Searchable, peer-reviewed, open-access proceedings from bioscience and biomedical conferences

bp0006rdr4 | Ovarian Function | REDR2006

Control of ovarian follicular development to the gonadotrophin-dependent phase: a 2006 perspective

McNatty KP , Smith P , Heath DA , Juengel IL

In sheep, as in other mammals, ovarian follicular growth is regulated mainly by intraovarian growth factors during early development with pituitary hormones increasingly important during the final phases to ovulation. Most follicles are present as primordial structures and these express many hundreds of genes that fulfil an array of housekeeping and signalling functions. Once growth has been initiated, at least two oocyte-derived growth factors, namely growth differentiation f...

bp0003rdr10 | Development of the Reproductive Axis | REDR1994

Development of the sheep ovary during fetal and early neonatal life and the effect of fecundity genes

McNatty KP , Smith P , Hudson NL , Heath DA , Tisdall DJ , O W-S , Braw-Tal R

In female sheep fetuses, the mesonephros and genital ridge can be identified at days 20 and 23 of gestation (term = 145 days), respectively. Moreover oogonia can be observed at the genital ridge from as early as day 23. Around day 55 of gestation, some germ cells enter meiosis coincident with the arrival of mesonephric-derived somatic cells (i.e. the rete ovarii). From days 75, 100, 120 and 135 of gestation, primordial (one layer of flattened granulosa cells), primary (one...

bp0004rdr1 | Follicular Development | REDR1998

Control of early ovarian follicular development

McNatty KP , Heath DA , Lundy T , Fidler AE , Quirke L , O'Connell A , Smith P , Groome N , Tisdall DJ

Early follicular growth refers to the development of an ovarian follicle from the primordial to early antral phase. In sheep and cows these phases of growth can be classified by the configuration of granulosal cells in the largest cross–section of the follicle as types 1 (primordial), la (transitory) 2 (primary), 3 and 4 (preantral) and 5 (early antral). Follicles classified as type 1 may be highly variable within each species with respect to number of granulosal cells an...

bp0005rdr25 | Genes Controlling Reproductive Performance | REDR2002

Oocyte-derived growth factors and ovulation rate in sheep

McNatty KP , Juengel JL , Wilson T , Galloway SM , Davis GH , Hudson NL , Moeller CL , Cranfield M , Reader KL , Laitinen MPE , Groome NP , Sawyer HR , Ritvos O

The physiological mechanisms controlling ovulation rate in mammals involve a complex exchange of endocrine signals between the pituitary gland and the ovary, and a localized exchange of intraovarian hormones between the oocyte and its adjacent somatic cells. The discoveries in sheep of mutations in bone morphogenetic protein 15 (BMP15) and bone morphogenetic protein receptor type IB (BMPR-IB) together with recent findings on the physiological effects of growth differentiation ...