Mouse Whitten Effect

The male mouse produces a scent in his urine which induces and accelerates the estrus cycles of the female. This effect will be greater in females in which estrus was suppressed by aggregation. According to Nichols and Chevin (373), male urine is less effective than male presence in inducing the estrus cycle, while Gangrade and Dominic s (341) studies suggested that in contrast to the Bruce effect, the pheromone involved in the Whitten effect is a volatile substance. 

Recently Jemiolo et al. (351), observed that two volatile constituents of male mouse urine, 2-(5 c-butyl)-4,5-dihydrothiazole (67) and 3,4-de-hydro-exo-brevicomin (65), which is also involved in promoting aggressive behavior in males, when added in appropriate concentration were found to be as effective as normal urine in inducing the Whitten effect. 

Although, as previously noted, Cholewa and Whitten (1970) reported the culture of preimplantation stages of mammalian embryos in the absence of protein, these same workers noted that bovine serum albumin had a beneficial effect in that 1-cell mouse embryos will cleave more readily and the hatching of later stages appeared facilitated by this protein. Furthermore, most culture media used for mammalian embryos have contained some source of protein. Nevertheless, only a few studies have been reported in which various protein sources have been compared and these studies have been limited to nonprotein substitutes, sera from various animals, and uterine protein fractions. 

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