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Cytokine IL-1beta modulation of reproductive function in heat -stressed hens
The effect of heat stress on reproduction is a complex interaction of all systems in the animal body. Because the granulosa cells are the main source for one of the main hormones (progesterone) involved in reproduction, this series of studies was focused on the effect of heat stress on: (1) the ability of granulosa cells to produce progesterone; (2) The involvement of other mediators from other systems in progesterone production under heat stress; (3) Morphology of granulosa cells; (4) The ability of granulosa cells from heat stressed hens to recover over time. Study 1 was conducted to examine the effect of heat stress and cytokine interleukin-1 on the ability of granulosa cells to secrete progesterone. It was found that both heat stress and interleukin-1 significantly reduce the amount of progesterone secreted by chicken granulosa cells. In study 2, the effect of heat stress and interleukin-1 on 3β-hydroxysteroid dehydrogenase (3β-HSD), a key enzyme in progesterone synthesis, was determined. A significant reduction in 3β-HSD activity in response to heat stress and interleukin-1 was observed. Study 3 was conducted to examine the effect of heat stress on granulosa cells morphology, found in earlier studies to be altered. The area covered by lipid droplets in heat stressed hens granulosa cells was significantly greater than that in granulosa cells of thermoneutral hens. In study 4, granulosa cells from heat stressed hens were examined for their ability to recover over time. It was found that these cells have the ability to regain their activity and normal morphology over time, a finding that appears to parallel the systemic return of circulating hormone concentrations during acclimatization long-term heat stress. ^ We conclude that both heat stress and interleukin-1 have the ability to reduce the production of progesterone by granulosa cells, perhaps by reducing 3β-HSD activity. In addition, heat stress alters granulosa cells morphology. However, the effects of heat stress on granulosa cells in terms of enzyme activity, steroidogenesis, and morphology return to near normal over time. ^
Biology, Animal Physiology
Alodan, Mohammed Abdullah, "Cytokine IL-1beta modulation of reproductive function in heat -stressed hens" (2001). ETD collection for University of Nebraska - Lincoln. AAI3028652.