Monitoring ovarian function and pregnancy in the giant panda (Ailuropoda melanoleuca) by evaluating urinary bioactive FSH and steroid metabolites

Abstract

Urinary excretion of oestrone conjugates, pregnanediol-3 alpha-glucuronide (PdG) and 20 alpha-hydroxypregn-4-en-3-one were measured from 8 weeks before oestrus to 2 weeks post partum and bioactive FSH was monitored during the periovulatory interval in a female giant panda. A biphasic urinary bioactive FSH excretory profile appeared to indicate a broad (approximately 10 day) follicular phase followed by a sharp preovulatory bioactive FSH surge coincident with an acute increase in urinary oestrone conjugates and behavioural oestrus. Weekly concentrations of urinary oestrone conjugates and PdG increased (P less than 0.001) by Week 9 of gestation with 20 alpha-hydroxypregn-4-en-3-one levels increasing 10-30-fold (P less than 0.001) between Weeks 11 and 14. These observations indicate that the monoestrous giant panda does not appear to require a prolonged period of endogenous FSH release or multiple FSH peaks for ovarian priming and follicle selection to proceed normally. Furthermore, the delayed rise in urinary steroid excretion during the second half of gestation in the giant panda supports the concept of delayed implantation while the estimation of steroid conjugates in urine offers a non-invasive approach for monitoring pregnancy status in this endangered species.

Unique biphasic progestagen profile in parturient and non-parturient giant pandas (Ailuropoda melanoleuca) as determined by faecal hormone monitoring

“…This interval was then followed by a distinctive 3-to 20-fold elevation that lasted another 28-63 days before declining to signal birth or the end of a non-parturient phase. A general biphasic progestagen pattern has been reported from earlier urinary monitoring studies of this species, but only in a few individuals (Hodges et al 1984, Chaudhuri et al 1988, Masui et al 1989, Monfort et al 1989, Mainka et al 1990, McGeehan et al 2002, Narushima et al 2003. The present study was important because of the increased confidence generated from simultaneously examining a large cohort of giant pandas, some of which were observed year to year.…”

“…Although peak in urinary progestagens coincides with ultrasonographic foetus detection in giant pandas (Zhang et al 2009), it is unknown whether nidation occurs with the onset of a secondary progesterone (P 4 ) rise, as has been demonstrated in the mink (Mustela vison; Allais & Martinet 1978) Schwarzenberger et al 2004). A similar prolongation of progestagen excretion occurs in the giant panda, although this method is uninformative in diagnosing pregnancy (Monfort et al 1989, Steinman et al 2006.…”

“…There has been little attention directed at understanding the prolonged luteal phase in pregnant versus non-pregnant individuals. Of ten reports on this topic, only three giant pandas in total have been monitored for urinary progestagen profiles from ovulation to parturition or through a non-parturient phase (sometimes referred to as 'pseudopregnancy'; Bonney et al 1982, Hodges et al 1984, Chaudhuri et al 1988, Masui et al 1989, Monfort et al 1989, McGeehan et al 2002, Narushima et al 2003, Dehnhard et al 2006, Steinman et al 2006, Spady et al 2007. In these cases, a secondary urinary progestagen rise has occurred 74-122 days after the end of oestrus (Steinman et al 2006) that has suggested a shift in hormonal source, perhaps related to nidation.…”

“…In these cases, a secondary urinary progestagen rise has occurred 74-122 days after the end of oestrus (Steinman et al 2006) that has suggested a shift in hormonal source, perhaps related to nidation. The giant panda has long been considered to experience delayed implantation (Hodges et al 1984, Monfort et al 1989, Zhang et al 2009), a strictly mammalian strategy prominent in carnivores, especially ursids (Hamlett 1935, Conaway 1971, Weir & Rowlands 1973, Renfree & Calaby 1981, Mead 1989, Sandell 1990, Lindenfors et al 2003, Spady et al 2007. After fertilization, the embryo is sustained as a blastocyst until an unidentified trigger stimulates implantation and resumption of development (Renfree & Calaby 1981, Mead 1989, Sandell 1990).…”

Reproductive endocrinology of zoo-housed aardwolves

“…In non-seasonal breeders, females exhibit ovulatory cycles and males are typically reproductively active throughout the year (Brown 2006). Contrarily, in seasonally breeding species reproductive hormones are elevated but highly variable during a defined period of time in both males and females (Monfort et al 1989;Wingfield 1990;Monfort et al 1997;Kraaijeveld-Smit et al 2002;Kretzschmar et al 2004;Hesterman et al 2005; Dloniak et al 2006b; Fanson et al 2010a, b). The ultimate causes for seasonal breeding strategies are linked to temporal variation in resource abundance, whereas the most important proximate regulator of reproductive activity is photoperiod (Scott 1986; Goldman 1999), typically with the relative rate of change in daylight patterns being more important than the photoperiod per se (McAllan and Dickman 1985).…”