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Physiological roles of inhibin in regulation of FSH secretion and follicular development during early pregnancy in goats

Kandiel, Mohamed M.M., Watanabe, Gen, Li, Jun Y., Manabe, Noboru, El Azab, Abd El Salam I., Taya, Kazuyoshi
Domestic animal endocrinology 2008 v.35 no.2 pp. 157-163
nannygoats, pregnancy, ovarian follicles, follicular development, follicle-stimulating hormone, hormone secretion, inhibin, hormonal regulation, estradiol, luteinizing hormone, progesterone
The aim of the current study was to clarify the physiological role of inhibin in controlling FSH secretion and follicular development during the early pregnancy in goats. Eight goats investigated sonographically on Days 19-21 (Day 0=day of mating) for pregnancy were assigned into control (n =3) and treated (n =5) groups. The ovaries of all animals were daily scanned with ultrasound for follicles 2mm or more in diameter from 1 day before to 5 days after treatment. On Day 25 postbreeding; animals received either 10ml, of normal goat serum or antiserum against [Tyr (30)]-inhibin alpha (1-30). Jugular blood samples were collected every 6h starting 24h before and until 120h after treatment. The plasma concentration of FSH increased at 6h and remained at significantly high levels until 120h in treated vs. control group. The plasma concentrations of estradiol showed a marked increased at 66h, with peak levels at 120h after treatment of antiserum. The basal concentrations of LH and the pattern of plasma concentrations of progesterone were not significantly different between the two groups. The number of medium size (3.5-5.0mm) follicles increased considerably from Day 2, whereas small (3.5mm or less) and large (5mm or more) follicles increased noticeably from Day 3, as compared with pre-treatment and controls. These results clearly indicated that inhibin is a key hormone in regulation of follicular development through regulation of endogenous FSH secretion during early pregnancy in goats.