Granulosa cell tumour in a llama (Lama glama).

Hormonally active tumours are characterized by production and secretion of hormones, irrespective of endogenous feedback mechanisms. An adult llama had exuberant oestrous behaviour, infertility, elevated concentrations of oestradiol and a large ovarian mass. Necropsy revealed the presence of two large abdominal masses, one effacing the right ovary and one in the mesocolon. Considering the clinical and histopathological findings, we conclude that the llama was affected by a granulosa cell tumour. The case suggests that granulosa cell tumours in camelids are hormonally active, and the clinical presentation resembles that of other large animal species. To our knowledge, this is the first case report of an oestrogen-producing, metastatic granulosa cell tumour in a llama.

Kisspeptin induces LH release and ovulation in an induced ovulator†.

Kisspeptin has been implicated in the ovulatory process of several species of spontaneous ovulators but in only one induced ovulator. In contrast, NGF in semen is the principal trigger of ovulation in other species of induced ovulators-camelids. We tested the hypotheses that kisspeptin induces luteinizing hormone (LH) secretion in llamas through a hypothalamic mechanism, and kisspeptin neurons are the target of NGF in its ovulation-inducing pathway. In Experiment 1, llamas were given either NGF, kisspeptin, or saline intravenously, and LH secretion and ovulation were compared among groups. All llamas treated with NGF (5/5) or kisspeptin (5/5) had an elevation of LH blood concentrations after treatment and ovulated, whereas none of the saline group did (0/5). In Experiment 2, llamas were either pretreated with a gonadotropin-releasing hormone (GnRH) receptor antagonist or saline and treated 2 h later with kisspeptin. Llamas pretreated with saline had elevated plasma LH concentrations and ovulated (6/6) whereas llamas pretreated with cetrorelix did not (0/6). In Experiment 3, we evaluated the hypothalamic kisspeptin-GnRH neuronal network by immunohistochemistry. Kisspeptin neurons were detected in the arcuate nucleus, the preoptic area, and the anterior hypothalamus, establishing synaptic contacts with GnRH neurons. We found no colocalization between kisspeptin and NGF receptors by double immunofluorescence. Functional and morphological findings support the concept that kisspeptin is a mediator of the LH secretory pathway in llamas; however, the role of kisspeptins in the NGF ovulation-inducing pathway in camelids remains unclear since NGF receptors were not detected in kisspeptin neurons in the hypothalamus.