Influence of follicular maturation on 3-hydroxy-methylglutaryl coenzyme A reductase activity in hen granulosa cells

Abstract

The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase: EC 1.1.1.34) was measured in a microsomal preparation of the granulosa of rapidly growing ovarian follicles of laying hens in the late preovulatory period (2-3 h before expected ovulation). The specific activity of the enzyme was measured in the five largest (F1-F5) preovulatory follicles, F1 being the follicle destined to ovulate first. Enzyme activity increased concomitantly with follicle size. The apparent Km of the enzyme decreased 60-80% from the smallest to the largest preovulatory follicle. There was no significant change in the Vmax during follicle development. Although our results have demonstrated the presence of HMG/CoA reductase in chicken granulosa cells and the progressive increase of its activity with follicular maturation, the quantitative significance of de-novo synthesized cholesterol as steroid hormone precursor remains to be ascertained.

Alternations in Cholesterol and Fatty Acids Composition in Egg Yolk of Rhode Island Red x Fyoumi Hens Fed with Hemp Seeds (Cannabis sativaL.)

“…This competition reduces the absorption rate of the cholesterol by limiting its ability to reach the absorption [27][28][29]. Phytosterols also can lower the hepatic cholesterol biosynthesis by downregulating enzyme activity such as those involved in the terpene synthesis and the 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase, restricting the rate of cholesterol formation [30]. Hence it is inferred that HS lowers egg yolk cholesterol due to its high phytosterol and unsaturated fatty acid contents.…”

A Comprehensive Exploration of the Fatty Acids Profile, Cholesterol, and Tocopherols Levels in Liver from Laying Hens Fed Diets Containing Nonindustrial Hemp Seed

“…Phytosterols mainly β -sitosterol have potential benefits in reducing hypercholesterolemia by blocking cholesterol absorption [ 62 , 63 ]. They can also reduce cholesterol biosynthesis in the liver by modulating the activity of HMG-CoA reductase, thereby limiting the level of cholesterol formation [ 64 ]. Additionally, HS is rich in insoluble fiber and proteins.…”