Circulatory cholesterol as an important source of substrate for piscine ovarian steroidogenesis
Deb, S.; Bhattacharya, S.
Indian Journal of Experimental Biology 24(2): 71-76
1986
ISSN/ISBN: 0019-5189 PMID: 3733168 Document Number: 282755
In female freshwater perch, Anabas testudineus, non-esterified cholesterol of plasma and ovary altered seasonally whereas esterified cholesterol remained unchanged. [4-14C]-cholesterol was used as a tracer to study the interrelationship between plasma and ovarian cholesterol. After intramuscular injection, radiolabeled cholesterol in plasma was highest at 6 hr followed by gradual fall while in the ovary incorporation of radiolabeled cholesterol started increasing from 6 hr and reached its peak at 18 hr. Out of the total radioactivity recorded at 18 hr, 23% was accounted for pregnenolone and 17% for progesterone and rest 60% remained unconverted. Mobilization pattern of plasma cholesterol into the ovary was different at different stages of reproductive cycle; during preparatory and prespawning stage the drop in plasma radiolabeled cholesterol and its consequent rise in the ovary were found to be remarkably pronounced than what was observed in the fish belonging to spawning and postspawning stage. Ovine LH and SG-G100 (1 .mu.g/100 g body weight) resulted significant depletion of both plasma and ovarian cholesterol. Such depletory effect was not observed with ovine FSH. Aminoglutethimide, a drug which inhibits mitochondrial steroidogenesis, blocked the depletory effect of SG-G100 on plasma and ovarian cholesterol, indicating the depletion of plasma cholesterol is indeed a reflection of increased ovarian steroidgenesis.