Study on LH receptor transcripts in buffalo ovarian follicles
Abstract
The present study was carried out on buffalo ovarian follicles. Ovaries were obtained from slaughter house in summer and winter. Follicles present on the ovarian surface were counted and classified as small, medium and large follicles based on their diameter size. The follicles with diameter less than 5 mm were placed under the category of small follicles; those of diameter 5-9 mm were classified as medium follicles, whereas follicles with diameter more than 9 mm were placed under the category of large follicles. These graded follicles were isolated mechanically and looked for the presence of LHr transcript in each season. Each class of follicles was investigated for the presence of Lhr gene transcript in the two seasons using RT-PCR analysis. Further the concentration of LHr cDNa was checked in each category of follicles in the two different seasons using spectrophotometric estimation. The classification of follicles into different categories showed that the presence of higher proportion of small size follicles constituting 80.01% as compared to 16.37% of medium size and 3.6%of large size follicles during winter season. Where as in summer it was 83.28% for small follicles 14.1% of medium size and 8.5% for large sized follicles. The overall average number of follicles present on a single ovary was found to be 8.99 and 9.35 in summer and winter respectively. The average number of small, medium and large follicles was found to be 7.49, 1.27 and 0.23 respectively in summer. There was not much difference in the average count of small and medium follicles per ovary in the winter than that of summer. But there was a significant increase in the average number of large follicles per ovary in winter compared to that of summer season. It was found to be 0.33 in winter. Our study showed the presence of LHr gene transcripts in all the categories of follicles, LHr transcript expresses itself in all follicles irrespective of variation in their diameter size. LHr expression was also found to be continuous irrespective of variation in season that is LHr expression in ovarian follicles was found to be both in summer and winter season. A marked variation was found in the transcript level of LHr gene with increase in follicular size. It was observed that LHr transcript level increases with the increase in follicular size. There was also a notable variation in the transcript level of LHr in summer and winter. It was found that LHr expression decreases in the summer season for the corresponding follicles. This decrease in LHr transcript level during summer may be due to effect of heat stress on LHr expression in ovarian follicles.