Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes.

Background: Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties and . Exposure to these chemicals, especially during prenatal development, is of concern.

Objectives: To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes.

Presence of benzophenones commonly used as UV filters and absorbers in paired maternal and fetal samples.

Background: Previous studies have demonstrated widespread exposure of humans to certain benzophenones commonly used as UV filters or UV absorbers; some of which have been demonstrated to have endocrine disrupting abilities.

Objectives: To examine whether benzophenones present in pregnant women pass through the placental barrier to amniotic fluid and further to the fetal blood circulation.

Methods: A prospective study of 200 pregnant women with simultaneously collected paired samples of amniotic fluid and maternal serum and urine.

Insulin-like factor 3 levels in second-trimester amniotic fluid.

Background: According to animal studies, the testicular Leydig cell hormone insulin-like factor 3 (Insl3) exerts a fundamental role in abdominal testis translocation, which occurs in the beginning of the second trimester in humans. Despite this, human prenatal INSL3 production has been poorly investigated.

Methods: Amniotic fluid from 91 pregnant women undergoing amniocentesis was analyzed for INSL3 and testosterone (T) levels.

Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys.

Context: Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function.

Objective: The objective of the study was to examine whether an age-independent time trend in male serum testosterone levels exists.

Impaired Leydig cell function in infertile men: a study of 357 idiopathic infertile men and 318 proven fertile controls.

To investigate whether an impaired Leydig cell function is present in severely oligospermic men, serum testosterone (T), LH, estradiol (E(2)), and SHBG levels in 357 idiopathic infertile men were compared with levels in 318 proven fertile men. In addition, the T/LH ratio, E(2)/T ratio, and calculated free T index (cFT) were compared between the two groups.A shift toward lower serum T levels, cFT, and T/LH ratio and higher serum LH, E(2), and E(2)/T levels was observed in the group of infertile men.

Serum inhibin B and follicle-stimulating hormone levels as tools in the evaluation of infertile men: significance of adequate reference values from proven fertile men.

Inhibin B and FSH levels in 289 idiopathic infertile men were compared with reference materials consisting of 303 proven fertile men (reference group 1) and 307 healthy men from the general population with unknown fertility status (reference group 2). The diagnostic power of these two serum markers of spermatogenesis was evaluated by the use of receiver operating characteristic plot analysis, and an example of how both markers can be used simultaneously in a bivariate reference chart is presented. Inhibin B levels were significantly lower and FSH levels were significantly higher in the infertile men, compared with either reference group, but with significant overlap, especially with reference group 2.

Variation in levels of serum inhibin B, testosterone, estradiol, luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin in monthly samples from healthy men during a 17-month period: possible effects of seasons.

To obtain information on the scale of the intraindividual variation in testicular hormone, blood samples for inhibin B determination were collected monthly in 27 healthy male volunteers during a 17-month period. In addition, the traditional reproductive hormones FSH, LH, testosterone, estradiol, and SHBG were measured. The intraindividual variation in inhibin B over the study period was, on the average, 10%, corresponding to the assay variation of the inhibin B assay, indicating that most of the observed day to day variation in inhibin B levels in men could be explained by assay variation.