Hormesis: Why it is Important to Toxicology and Toxicologists

Abstract

This article provides a comprehensive review of hormesis, a dose-response concept that is characterized by a low-dose stimulation and a high-dose inhibition. The article traces the historical foundations of hormesis, its quantitative features and mechanistic foundations, and its risk assessment implications. The article indicates that the hormetic dose response is the most fundamental dose response, significantly outcompeting other leading dose-response models in large-scale, head-to-head evaluations. The hormetic dose response is highly generalizable, being independent of biological model, endpoint measured, chemical class, and interindividual variability. Hormesis also provides a framework for the study and assessment of chemical mixtures, incorporating the concept of additivity and synergism. Because the hormetic biphasic dose response represents a general pattern of biological responsiveness, it is expected that it will become progressively more significant within toxicological evaluation and risk assessment practices as well as have numerous biomedical applications.

Coupling bioaccumulation and phytotoxicity to predict copper removal by switchgrass grown hydroponically

“…The phenomenon in which a stimulatory effect may be exhibited with exposure to a low-dose toxicant rather than a high-dose inhibition is generally referred to as hormesis. Calabrese (2008) provided a comprehensive review and indicated that hormetic responses are widely revealed in almost all species, including plants. Although the actual cause is largely unknown, some common features of hormesis have been identified.…”

Hormesis: why it is important to biogerontologists

“…At the mechanism level, there are numerous proximate mechanisms that may account for specific types of biphasic dose responses. The proximate mechanisms may be either ''receptor-or non-receptor'' based (Calabrese 2008a). The consistency of the quantitative features of the hormetic dose responses at the cell, organ and organismic level may be mediating the effects of upstream and highly conserved allometric gene clusters that control and direct the allocation of biological resources within complex biological systems (Calabrese 2011).…”

“…The use of the term hormesis is valuable since it lends specificity to the type of biphasic dose response observed (Calabrese 2008a). …”

“…The format of this review employed a large number of relatively short questions and answers. This format has been followed once before in an article directed toward toxicologists and risk assessors (Calabrese 2008a).…”

Imidacloprid Affects Pardosa Pseudoannulata Adults and Their Unexposed Offspring

“…Hormesis has often been associated with homeopathy, marginalized, and/or ignored; yet it is a very real phenomenon, and is still not fully understood by many (eco)toxicologists (Chapman 2001;Yu et al 2010). Hormetic responses have been reported in hundreds of studies of a broad range of species (protozoa, bacteria, fungi, plants, invertebrates, and vertebrates including humans), biological endpoints (e.g., survival, growth, reproduction), and both inorganic and organic chemicals (Calabrese 2008;Calabrese 2010). There are also many instances of actual hormesis that researchers do not discover because they are not conducting tests with a sufficiently low range of concentrations (Chapman 2001;Calabrese 2008).…”