Concentrations of High Density Lipoproteins Vary Among Follicular Sizes in the Bovine

Abstract

This study compared lipoprotein phospholipid, cholesterol, protein, and glycosaminoglycans in the lipoprotein fraction among follicular fluid pools derived from 2633 small (less than 6 mm), 1702 medium (6 to 10 mm), and 491 large (11 to 20 mm) bovine follicles subdivided by estradiol-17 beta concentrations. High density lipoproteins were the only lipoprotein class found in follicular fluid when apolipoprotein profile of the less than 1.21 g/ml density fraction was analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and silver staining. Within a follicular size class, concentrations of lipoprotein constituents did not change among follicular fluid pools with varying estradiol-17 beta concentrations. As follicular size increased, follicular fluid lipoprotein phospholipid, cholesterol, and protein significantly increased. The percentage of total follicular fluid glycosaminoglycans in the less than 1.21 g/ml density fraction was highest for small follicles but averaged less than 5% for all follicular size classes. Therefore, bovine follicular fluid contains only high density lipoproteins and concentrations increased with follicular maturation. That increase in high density lipoprotein could be a potentially important source of cholesterol for progesterone production after the LH surge.

The influence of the corpus luteum on metabolites composition of follicular fluid from different sized follicles and their relationship to serum concentrations in dairy cows

“…This could be associated with the fact that a substantial part of cholesterol content in follicular fluid originates from serum. Cholesterol concentration of FF in CL + and CL − ovaries decreased with the increase in follicular size, which confirms the findings of Thangavel and Nayeem (2004) in buffalo and Huang et al (2002) in pigs but contrast with the study of Leroy et al (2004) in buffalo, Brantmeier et al (1987) in cattle, Nandi et al (2007) in sheep and Thakur et al (2003), Bordoloi et al (2000) and Mishra et al (2003) in the goat. The result of the present study confirmed those of Rahman et al (2008) who reported that low cholesterol concentration in FF indicated biotransformation of cholesterol to steroid hormones.…”

“…Similar to the present result, Leroy et al (2004) in dairy cows and Arshad et al (2005) in buffalos reported that protein concentration was relatively uniform throughout follicular development. However, the current results differ from those of Brantmeier et al (1987) and Wise (1987) in cattle and Thangavel and Nayeem (2004) in buffalos, who reported decrease in total protein concentration with increased follicle size. Albumin plays a vital role in the development of a colloidal pressure which may contribute to high viscosity of follicular fluid.…”

“…Cholesterol is known as a precursor of all steroid hormones including estrogen and progesterone in females . Cholesterol in FF is in the form of a constituent of high-density lipoprotein (Brantmeier et al, 1987) and avascular granulosa cells of the follicles totally depend on the cholesterol from high-density lipoprotein, derived from the blood plasma by crossing the basement membrane of granulosa cells (Mishra et al, 2003). Endresen et al (1990) reported that granulosa cells had a large store of cholesteryl esters that might provide free cholesterol for preovulatory progesterone or steroidogenesis.…”

Use of endometrial cytology and metabolic profiles for selection of embryo donor cows

“…The number and percentage of oocytes were low in the cows under study, which suggests that the presence of cholesterol might improve the capacity of donor cows to produce oocytes that mature and become fertilized. In this respect, components of follicular fluid are known to affect granulose cells and oocyte, as they regulate follicle development and steroidogenesis (Brantmeier et al, 1987). Cholesterol, through HDL and LDL lipoproteins, is the main precursor of steroid hormones (Ramos et al, 2007).…”

Lipid and protein metabolism along with oxidative status of follicular fluidthroughout the estrous cycle in Anatolian water buffalo

“…The Table 1. Classification of the estrous cycle [early I luteal (days 2-3), early II luteal (days 5-6), late luteal (days [15][16][17], and follicular (days [19][20][21] phases] based on the morphological appearance of the corpus luteum (CL), diameter of the follicle (F), and concentration of progesterone (P 4 …”