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Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas-liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic-pituitary endocrine function and also indicates that FSH and LH are the hormones most affected.

Objectives: The objective of the study is to evaluate the effects of levonorgestrel transferred through breast milk on thyroid stimulating hormone (TSH) and luteinizing hormone (LH) levels in full breast-fed infants., Methods: Forty healthy postpartum women and their male newborns were recruited for the study. Women were randomly allocated to two study groups: Group 1, IUD users and group 2, Norplant users. Blood and milk samples were collected on the day of IUD or Norplant insertion and 3 and 6 months later for TSH and levonorgestrel measurements., Results: The results disclosed a significant decrease in TSH levels, and a negative relationship between LNG levels and TSH concentration in breast feeding infants at 3 months after implant insertion. The lowest TSH levels were observed at 6 months in the women from group 2., Conclusions: The overall data indicate that the LNG levels transferred to fully breast-fed infants through breast milk from Norplant users significantly modified their TSH levels.

In recent years, several potent gonadotropin-releasing hormone (GnRH) analogues have become available for female contraception and one of them (buserelin) has been tested in lactating women. However, the possible effects on infants due to the transference of the analogue through breast milk have not been studied. The present work evaluated the effect of oral buserelin on urinary LH secretion in male infants. A total of 19 healthy full-term boys (aged 2-4 months) were included in the study. Infants received orally a single dose of a GnRH agonist mixed with breast milk. Urine samples were collected prior to, and 4-6 and 24 h after treatment for LH measurement. The results disclosed a significant increase in LH urine level in the sample taken 4-6 h after buserelin administration. Twenty-four hours after GnRH agonist ingestion, the LH level returned to baseline level. The present study demonstrated that GnRH analogue administered orally to infants escapes from gastrointestinal inactivation and induces a significant rise in LH levels 4-6 h after treatment.

The effects of four low doses of synthetic steroids, administered orally and starting on day 8 (group I) or on day 10 of the menstrual cycle (group II), upon LH surge, ovarian steroidogenesis, follicular maturation and menstrual cycles were studied in 10 eumenorrheic women. The results revealed that the day before the LH surge, the highest level of estrone-3-glucuronide was observed in both groups. Twenty-four hours after the last dose, the maximum urinary LH levels were recorded in groups I (day 11), and II (day 13). Pregnanediol-3 alpha glucuronide remained low during the study in group I, whereas in group II a gradual rise of this hormone starting on day 13 was registered and the highest level was found at day 21 of the menstrual cycle. Follicular maturation and ovulation were observed only in women from group II. Short and normal length cycles were recorded in groups I and II, respectively. In summary, low doses of exogenous synthetic steroids administered on day 8, but not on day 10 of the cycle, inhibit follicular maturation and ovulation.

The procedures for a systematic evaluation of the quality control of radioimmunoassay in general were described previously. In this report we present the parameters of quality control and their application to the radioimmunoassay (RIA) of pituitary gonadotrophic hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH) in serum. We present the results obtained in the intra-assay variation for the measurement of the pituitary gonadotrophic hormones in serum (LH and FSH) from 1983 to 1989. The results on bias and the inter-laboratory assessment through an external quality control scheme during the same period are also presented.