0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 16 18 20 22 Day of the Estrous Cycle Relative Progesterone Level (Blood)Luteolysis P 4Production (Diestrus) P 4Production (Diestrus) CL Formation (Metestrus) Relative Progesterone Levels (Blood) Follicular Phase Luteal Phase Ovulation Ovulation ?steroid synthesis –progesterone ?collagenase –theca interna ?present 1-3 days following ovulation ? blood vessels in follicle wall rupture ?walls collapse ?cells intermix ?old basement membrane es connective tissue of CL ?increases in size –papilla forms ?composed of cells from the granulosa and theca interna ?progesterone production increases ?a small cavity may be present where the folliclular antrum was present Luteal Tissue Luteal Tissue ?Large cells from granulosa ?Small cells from the theca interna ?Large cells from granulosa ?Small cells from the theca interna Mitochondria Secretory Granules - Oxytocin - Relaxin Functional Capability of CL Functional Capability of CL ?the number of luteal cells –large cells undergo hypertrophy (3 fold) –small cells undergo hyperplasia (5 fold) ?vascularization of CL –Initiated by angiogenic factors from follicle –Vascularity effects CL steroid synthesis and delivery of hormones ?Insufficient CL function –Failure to maintain pregnancy –Important in domestic animals ?the number of luteal cells –large cells undergo hypertrophy (3 fold) –small cells undergo hyperplasia (5 fold) ?vascularization of CL –Initiated by angiogenic factors from follicle –Vascularity effects CL steroid synthesis and delivery of hormones ?Insufficient CL function –Failure to maintain pregnancy –Important in domestic animals Progesterone Targets Aveolar Development Blocks Estrus Negative Feedback Progesterone Production by Luteal Cells
