In vitro effects of gonadotropin-releasing hormone (GnRH) on Leydig cells of adult alpaca (Lama pacos) testis: GnRH receptor immunolocalization, testosterone and prostaglandin synthesis, and cyclooxygenase activities

Using PGFM (13,14-dihydro-15-keto-prostaglandin F2α) as a non-invasive pregnancy marker for felids

“…Also, it should be considered that PGF 2␣ could affect steroid biosynthesis. It has been shown that PGF 2␣ is involved in the up-regulation of steroid biosynthesis in alpaca Leydig cells [35] and also inhibits the release of progesterone in caprine luteal tissues [36]. This action on luteal cell steroid production could also occur in felids, which may explain the gradual decline in peripheral progesterone concentrations in the cat during the last pregnancy weeks-a decrease which does not appear compensated by the placenta [37].…”

Innervation and Immunohistochemical Characteristics of Epididymis in Alpaca Camelid (Vicugna Pacos)

“…Wang et al (2011) reported that NGF is espressed in the testis of alpaca . In addition, it has been demonstrated that GnRH directly up-regulates testosterone production in Leydig cells with a postreceptorial mechanism that involves phospholipase C, COX1 and PGF2 (Zerani et al, 2011). Recently, moreover, it has been postulated that orexin and its receptor 1 are involved in the regulation of steroidogenesis in the alpaca testis (Liguori et al, 2012).…”

Immunopresence and functional activity of prostaglandin-endoperoxide synthases and nitric oxide synthases in bovine corpora lutea during diestrus

“…Nitric oxide (NO) is an intracellular messenger that is present in male and female reproductive organs of various mammalian species [4,8,9,18,19]. NO is synthesized from its precursor L-arginine by the action of NO synthase (NOS), which exists in three isoforms: calcium/calmodulin-dependent constitutive isoforms (endothelial, eNOS, and neuronal, nNOS), and calcium/calmodulin-independent inducible isoform (iNOS) [8].…”