Noninvasive monitoring of ovarian endocrine activity in the chinchilla (Chinchilla lanigera).

BUSSO JM; PONZIO MF; FIOL DE CUNEO MH; RUIZ RD

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2007 vol. 150 p. 288 - 297

0016-6480

Reproductive endocrinology information is limited for Chinchilla lanigera, a South American species characterized by extremely long gestation and estrus cycle compared with others rodents. This study was designed to validate a non-invasive technique for monitoring ovarian endocrine activity. Animals were exposed indoors to natural photoperiod (31°S–64°W, Argentina); temperature range: 17–26 °C, with food and water ad libitum. Radiolabelled infusion (nD4): 3H-estradiol (3H-E2) and 14C- progesterone (14C-P4) were injected (i.p). Biochemical validation: HPLC-UV detector was employed to determine natural steroids in urine and fecal extracts and to determine immunoreactive metabolites. Physiological validation: (1) pregnancy (nD5): body weight and urinary and fecal steroidal metabolites were measured until birth; (2) Seasonality (nD9): urine and feces were collected in May, August, November, and February. Total 3H-E2 and 14C-P4 radioactivity recovered was 60.5§15.5 and 74.5§19.4%, respectively. After 3H-E2 injection, urinary radioactivity peaked at 7.0§0.6 hr; in contrast, urinary 14C-P4 excretion peaked at 44.0§4.0 hr (pD0.000). Peak radioactivity in feces occurred between 24–48 hr for both hormones. Several correlations were detected during pregnancy between body weight vs. urinary progestagens/day (rD0.44, p <0.03); vs. urinary progestagens/creatinine (rD0.73, pD2.9£10¡5); vs. urinary estrogens/day (rD0.74; p<0.2); and vs. urinary estrogens/ creatinine (rD0.74; p<2.0£10¡5). On the other hand, urinary and fecal progestagen excretion exhibited signiWcant seasonal Xuctuations and urinary estrogen concentrations showed a similar pattern (pD0.062 for winter–spring vs. summer–autumn). This methodology proved to be useful for monitoring ovary endocrine activity in urine of chinchilla female. © 2006 Elsevier Inc. All rights reserved.