Faecal oestrogen and progesterone profiles in breeding and non-breeding female North American porcupine (Erethizon dorsaturri)

Abstract

A radioimmunoassay was validated to measure faecal oestrogen and progesterone metabolites in captive female North American porcupines (Erethizon dorsatum) (n = 5) for a period of between 261-393 days. Females housed alone (n = 3) exhibited fluctuations in faecal oestrogens indicative of follicular activity, yet these solitary females did not ovulate spontaneously. Breeding females (n = 2) appeared to experience pscudopregnancy lasting for approximately 87 and 112 days. In the single successful birth, gestation was 135 days. Faecal progestagen concentrations in breeding females were twice that of non-breeding females, however, occasional overlap between pregnant and non-pregnant hormone concentrations precluded the use of faecal steroids as an index of pregnancy status. These preliminary data suggest that noninvasive faecal steroid monitoring is a useful tool for evaluating longitudinal reproductive-endocrine rhythms in porcupines.Resume. -Analyse des fluctuations des taux d'oestrogene et de progesterone fecaux chez des fcmclles reproductrices et non rcproductrices du Pore-epic nord-americain (Erethizon dorsatum). Un dosage par radioimmunologie a etc mis au point dans le but de mesurer les variations de concentrations de metabolites d'ocstrogene et de progesterone chez des femelles captives du Pore-epic nord americain, sur une periode de 261 a 393 jours. Les fluctuations des taux d'ocstrogenes fecaux des femelles maintenues isolees (n = 3) marquent une activite folliculaire, bien que ces femelles solitaires ne presentcnt pas une ovulation spontanee. Les fluctuations d'hormones chez des fcmclles reproductrices (n = 2) suggerent quc ces derniercs presentent une pseudogcstation dont la duree varic de 87 ä 112 jours. Dans le seul cas de mise-bas reussie, la gestation avait dure 135 jours. Les concentrations de progesterone fecale chez les femelles reproductrices etaient deux fois plus importantes que chez les non reproductrices. Toutefois, la superposition occasionnelle cntre les prof us des deux types dc femelles rend difficile utilisation des stero'ides fecaux commc indice de gestation. Ces resultats prcliminaircs suggerent que le suivi non invasif des stero'idcs fecaux peut etre un bon outil devaluation des rythmcs longitudinaux endocriniens de la reproduction chez le Pore-epic nord-americain.

Excretion of Steroid Hormones in Rodents: An Overview on Species Differences for New Biomedical Animal Research Models

“…Few studies on the comparative aspects of steroid metabolism and excretion in cavy-like forms (chinchilla and guinea pig) are available; published data of most reproductive steroids indicate that they are excreted mainly by urine (except for progesterone in chinchilla, see above). Fewer studies are available for sex steroids in this group of rodents; Bogdan and Monfort (2001) evaluated fecal estrogen and progesterone profiles in breeding and non-breeding females of the North American porcupine (Erethizon dorsatum; Erethizontoidae family). For glucocorticoids, cortisol is the main adrenal steroid hormone present in guinea pig plasma (Malinowska and Nathanielsz, 1974).…”