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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.48 [2010] >
IJEB Vol.48(06) [June 2010] >
| Title: | Inhibition of hCG-induced spawning by a-methylparatyrosine, a tyrosine hydroxylase inhibitor, in the catfish Heteropneustes fossilis (Bloch) |
| Authors: | Chaube, R
Joy, K P |
| Keywords: | Human Chorionic Gonadotropin
 -Methylparatyrosine
Ovulation
Spawning
Tyrosine hydroxylase |
| Issue Date: | Jun-2010 |
| Publisher: | CSIR |
| Abstract: | In this study, the effect of pharmacological inhibition
of catecholaminergic activity on hCG-induced spawning was evaluated and
correlated with tyrosine hydroxylase (TH) activity, the rate-limiting enzyme in
catecholamine biosynthesis. Gravid female H. fossilis collected in both
prespawning and spawning phases were given -methylparatyrosine (-MPT: 250 g/g body
weight, ip, an irreversible inhibitor of TH) and human chorionic gonadotropin
(hCG: 100 IU/fish, ip) alone or in combination. The fish were sampled at
different intervals for measuring hypothalamic and ovarian TH activity and
checking spawning response. The administration of hCG resulted in ovulation and
spawning in both phases with a higher response in the spawning phase. The
administration of -MPT did not induce any response, like the control
fish. In the
hCG + -MPT groups, the spawning response of hCG was
significantly inhibited and delayed by the inhibitor. The spawning response of
hCG was accompanied by a significant increase in both hypothalamic and ovarian
TH activity at
6 and 12 h of the injection. However, at 24hr the activity decreased except in
the spawning phase. The -MPT treatment inhibited TH activity
significantly in a duration–dependent manner. In the hCG + -MPT groups,
enzyme activity was inhibited at all duration. The results indicate the
involvement of catecholamines during the hCG-induced spawning and the specific
functional nature of the involvement needs further investigation. |
| Page(s): | 549-553 |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.48(06) [June 2010]
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