Patterns of fecal gonadal hormone metabolites in the maned wolf (Chrysocyon brachyurus)

Induction of ovarian activity and ovulation in an induced ovulator, the maned wolf (Chrysocyon brachyurus), using GnRH agonist and recombinant LH

“…Our finding that the presence of a male was required for female maned wolves to ovulate after deslorelin treatment corroborated earlier reports that only paired females naturally ovulate; thus, this species is an induced ovulator [24,34]. Because most canids, with the exception of the island fox [33], ovulate spontaneously (in the absence of a male) [35], being an induced ovulator makes the maned wolf rather unique compared with other species within the family Canidae.…”

“…The reasons for this variation are unknown, but it has been demonstrated that changes in dietary fiber consumption can significantly affect fecal hormone metabolite excretion [42]. When comparing steroid metabolite concentrations observed in the present study to those previously reported by our laboratory [22], the progestagen levels observed in paired females and unpaired individuals injected with reLH were lower than those excreted during the luteal phase in pregnant wolves that gave birth and raised young (mean AE standard error of mean, 68.9 AE 5.9 mg/g feces [24]). …”

“…All females responded to deslorelin by exhibiting an estrogen surge posthormone implant insertion. Concentrations of estrogen metabolites excreted during deslorelin treatment in both paired and singleton individuals were comparable with levels observed during the peri-ovulatory period in naturally cycling females [24]. Thus, a 2.1-mg deslorelin implant was 100% effective at inducing ovarian activity in the maned wolf.…”

“…Estrogen metabolite concentrations of the three females that failed to ovulate were at baseline levels at the onset of deslorelin treatment, whereas estrogens were elevated in the remaining wolf before treatment. Female maned wolves housed individually exhibit a cyclical rise in estrogen concentration throughout the breeding season [24]. Because estrogen is produced by the granulosa cells of growing follicles [32], it is likely that ovarian follicles still grow and produce steroids even in the absence of a male.…”

“…Fecal estrogen and progestagen metabolites were quantified using single antibody enzyme immunoassays, as previously described [24]. Briefly, fecal extracts were diluted in dilution buffer (estrogens, 1:50-1:400; progestagens, 1:500-1:40,000).…”