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PRORENIN AND ACTIVE RENIN CONCENTRATIONS IN OVARIAN FOLLICULAR FLUID INCREASE AFTER THE LH PEAK IN SUPEROVULATED HEIFERS
Author(s) -
Hagemann A.,
Nielsen A. H.,
Assey R. J.,
Hyttel P.,
Boland M. P.,
Roche J. F.,
Poulsen K.
Publication year - 1994
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1994.tb02565.x
Subject(s) - follicular fluid , medicine , follicular phase , endocrinology , luteinizing hormone , estrous cycle , hormone , ovary , biology , chemistry , oocyte , embryo , microbiology and biotechnology
SUMMARY 1. The aim was to analyse the in vivo variations with time of prorenin and active renin and their relationship to steroid hormones in ovarian follicular fluid during follicular growth in heifers. 2. Thirty one beef heifers were assigned to two groups after oestrous synchronization: an unstimulated and a follicle‐stimulating hormone (FSH)‐treated (superovulated) group. Within each group, animals were slaughtered at different times of the follicular phase of the oestrous cycle. Ovarian follicular fluids were aspirated and analysed for the concentrations of active renin, prorenin, oestradiol‐17β (E 2 ) and progesterone (P 4 ). 3. Prorenin and active renin concentrations in follicular fluid remained constant until the luteinizing hormone (LH) peak, after which time they increased four‐ and two‐fold, respectively, in superovulated heifers. 4. In follicular fluid, prorenin and active renin correlated negatively with oestradiol and E 2 /P 4 ratio but positively with progesterone during follicular growth in superovulated heifers. Prorenin also correlated negatively with oestradiol and E 2 /P 4 ratio in unstimulated heifers. 5. The increase of renin concentrations in ovarian follicles after the LH peak and the correlations to steroid hormones suggest an important role of the ovarian renin‐angiotensin system in bovine follicular growth and maturation.