Endocrine system gonads, have secondary endocrine functions. For example, the kidney secretes endocrine hormones such as erythropoietin and renin. Hormones can consist of either amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins. The endocrine system is in contrast to the exocrine system, which secretes its hormones to the outside of the body using ducts. As opposed to endocrine factors that travel considerably longer distances via the circulatory system, other signaling molecules, such as paracrine factors involved in paracrine signalling diffuse over a relatively short distance. The word "endocrine" derives via New Latin from the Greek words , "endon", "inside, within," and ,
Endocrine disruptor and toddlers ingest more contaminated house dust than the adults they live with, and therefore have much higher levels of pollutants in their systems. Consumer goods are another potential source of exposure to endocrine disruptors. An analysis of the composition of 42 household cleaning and personal care products versus 43 "chemical free" products has been performed. The products contained 55 different chemical compounds: 50 were found in the 42 conventional samples representing 170 product types, while 41 were detected in 43 "chemical free" samples representing 39 product types. Parabens, a class of chemicals that has been associated with reproductive-tract issues,