Type

Journal Article

Authors

A.C.O. Evans
J J Ireland
P. Lonergan
J L H Ireland
G W Smith
J Folger
S T Butler
D P Berry
S Walsh
F Jimenez-Krassel
and 1 others

Subjects

Veterinary

Topics
secretion follicle stimulating hormone pharmacology luteinizing hormone analysis of variance cytology drug effects female cell count cattle buserelin cell size animals ovarian follicle radioimmunoassay estradiol pituitary gland anterior blood

Inherent capacity of the pituitary gland to produce gonadotropins is not influenced by the number of ovarian follicles > or = 3 mm in diameter in cattle. (2009)

Abstract We hypothesised that higher serum FSH concentrations in cattle with low v. high follicle numbers during follicular waves are caused by a different capacity of the pituitary gland to produce gonadotropins. Dairy cows with high (> or = 30; n = 5) and low (< or = 15; n = 5) follicle numbers were selected and serum concentrations of oestradiol and FSH during an oestrous cycle were measured. Cows were ovariectomised at oestrus and bled frequently up to 8 days after ovariectomy. After 33 days, cows were injected with gonadotropin-releasing hormone (GnRH) and bled intensively up to 8 h after GnRH injection. One day later, animals were injected with follicular fluid (FF) from bovine follicles and were bled intensively up to 2 days after the first injection. Serum concentrations of FSH and LH were measured. After 2 days, cows were killed and their pituitary glands collected. Prior to ovariectomy, serum oestradiol concentrations were similar between groups, whereas FSH concentrations were higher in cattle with low v. high numbers of follicles. No differences were detected in serum gonadotropin concentrations after ovariectomy, GnRH injection or FF challenge between groups. The results indicate that the inherent capacity of the pituitary gland to secrete gonadotropins does not differ between cattle with high v. low numbers of follicles during follicular waves.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

A.C.O. Evans, J J Ireland, P. Lonergan, J L H Ireland, G W Smith, J Folger, S T Butler, D P Berry, S Walsh, F Jimenez-Krassel and 1 others

Experts in our system

1
A.C.O. Evans
University College Dublin
Total Publications: 92
 
2
P. Lonergan
University College Dublin
Total Publications: 190
 
3
S T Butler
Teagasc
Total Publications: 81
 
4
D P Berry
Teagasc
Total Publications: 215
 
5
S. W. Walsh
University College Dublin
Total Publications: 20