PATTERNS OF HORMONE-SECRETION THROUGHOUT PREGNANCY IN THE ONE-HUMPED CAMEL (CAMELUS-DROMEDARIUS)

Peripheral serum samples were collected from 8 pregnant dromedary came ls and hormone secretion patterns were examined at specific time inter vals. Mean serum progesterone concentrations began to rise 3-4 days af ter ovulation and remained reasonably constant at 3-5 ng mL(-1) for th e first 90-100 days of gestation. Concentrations then showed a definit e fall, but thereafter remained constant again at 2-4 ng mL(-1) throug hout the rest of pregnancy. In constrast, serum oestrogen concentratio ns showed pronounced fluctuations during the first 100 days of gestati on. Mean oestradiol-17 beta concentrations increased at around Day 50 to about 100 pg mL(-1) and then remained relatively constant from Day 90 to Day 300. Mean oestrone sulfate concentrations, however, showed t wo definite peaks in early gestation, each reaching about 10 ng mL(-1) , with the first peak occurring around Day 25 and the second peak arou nd Day 75. Oestrogen production then remained fairly constant until ar ound Day 300, after which concentrations of both oestrone sulfate and free oestradiol-17 beta rose steeply over the next 80 days to reach me an peak values of 46 ng mL(-1) and 518.7 pg mL(-1), respectively, at t he time of parturition. Concentrations of 13,14 dihydro-15-keto prosta glandin F-2 alpha (PGFM) remained low and reasonably steady at 100-200 pg mL(-1) during the first 320 days of pregnancy; thereafter, PGFM co ncentrations rose steeply over the next 50 days, before an explosive f urther increase to a peak of 1900+/-141 pg mL(-1) mean+/-sem on the da y of calving. These results suggest that, as in the cow, a major chang e in steroid synthetic capability and/or enzyme content of the placent a may occur at around 80% (Day 300) of gestation in the pregnant camel .