Patterns of hormone secretion throughout pregnancy in the one-humped camel (Camelus dromedarius)

Abstract

Peripheral serum samples were collected from 8 pregnant dromedary camels and hormone secretion patterns were examined at specific time intervals. Mean serum progesterone concentrations began to rise 3-4 days after ovulation and remained reasonably constant at 3-5 ng mL-1 for the first 90-100 days of gestation. Concentrations then showed a definite fall, but thereafter remained constant again at 2-4 ng mL-1 throughout the rest of pregnancy. In contrast, serum oestrogen concentrations showed pronounced fluctuations during the first 100 days of gestation. 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 two definite peaks in early gestation, each reaching about 10 ng mL-1, with the first peak occurring around Day 25 and the second peak around Day 75. Oestrogen production then remained fairly constant until around Day 300, after which concentrations of both oestrone sulfate and free oestradiol-17 beta rose steeply over the next 80 days to reach mean peak values of 46 ng ML-1 and 518.7 pg mL-1, respectively, at the time of parturition. Concentrations of 13,14 dihydro-15-keto prostaglandin F2 alpha (PGFM) remained low and reasonably steady at 100-200 pg mL-1 during the first 320 days of pregnancy; thereafter, PGFM concentrations rose steeply over the next 50 days, before an explosive further increase to a peak of 1900 +/- 141 pg mL-1 mean +/- sem on the day of calving. These results suggest that, as in the cow, a major change in steroid synthetic capability and/or enzyme content of the placenta may occur at around 80% (Day 300) of gestation in the pregnant camel.

Sonographic monitoring of early follicle growth induced by melatonin implants in camels and the subsequent fertility

“…All mated camels ovulated as evident by the plasma progesterone and sonographic appearance of a CL on day 7 and 9 post-mating. Previous studies have shown that the plasma concentrations in mated camels are above 1 ng/ml on day 8 of mating but decreased to less than 1 ng/ml on day 10-11 in the absence of pregnancy [22,32,33]. Sonographic findings and plasma progesterone concentrations were well correlated with each other and in the camel in which the CL disappeared after day 15 of mating the plasma progesterone concentrations also fell.…”

Changes in Expression of Contractile FP and Relaxatory EP2 Receptors in Pregnant Rat Myometrium during Late Gestation, at Labor, and Postpartum1

“…Measurements of PGF 2␣ in the uterine vein of pregnant rats showed that concentrations increased gradually from Day 15, with the highest concentrations around delivery (Day 22) [28]. Interestingly, an explosive increase in PGF 2␣ was also seen in the peripheral plasma of camels just before delivery [29].…”

Actualités sur la reproduction chez la femelle dromadaire (<em>Camelus dromedarius</em>)

“…L'administration de PGF 2 α à n'importe quel stade de la gravidité entraîne l'interruption de cette dernière. Chez la femelle du dromadaire, le placenta ne sécrète pas de progestérone ou n'en produit qu'en quantité insuffisante pour maintenir l'état gravide (41).…”