Vitellogenic

Chakravorty S, Lai B, Singh TP. 1992. Effect of endosulfan (thiodan) on vitellogenesis and its modulation by different hormones in the vitellogenic catfish Clarias batrachus. Toxicology 75 191-198. 

Da Costa, H. and S.M. Ruby. 1984. The effect of sublethal cyanide on vitellogenic parameters in rainbow trout Salmo gairdneri. Arch. Environ. Contam. Toxicol. 13 101-104. 

The olfactory system of the male is extremely sensitive to 17,20jSP. The fish respond to a concentration of 5 x 10 ° mol/1. This amount(3 x 10 molecules) is released by a 90 mm female fish into 1 liter water. The females are also very sensitive to 17,20/3P. It may stimulate ovulation. Of 47 vitellogenic females 13 ovulated when 17,20/3P was added to the water, while only 1 of 43 did so in untreated water (Dulka etal, 1987). Both sexes probably release 17,20/3P. Ecologically, this bisexual pheromone is thought to synchronize milt production with ovulation and thus coordinate spawning in local populations (Dulka etal, 1987 Sorensen and Stacey, 1990). 

The hypothesis that the sex pheromone arises from oxidation of the preformed hydrocarbon was examined by topical application of radiolabeled synthetic 3,11-dimethylnonacosane and the putative intermediate 3,1 l-dimethylnonacosan-2-ol to vitellogenic B. germanica females. Radioactivity from the alkane was detected in... 

These patterns suggest that under normal conditions, feeding in adult females is modulated in a stage-specific manner, regulating the amount of 3,11-dimethylnonacosane that is available for pheromone production. Early in the vitellogenic cycle JH mediates the metabolism of 3,11-dimethylnonacosane to 3,ll-dimethylnonacosan-2-one and other pheromone components. Later in the reproductive cycle, however, the oocytes sequester large amounts of hydrocarbons... 

The rate of syndiesis of soluble proteins (SP) was measured for fat body from decapitated females treated with JHA, CC extracts or both (66). CC extracts do not increase the capacity of the fat body for SP synthesis whereas, JHA has a dose-response effect on SP synthesis. For tissue from females treated with a half-maximal dose of JHA, we found that additional treatment with either a CC extract or Bld-HrTH elevated the rate of SP synthesis to the maximal level observed in normal, vitellogenic females (66) (Figure 5). SDS-PAGE of the SPs demonstrates that the pattern of polypeptides synSiesized depends on JHA and not the presence of CC extracts (66). The latter is also confirmed for synthetic Bld-HrTH. 

The direct effect of an allatostatic ovary-derived factor was first reported in a survey of various tissue extracts of vitellogenic locust females on JH synthesis in vitro (16). We have recently found... 

Figure 3. Inhibition of JH synthesis in vitro by allatotropin-stimulated CA of vitellogenic locusts. - = ovarian extract 0—0 - hemol3nmph extract. Values are the mean of 7-12 replicates.

Biomarkers of effect These comprise measurable biochemical, physiological or other alterations within tissues or body fluids of an organism that can be related to specific causal factors, and can provide information about the magnitude of adverse effects related to those specific causal factors. These include the well-documented cases of the impact of estrogenic compounds in fish where the levels of vitellogens in males act as a biomarker. 

Compound3 Treatment Dose (ug/Adult Females) % Females witt Vitellogenic Eggs ... 

Wood, A.W. and G. Van Der Kraak. Inhibition of apoptosis in vitellogenic ovarian follicles of rainbow trout (Oncorhynchus mykiss) by salmon gonadotropin, epidermal growth factor, and 17/3-estradiol. Mol. Reprod. Dev. 61 511-518, 2002. 

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