Bioscientifica Proceedings

Abstract unavailableKeywords: sheep; ovulation rate; nutrition; gonadotrophins; metabolic hormones© 1991 Journals of Reproduction & Fertility Ltd...

The development of antral follicles in sheep and cattle is dependent on FSH, but large antral follicles can shift their gonadotrophic dependence from FSH to LH. The mechanisms that result in the selection of at least one ovulatory follicle from identical follicular cohorts, exposed to the same endocrine environment, still remain to be elucidated. The aim of this research was to extend in vitro results from the rodent to sheep and cattle and, using both in vivo</em...

Abstract unavailableKeywords: inhibin; activin; follistatin. αN peptide; ovary; follicle; corpus luteum© 1991 Journals of Reproduction & Fertility Ltd...

In the mammalian ovary there is considerable and continuous remodelling of tissue during both fetal and adult life, necessitating changes in extracellular matrix. Matrix is a diverse group of molecules varying in its composition and roles, which include regulation of growth factor activity and cell behaviour. Here we discuss four topical aspects of matrices in ovaries. (1) Our current state of knowledge of latent TGFß binding proteins that can bind the extracellular matri...

The cellular biology and changes in the extracellular matrix of ovarian follicles during their development are reviewed. During growth of the bovine ovarian follicle the follicular basal lamina doubles 19 times in surface area. It changes in composition, having collagen IV α1–26 and laminin α1, ß2 and γl at the primordial stage, and collagen IV α1 and α2, reduced amounts of α3–α5, and a higher content of laminin α1, ß...

Experiments were conducted to further our understanding of the cellular and molecular mechanisms that regulate luteal function in ewes. Inhibition of protein kinase A (PKA) reduced (P < 0.05) secretion of progesterone from both small and large steroidogenic luteal cells. In addition, the relative phosphorylation state of steriodogenic acute regulatory protein (StAR) was more than twice as high (P&hairsp;<&hairsp;0.05) in large vs small luteal cells. Large steroidogenic...