Multi-organic endocrine disrupting activity of the UV screen benzophenone 2 (BP2) in ovariectomized adult rats after 5 days treatment.

The chemical industry has developed sun protection factor products, which contain a variety of so-called "UV screens", among others, benzophenones (BP). Based on the structure it can be assumed, that the variant BP2 may be a potent estrogenic endocrine disrupter (ED). Only very limited data are available in the literature about such action of BP2, which focussed on the uterotrophic effect in immature rats. However, determination of ED activity in the uterus is only a restricted approach with the potential risk of missing undesirable actions. Therefore, we examined a putative multiple organ ED activity of BP2 by measuring gene expression of marker genes in the uterus, liver, vagina and pituitary after 5 days oral application in adult ovariectomized (ovx) rats. An effect on lipid metabolism was assessed by determination of cholesterol, high- and low-density lipoproteins (HDL and LDL) in the blood. As control compound, estradiol (E2) was included in the study. A dose dependent E2-agonistic activity was observed in the uterus (increased weight), vagina (increased IGF1 expression), pituitary (reduced LH synthesis), liver (increased IGF1 expression) and lipid parameters (reduction). A non-E2-like action of BP2 was observed on T4- and T3-levels, which were significantly reduced. Except for the action of BP2 on thyroid hormone levels where it may inhibit thyroid peroxidase, this UV screen exerts clear E2-agonistic actions. Application of BP2 for 5 days proved to be a sufficient treatment period to unravel a multi-organic endocrine disrupting activity of this UV screen.