Abstract
Objectives were to determine the effects of high- and low-density lipoproteins (HDL and LDL) and glycerol on steroidogenesis, insulin-like growth factor-I (IGF- 1) production, and viability of 1) granulosa and theca cells harvested from dominant ovulatory (DO) and non-ovulatory (DNO) follicles during the bovine estrous cycle, 2) mixed luteal cells from corpora lutea (CL) collected on Days 4 and 10 of the estrous cycle, and Day 4 luteal cells from CL destined to be short-lived, and 3) small and enriched large luteal cells from CL collected on Days 4 and 10 of the estrous cycle. Both HDL and LDL maintained a higher (p<0.05) numbers of viable granulosa cells at 72 h of culture and increased the number (p< 0.001) of viable theca cells obtained from DO, but not from DNO follicles. Lipoproteins stimulated (p<0.01) proliferation of steroidogenically inactive theca cells, and HDL maximized (p<0.001) progesterone production by both granulosa and theca cells. Low-density lipoproteins plus glycerol attenuated HDL-stimulated progesterone production. Production of IGF-I by granulosa cells was stimulated (p<0.01) by both HDL and LDL, with HDL being more potent (p<0.001). Low- and high-density lipoproteins stimulated (p < 0.003) progesterone production by bovine luteal cells, and in conjunction with LH stimulated (p<0.05) IGF-I production by luteal cells at 144 h. Lipoproteins stimulated (p<0.01) steroidogenically inactive cell proliferation. High-density lipoprotein maintained higher steroidogenically active cell numbers in luteal cells cultured from Days 4 (p<0.05) and 10 (p<0.09) CL, but not from Day 4 short-lived CL. Progesterone production by large luteal cells cultured from Day 4 and 10 CL, as well as small luteal cells (p<0.05) obtained from Day 10 CL, was stimulated (p<0.01) by HDL and LDL. The combination of LDL and HDL maximized (p<0.01) progesterone secretion in small luteal cells cultured from Day 10 CL. Lipoproteins also enhanced (p<0.05) IGF-I production by small and large luteal cells cultured from Day 4 CL. Lipoproteins stimulated (p<0.001) proliferation of steroidogenenically inactive small cells and maintained (p<0.05) 3j3-HSD-positive cells in large and small cells cultured from both Day 4 and 10 CL. In summary, the lipoprotein environment plays an important role in modulating proliferation and steroidogenesis of bovine ovarian cells.
Bao, Bagna (1994). Lipoprotein utilization by bovine granulosa, theca and luteal cells. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1549691.