• The Korean Journal of Zoology
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• v.31 no.2
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• pp.81-86
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• 1988

The relationship between cumulus cell expansion, cocyte maturation and metabolic cooperativitiy was investigated by using mouse and pig cocyte-cumulus complexes in vitro. Cocyte germinal vesicle breakdown (GVBD) and cumulus expansion were manipulated with hormones or reagents which increase intracellular cAMP leveL Metabolic cooperativity between oocyte and cumulus cells was assessed by determination of the fraction of radiolabelled uridine marker that was transferred from the cumulus mass to the oocyte. Uptake of uddine marker by mouse and pig cumulus mass was increased by about fourfold of basal level with the stimulation of hormones (human choriononic gonadotrophin, HCG; follicle stimulating hormone, FSH) or cyclic AMP sttmulators (3-isobutyl-1-methylxanthine, IBMX; forskolin) during culture. However, the fraction of uridine that was transferred from the cumulus mass to the cocyte (transfer ratio) was gradually decreased during culture, irrespective with the presence of hormones or stimulators. The decrease of the transfer ratio was not correlated with the state of occyte whether they have GV or not, or with the degree of cumulus expansion. In mouse complexes, HCG induced more significant reducton of transfer ratio than other treatments. These results do not support the idea that modulations of metabolic cooperativity between cumulus cells and oocytes are important for the regulation of meiotic resumption in mammals.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.11a
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• pp.57-64
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• 2007

Metabolic interactions of the three major cannabinoids, ${\Delta}^9$-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) with steroid hormones were investigated. These cannabioids concentration-dependently inhibited $3{\beta}$-hydroxysteroid dehydrogenase and $17{\alpha}$-hydroxylase in rat adrenal and testis microsomes. CBD and CBN were the most potent inhibitors of $3{\beta}$-phydroxysteroid dehydrogenase and progesterone $17{\alpha}$-hydroxylase, respectively, in rat testis microsomes. Three cannabinoids highly attenuated hCG-stimulated testosterone production in rat testicular interstitial cells. These cannabinoids also decreased in levels of mRNA and protein of StAR in the rat testis cells. These results indicate that the cannabinoids could interact with steroid hormones, and exert their modulatory effects on endocrine and testicular functions. Metabolic interaction of a THC metabolite, $7{\beta}$-hydroxy-${\Delta}^8$-THC with steroids is also investigated. Monkey liver microsomes catalyzed the stereoselective oxidation of $7{\beta}$-hydroxy-${\Delta}^8$-THC to 7-oxo-${\Delta}^8$-THC, so-called microsomal alcohol oxygenase (MALCO). The reaction is catalyzed by CYP3A8 in the monkey liver microsomes, and required NADH as well as NADPH as an efficient cofactor, and its activity is stimulated by some steroids such as testosterone and progesterone. Kinetic analyses revealed that MALCO-catalyze reaction showed positive cooperativity. In order to explain the metabolic interaction between the cannabinoid metabolite and testosterone, we propose a novel kinetic model involving at least three binding sites for mechanism of the metabolic interactions.