Endocrine Abstracts

It has been hypothesised that the hypothalamo–pituitary gland complex is a prime target through which environmental chemicals may alter reproductive physiology. The aim of this study was to investigate whether exposure to an environmentally relevant mix of chemicals during in utero and post-natal development can alter pituitary function. Pituitary glands were collected from 110 day-old foetuses (8 control and 8 treated) and 18 month old, post-pubertal sheep (8 control and 8 treated), born to and raised by mothers maintained on pastures fertilised using sewage sludge (Treated) or conventional inorganic fertilisers (control). Pituitaries were sectioned (5 μm) and underwent dual labelled immunohistochemistry for LHβ and ERα. Mean immunopositive cell numbers were ascertained from three areas of each pituitary and data compared using Student’s T-test. There was no effect of gender on foetal pituitary measures so data were combined for subsequent analysis. In the foetal pituitary, treatment significantly reduced the number of LHβ and ERα immunopositive cells but had no effect on the proportion of oestradiol-responsive LHβ positive cells. Treatment resulted in a significant increase in adult pituitary size in male but not female animals. There was no effect of treatment on the number of LHβ and ERα immunopositive cells in the adult female pituitary. Treated males, had significantly less LHβ positive and double labelled cells. Relative to pituitary weight, this showed that treatment had no overall effect on LHβ and ERα immunopositive cell numbers. Therefore, foetal exposure to EDCs may alter the populations of oestradiol responsive cells and LHβ positive gonadotrophs in the foetal pituitary, however, during post natal development, changes occur which mean that in the adult, no differences are seen in either of these pituitary cell populations. These changes are gender specific as pituitary size is increased in males but not females as consequence of treatment.