Bioscientifica Proceedings

Summary. This review analyses the endocrine recognition of pregnancy in the sheep. Particular emphasis is placed on the effect of a blastocyst on prostaglandin and protein metabolism in the endometrium. The preimplantation period is associated with increased prostaglandin content in the endometrium and uterine lumen, increased leucine incorporation into endometrial protein and increased blood flow to the uterus. It is concluded that there are substantial alter...

Summary. Primary cultures of ovine epithelial and stromal cells have been used to examine paracrine interactions between the endometrium and the preimplantation sheep blastocyst, and in particular the actions of the blastocyst α-interferon, ovine trophoblast protein-1 (oTP-1), on endometrial cell metabolism. The synthesis and secretion of several ‘pregnancy-related’ acidic proteins with molecular weights in the range 70 000–120 000 can be i...

Summary. The relationship between the pituitary gland and testis in rams was studied from birth to sexual maturity. The concentrations of LH, FSH and testosterone increased between 5 and 7 weeks of age; the rise was not correlated with any specific cytological change in the testis. An augmented pituitary response to LH-RH was demonstrated as levels of gonadotrophin increased. It is unclear whether this change in sensitivity plays a role in initiation of the pu...

Abstract unavailableKeywords: inhibin; male; reproduction; gonadotrophins; FSH© 1991 Journals of Reproduction & Fertility Ltd...

Unlike in sheep, in which immunization against androstenedione causes mild and reasonably controlled increased ovulation rate, in similar studies cattle showed highly variable responses ranging from increased ovulation rate and fertility through to anovulation/anoestrus or superovulation. As a consequence, interest in manipulation of ovulation rate through this approach has declined and is now focused on immunological manipulation of endogenous inhibin following successful stu...

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