentration and motility exhibited parallel increases. At 60 days, the values for these 3 parameters and the proportions of normal and abnormal spermatozoa became stable. During puberty, various forms of disruption of the midpiece as well as the presence of extremely atypical detached flagella resulted in a special pattern of sperm morphology, although all of these abnormal features disappeared at 40 days.     

Pinealectomy advances the time of development of steroid feedback on luteinizing hormone release in immature female rats

The effect of pinealectomy (Px) on the development of steroid positive feedback on luteinizing hormone (LH) release was examined in female rats subjected to surgery at 10 days of age. Estradiol-progesterone injection decreased serum LH in sham Px or intact controls younger than 20 days, while a significant LH release was found at day 22; Px rats showed a steroid-induced LH depression only at day 16, a positive feedback being detectable at day 20, 2 days earlier than in sham Px or intact rats. Daily injections of 10–50 μg melatonin to intact rats disrupted the LH negative feedback response at day 20, and diminished steroid-induced LH release at day 24.     

Regional differences of the sleep electroencephalogram in adolescents

The sleep electroencephalogram (EEG) was recorded from anterior (Fz/Cz) and posterior (Pz/Oz) bipolar derivations in two developmental groups: 20 pre- or early pubertal (Tanner 1/2, mean age 11.4 +/- 1.1 years, 11 boys) and 20 late pubertal or mature adolescents (Tanner 4/5, 14.1 +/- 1.3 years, 8 boys). A sleep-state independent reduction of EEG power over almost the entire frequency range was present in Tanner 4/5 compared with Tanner 1/2 adolescents. Spectral characteristics of the sleep EEG yielded state- and frequency-dependent regional differences that were similar in both developmental groups. Anterior predominance of power in delta and sigma ranges occurred in non-rapid eye movement sleep. Rapid eye movement sleep EEG power was greater in low delta, alpha, and sigma ranges for the posterior derivation and in theta and beta ranges for the anterior derivation. The decay rate of the sleep homeostatic process--reflected by the exponential decline of the 2-Hz EEG power band across the sleep episode--did not differ for derivations or groups. These results indicate that the nocturnal dynamics of sleep homeostasis are independent of derivation and remain stable across puberty.     

Testicular microlithiasis: an unreported feature of McCune-Albright syndrome in males

OBJECTIVE: To ascertain the incidence of testicular microlithiasis (TM) in boys with McCune-Albright syndrome (MAS). STUDY DESIGN: Study population consisted of 8 boys with MAS whose medical records were reviewed with emphasis on their past genitourinary histories. All of the boys underwent a clinical and ultrasonographic (US) scanning of the scrotal and inguinal regions. US results in boys with MAS were compared with those obtained in two control populations consisting of 20 healthy subjects and 12 boys with idiopathic and untreated central precocious puberty (CPP). RESULTS: Clinical examination revealed urological abnormalities in no patients, whereas US showed a typical picture of TM in 5 of 8 boys. TM was observed in none of the subjects belonging to control populations (v=15.2 and 11.3, respectively; P <.001). CONCLUSIONS: In a series of 8 boys with MAS we demonstrated a high prevalence (62%) of TM that was associated with neither malignant nor nonmalignant conditions. This finding is unlikely to be only occasional, considering the very low prevalence of TM reported until now in healthy children and young adults and in our results in control populations. TM may be another marker for MAS.