6-MBOA affects testis size, but not delayed-type hypersensitivity, in white-footed mice (Peromyscus leucopus)

Abstract

Many rodents use day length to time reproduction to occur when resources are abundant, but some species also use supplementary environmental cues. One supplementary cue is the plant-derived compound, 6-methoxy-2-benzoxazolinone (6-MBOA). Most rodents grow their gonads in response to 6-MBOA in their diets, but it is presently unknown whether they also use 6-MBOA to adjust other aspects of physiology, specifically their immune systems. 6-MBOA is structurally similar to melatonin, and seasonal changes in rodent immune activities are often mediated by melatonin. We therefore predicted that white-footed mice (Peromyscus leucopus), which breed seasonally and are reproductively sensitive to melatonin, would adjust their immune systems when fed 6-MBOA. 6-MBOA treated mice in long day lengths regressed their testes to a greater extent than mice fed a standard diet, or mice kept in short day lengths and fed 6-MBOA or a standard diet. One type of immune activity (delayed-type hypersensitivity) was not affected by 6-MBOA, however, although responses were greater in short versus long day mice. In sum, P. leucopus responded reproductively to 6-MBOA, although differently than other species; immune activity was unaffected. Other aspects of the immune system, especially in herbivorous rodents, may be affected by 6-MBOA and thus warrant further study.

Benzoxazinoids: Cereal phytochemicals with putative therapeutic and health‐protecting properties

“…We recently completed a study in humans showing that a diet high in BXs enhances the TNF-␣ and IL-1␤ production by mononuclear blood cells induced by intact bacteria of the species Porphyromonas gingivalis, and the production of TNF-␣ after stimulation with Escherichia coli LPS (Damgaard et al, manuscript in preparation); indicating an immuneenhancing rather than an anti-inflammatory effect of BXs. In concordance with the findings of Martin et al [90] we observed no effects on T-cell responses.…”

“…In one study [24], immune suppression related to stress was reverted by a MBOA-containing diet. In another study [90], no effect of dietary MBOA was observed.…”

“…The authors claimed that administration of 6-MBOA preserved the cellular immune response in restraint stressed mice. Later, Martin et al [90] studied how various photoperiods influenced DNFBinduced DTH reactions in white-footed mice, and included 6-MBOA in the studies, due to its structural similarity to melatonin, which has been shown to enhance certain aspects of immune activity [91,92]. They found that a dosage of MBOA similar to that of free-living rodents (50 g/g food) had no effect on the DTH responses.…”

“…Shelby et al [24], Martin et al [90] HBOA The free radical scavenging activity of HBOA was tested against 2,2-diphenyl-1-picryl-hydrazyl.…”

Melatonin, But not Auxin, Affects Postnatal Reproductive Development in the Marsh Rice Rat (Oryzomys palustris)

“…Whether this plant-derived melatonin actually alters an animal's physiology, such as its response to changes in photoperiod, awaits further research. Another plant compound, 6-methoxy-2-benzoxazolinone (6-MBOA), is also structurally similar to melatonin and is a reproductive stimulant in some species (Berger et al, 1981;Butterstein et al, 1985;Vaughan et al, 1988;Korn, 1989), but a reproductive inhibitor in other species (Martin et al, 2008). In rice rats, 6-MBOA administration is reported to have no effect on reproduction (Korn, 1989).…”