The plant metabolite 6-methoxybenzoxazolinone interacts with follicle-stimulating hormone to enhance ovarian growth.

6-Methoxybenzoxazolinone (6-MBOA) is a novel plant metabolite that enhances reproductive status in vertebrate consumers while it inhibits insect, fungal, and bacterial infestation of the plant. Ovaries of prepubertal rats show a dose response to increasing amounts of 6-MBOA.administered in Silastic capsule implants. Ovaries increased in size in response to capsules with 0.5-3.0 cm exposed surface area of 6-MBOA, whereas larger capsules (6 cm 6-MBOA) had no effect. Removal of the pituitary in both prepubertal and mature rats eliminated the stimulatory influence of 6-MBOA. In hypophysectomized animals treated with diethylstibestrol implants, 6-MBOA did not affect ovarian weight and no animals ovulated. Administration of follicle-stimulating hormone (FSH) increased ovarian weight and stimulated production of ova, and FSH combined with 6-MBOA resulted in larger ovaries that released more ova. 6-MBOA also enhanced ovarian growth in intact prepubertal animals treated with pregnant mare's serum gonadotropin. These results show that 6-MBOA has the ability to interact with FSH to stimulate follicular development and increase ovulation. Non-steroidal plant compounds may have a significant impact on the reproductive patterns of wild animal populations.

The plant metabolite, 6-methoxybenzoxazolinone, stimulates an increase in secretion of follicle-stimulating hormone and size of reproductive organs in Microtus pinetorum.

The plant metabolite, 6-methoxybenzoxazolinone (6-MBOA), occurring in leaf tissue of rapidly growing monocots, cues reproduction in some mammals. In the pine vole, Microtus pinetorum, peripubertal females respond to this nonestrogenic compound with a 40% increase in serum levels of follicle-stimulating hormone (FSH). In addition, 6-MBOA significantly increases the weight of the ovary and uterus in both peripubertal and mature voles. This study is the first to offer evidence that 6-MBOA interacts with the pituitary to stimulate reproduction in voles.

A naturally occurring plant compound, 6-methoxybenzoxazolinone, stimulates reproductive responses in rats.

A nonestrogenic component of young, rapidly growing plants, 6-methoxybenzoxazolinone (6-MBOA), was examined to determine its effect on the reproductive responses of prepubertal and mature female rats. Prepubertal animals treated with a single injection of 6-MBOA or with Silastic capsules implanted for 3 days showed a significant increase in both ovarian and uterine weight. Serum luteinizing hormone was unaffected by 6-MBOA treatment for 3 days in 32-day-old animals, whereas serum follicle-stimulating hormone was elevated. Silastic capsule treatment of mature animals showed the following results. Extended treatment for 6 estrous cycles had no influence on the timing of vaginal cyclicity; despite this, 6-MBOA treatment for 2 cycles caused an increase in ovarian weight resulting from an increase in the number of corpora lutea per ovary. Animals treated for 1 cycle showed a significant increase in the number of ova shed. Uterine weight in mature animals did not increase. This study indicates that 6-MBOA has a stimulatory effect on the reproductive system of young and mature female rats. It is the first attempt to relate the effects of the compound on the endocrine system of any animal. That nonestrogenic plant compounds can trigger reproduction has important ecologic and physiologic significance.

Male siblings inhibit reproductive activity in female pine voles, Microtus pinetorum.

Pine vole females paired in breeding cages with male siblings remain unreproductive beyond the age of puberty onset. In this study only 10% of females caged with their brothers reproduced, whereas 85% of females placed with strange males had litters. Mating between a female and a strange male was also suppressed by the presence of a male sibling sequestered behind a wire mesh barrier in the breeding cage. When the sibling male was removed from the cage after 1 day, 78% of the females produced litters. When the sibling remained behind the barrier in the breeding cage, only 42% gave birth to young conceived in his presence. Conception of second litters during the postpartum estrus occurred in over 80% of females caged with strange males alone and only 10% of females caged with sibling males. Female pine voles are induced to become reproductively active by strange males but this activity is depressed by the presence of a brother, and once initiated it does not continue if the female is caged with her brother.