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Environmental Modulation of Neuroendocrine Function
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
Richard W. Steger, Andrzej Bartke
Environmental stimuli affecting neuroendocrine function include various signals from parents, siblings, and other individuals within the population. These include pheromones, generally airborne chemosignals that exert a variety of powerful effects on behavior, hormone production, and reproductive processes. The chemical nature and physiological significance of pheromones have been studied extensively in insects and other invertebrates, but there is also a substantial amount of information on pheromonal communication in mammals. In the house mouse (Mus musculus), adult males exert a variety of effects on female reproductive function, including acceleration of pubertal development,343 induction of estrus in adult females (the “Whitten effect”356), and resorption of embryos in females recently inseminated by another male (the “Bruce effect”48). These effects do not require physical contact between the animals and can be produced by exposure of the females to cages or bedding soiled by the males or by placing them “downwind” from cages containing males.46,79,356 There is also evidence that these diverse effects may have a common physiological mechanism; namely, stimulation of gonadotropin release from the female pituitary leading to development of ovarian follicles, increase in estrogen titers, estrus, and ovulation.47 Female mice produce pheromones that delay puberty, suppress estrous cyclicity of other females, and accelerate pubertal development of males.79,341 These effects were discovered in various laboratory strains of house mice, but occur also in wild M. musculus and their laboratory descendants, as well as in other rodent species.30,79 Bronson46 proposed an interesting hypothesis relating these pheromonal effects to ecology and behavior of small rodents in their natural habitat. In some rodent species, high population density stimulates migration in search of new habitats. Under these conditions, pubertal development of “resident” juvenile females would be suppressed by pheromones from adult females, and the young animals migrating from the densely populated area into another territory would be induced to mature and ovulate in response to pheromones from adult males. Clearly, pheromonal control of reproductive development and function can optimize the chances for successful reproduction in short-living animals.
Protective effects of some Nigerian indigenous antimalarial plants on placental malaria related pathological damages and pregnancy outcomes in murine model
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Ayodele S. Babalola, Olufunmilayo A. Idowu, Kehinde O. Ademolu, J. Olukunle, A. Rahman Samson
A method for inducing estrus and proestrus in female mice by exposing them to bedding soaked with male urine (Whitten effect) [22] were used. Sexually mature females (at least 60 days old) were housed for 1 week. Sexually mature male mice (at least 60 days old) were separately housed for 1 week. The females were then exposed for 4 days to bedding soaked with male urine; one male was placed with a pair of naturally synchronized females for a period of 48 h in order to generate timed pregnant females.