Endocrine regulation of the reproduction in crustaceans: Identification of potential targets for toxicants and environmental contaminants

Abstract

Progress in ecotoxicological research documents that crustaceans are highly vulnerable to diverse chemicals and toxicants in the environment. In particular, pollutants affecting endocrine homeostasis in crustaceans (i.e., endocrine disruptors) are intensively studied, and serious reproductive disorders have been documented. In this review, current knowledge about the endocrine regulation of the crustacean reproduction is put together with the published ecotoxicological data with an attempt to summarize the potential of xenobiotics to affect crustacean reproduction. Following gaps and trends were identified: (1) Studies are required in the field of neurohormone (serotonin and dopamine) regulation of the reproduction and possible modulations by environmental toxicants such as antidepressant drugs. (2) Molting-related parameters (regulated by ecdysteroid hormones) are closely coordinated with the development and reproduction cycles in crustaceans (cross-links with methyl farnesoate signalling), and their susceptibility to toxicants should be studied. (3) Other biochemical targets for xenobiotics were recently discovered in crustaceans and these should be explored by further ecotoxicological studies (e.g., new information about ecdysteroid receptor molecular biology). (4) Some sex steroid hormones known from vertebrates (testosterone, progesterone) have been reported in crustaceans but knowledge about their targets (crustacean steroid receptors) and signalling is still limited. (5) Determination of the sex in developing juveniles (affecting the sex ratio in population) is a sensitive parameter to various xenobiotics (including endocrine disruptors) but its modulation by general environmental stress and non-specific toxicity should be further studied.

Reproductive regulators in decapod crustaceans: an overview

“…Environmental variables such as salinity, temperature and seasonality play vital roles in regulating crustacean physiology, including reproduction, behavior, molting, morphogenesis and feeding (Charmantier-Daures et al, 1994;Fingerman, 1997a;Mazurová et al, 2008;Spanings-Pierrot et al, 2000). We observed that when red phase crabs were transferred into diluted seawater, the percentage of MF increased to nearly 100% at 11°C and 18°C (Nagaraju and Borst, 2008).…”

“…Alternative techniques have been attempted to stimulate ovarian development, such as administration of gonad inhibitory hormone (GIH) antibody, hormonal level changes by environmental factors such as temperature, salinity and photoperiod, precise functionality of neurotransmitters and double-stranded RNA interference (dsRNAi) to reduce gonad inhibitory peptide transcript. The results from these experiments have revealed the potential (Chang et al, 2001;FanjulMoles, 2006;Mazurová et al, 2008;Nagaraju, 2007;Nagaraju and Borst, 2008;Treerattrakool et al, 2008) to stimulate gonad maturity. So, in this context, I will discuss up-to-date research on gonad regulatory factors and their role in reproductive development.…”

“…A number of hormones from neuroendocrine organs play an essential role in controlling gonad maturation (Chang et al, 2001;Fingerman, 1997a;Laufer et al, 1993a;Mazurová et al, 2008;Nagaraju, 2007;Raviv et al, 2008). Gonad maturation in crustaceans appears to be regulated by two antagonistic neuropeptides: GIH (also called vitellogenesis inhibiting hormone, VIH, in females) synthesized and secreted from the X-organ-sinus gland (XO-SG) complex of the eyestalk ( Fig.2A and Table1), and gonad stimulating factor (GSF), thought to be produced by the brain and thoracic ganglion (Fig.2B,C,F, Table1) (Eastman-Reks and Fingerman, 1984;Otsu, 1963).…”

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

“…Chem. 30,2011removal or effects from transplantation or from the addition of organ homogenates (for reviews, see [81][82][83]). Information concerning these neuropeptides has been accumulating from many species, although the number of these neuropeptides in a single species is still uncertain [76].…”

Vitellogenin and vitellogenin receptor gene expression and 20-hydroxyecdysone concentration in Macrobrachium rosenbergii exposed to chlordecone

“…Indeed, in crustaceans, serotonin is identified as a neurotransmitter that stimulates release of some neurohormones such as crustacean hyperglycemic hormone (CHH) or MIH (Keller and Beyer 1968;Mattson and Spaziani 1985) and inhibits the release of GIH (Kulkarni and Glade 1991;Tinikul et al 2008). Processes regulated by serotonin may become a target for environmentally relevant endocrine disruptors, such as insecticides because of their neurotoxic properties (Brooks et al 2003;Henry et al 2004;Mazurová et al 2008). The assumption on the serotonin involvement in the Vg and VgR gene expressions is supported by the fact that Ruttanakorn et al (2014) observed an increase of the Vg concentration in M. rosenbergii, after serotonin injection.…”