Related Experiment Video
Updated: Apr 7, 2026

A Modified Co-Culture System for Understanding Granulosa-Theca Cell Interactions in the Bovine Ovary
Published on: September 19, 2025
Dynamics of expression and localization of the cannabinoid system in granulosa cells during oocyte nuclear maturation
Ekaitz Agirregoitia1, Inés Ibarra-Lecue2, Lide Totorikaguena3
1Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain; BioCruces Health Research Institute, Barakaldo, Spain.
Objective:
To describe the expression of cannabinoid receptors CB1 and CB2 and cannabinoid-degrading enzymes fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGLL) in human granulosa cells and to investigate their differential distribution with respect to CB1 at various stages during the nuclear maturation of the oocyte.
Design:
Analysis of granulosa cells from germinal vesicle (GV), metaphase I (MI), and MII oocytes by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and indirect immunofluorescence assays.
Setting:
Academic research laboratory.
Patient(S):
Patients from the Human Reproduction Unit of Cruces University Hospital undergoing intracytoplasmic sperm injection.
Intervention(S):
We analyzed the granulosa cells of 300 oocytes from 53 patients. The oocyte maturation stages were 75 at GV stage, 51 at MI, and 174 at MII.
Main Outcome Measure(S):
The mRNA and protein expression of CB1, CB2, FAAH, and MGLL and localization in granulosa cells at each oocyte maturation stage.
Result(S):
CB1, FAAH, and MGLL are present in human granulosa cells during oocyte maturation, but the presence of CB2 receptor is not entirely clear in those cells. CB1 and FAAH were detected in the periphery of the granulosa cells from the GV to the MII oocytes, and they colocalized in some portions of the cell membrane. On the other hand, MGLL immunostaining was more homogeneous across the cell and overlapped with CB1 only weakly.
Conclusion(S):
The presence of the cannabinoid system in granulosa cells suggests a possible role of this system in the nuclear maturation of the oocyte.
Related Concept Videos
Folliculogenesis
Oogenesis
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is...
Oogenesis
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Ovarian Cycle

