|Budget Amount *help
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2000: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥9,400,000 (Direct Cost: ¥9,400,000)
The intra-luteal regulators consist of peptides, eicosanoids, growth factors, cytokines, and neurotransmitters. In the present studies, the roles of locally produced substances in the control of luteal function were demonstrated. The results obtained in this project lead us to the following conclusions:
Luteal progesterone (P4), oxytocin (OT) and PGs produced locally are components of an autocrine/paracrine positive feedback cascade in bovine early to mid-cycle CL, and responsible for the resistance of the early bovine CL to the exogenous PGF2α action.
The presence of functional TNFα receptors was determined not only on the bovine luteal cells obtained cyclic CL and CL of pregnancy, but also on the microvascular endothelial cells derived from developing bovine CL by binding analysis and PCR analyses. Therefore, TNFα may play some roles in regulating bovine CL function throughout the estrous cycle and pregnancy.
LH plays a role in the regulation and maintenance of bovine CL function during
pregnancy as well as during the estrous cycle, and the effect of LH on CL function depends on the concentration, but not the affinity, of LH receptors.
Adrenergic and nitrergic agents may play opposite roles in the regulation of bovine CL functions. Whereas NA may play a supporting role in luteal development, NO may participate in the functional regression of the bovine CL by inhibiting steroidogenesis.
Estradiol is produced locally in bovine CL throughout the estrous cycle, and estradiol plays a role in regulating PGF2α production in CL as an autocrine/paracrine factor.
Endogenous lipoxygenase products plays important roles in P4 production by bovine CL, i. e. basal P4 production is supported by 12-HETE, and LH-stimulated P4 production is partially mediated via the activation of lipoxygenase and subsequent 15-HETE formation downstream of the LH-activated cAMP-PKA- phosphorylation pathway.
A Fas/Fas L system is present in bovine CL, and leukocyte-derived cytokines play important roles in Fas-mediated luteal cell death. Less