• Development and Reproduction
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• v.22 no.1
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• pp.55-64
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• 2018

Previous studies showed that recombinant equine chorionic gonadotropin ($rec-eCG{\beta}/{\alpha}$) exhibits both follicle-stimulating hormone (FSH) and luteinizing hormone (LH)-like activities in rat LHR- and FSHR-expressing cells. In this study, we analyzed signal transduction by eelFSHR and eelLHR upon stimulation with $rec-eCG{\beta}/{\alpha}$ and native eCG. The cyclic adenosine monophosphate (cAMP) stimulation in CHO-K1 cells expressing eelLHR was determined upon exposure to different doses (0-1,450 ng/mL) of $rec-eCG{\beta}/{\alpha}$ and native eCG. The $EC_{50$ values of $rec-eCG{\beta}/{\alpha}$ and native eCG were 172.4 and 786.6 ng/mL, respectively. The activity of $rec-eCG{\beta}/{\alpha}$ was higher than that of native eCG. However, signal transduction in the CHO PathHunter Parental cells expressing eelFSHR was not enhanced by stimulation with both agonist $rec-eCG{\beta}/{\alpha}$ and native eCG. We concluded that $rec-eCG{\beta}/{\alpha}$ and native eCG were completely active in cells expressing eelLHR, similar to the activity in the mammalian cells expressing LHRs. However, $rec-eCG{\beta}/{\alpha}$ and native eCG did not invoke any signaling response in the cells expressing eelFSHR. These results suggest that eCG has a potent activity in cells expressing eelLHR. Thus, we also suggest that $rec-eCG{\beta}/{\alpha}$ can induce eel maturation by administering gonadotropic reagents (LH), such as salmon pituitary extract.

• Development and Reproduction
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• v.2 no.2
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• pp.173-178
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• 1998

Leptin, the product of the obese gene, is produced by adipose tissue and is known to be a hormone concerned with regulation of appetite and metabolism. Recent reports have shown that leptin is associated not only with obesity but also with female reproduction, but it has not yet been ascertained whether leptin acts directly on the ovaries or indirectly via the hypothalamus or pituitary pathway. The object of this study is to determine the expression of leptin and its receptor in the ovaries of 3 and 8 weeks old rats by immunohistochemistry and RT-PCR. In the ovaries of 3 and 8 weeks old rats, leptin was stained in the theca cells and portions of granulosa cells of atretic follicles, whereas leptin receptors was stained in interstitial cells and ova of preantral follicles. The RT-PCR results showed that leptin receptor mRNA was expressed in the ovaries of both immature and adult rats, while leptin mRNA was not. In conclusion, leptin mRNA was not expressed in the ovaries, however, leptin was detected by immunohistochemistry. Compared to leptin itself, leptin receptors in the ovaries were ascertained by both RT-PCR and immunohistochemistry. These results suggest that leptin is related to the regulation of the physiological functions of the ovaries.