Endocrine correlates of reproduction in the wolf. I. Serum progesterone, estradiol and LH during the estrous cycle
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Abstract
The estrous cycle of 10 intact female wolves, aged 8 months-8 years at the initiation of the study, was characterized in terms of vaginal smears, behavioral observations and serum concentrations of estradiol-17β, progesterone and luteinizing hormone (LH) from January through June. No estrous cycles occurred in these animals between June and December. All were housed with male wolves. Two pups and 1 adult remained anestrous during this interval. One pup and 2 adults produced litters between May 4-6. Four adults exhibited endocrine changes similar to those of the pregnant animals but no litters or signs of abortion were observed. The duration of proestrus was 15.7 ± 1.6 days (X ± SEM, n = 6), of estrus 9.0 ± 1.2 days (n = 4) and of the luteal phase 63 ± 2 days (n = 6). The duration of pregnancy was between 60-65 days. The anestrous females (86 blood samples) had 6 progesterone values between 1-2 ng/ml and the remainder below 1 ng/ml. Their estradiol-17β concentrations varied between 5-20 pg/ml. Values for LH varied between 0.1-2 ng/ml, except for 1 value above 15 ng/ml for each of the 2 anestrous pups on 12 January.
The 7 estrous animals (260 samples) included 1 pup and 2 adults that delivered litters. Estradiol-17β varied between 10-20 pg/ml during proestrus, peaked at 30-70 pg/ml late in proestrus and fluctuated between 10-30 pg/ml during pregnancy or the duration of luteal activity in the nonpregnant animals. The preovulatory LH rise, 5-15 ng/ml, extended over 3 days during and immediately following the peak estradiol-17β values. An earlier elevation in LH was observed in 3 of the estrous animals. Progesterone began increasing during the LH surge and peaked 11-14 days later at 22-40 ng/ml. Progesterone concentrations greater than 3 ng/ml were maintained for 56-68 days in 6 of the 7 animals exhibiting estrus. Progesterone concentrations declined at parturition but continued to fluctuate between 0.2-3 ng/ml for 3-6 weeks.
Publication type | Article |
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Publication Subtype | Journal Article |
Title | Endocrine correlates of reproduction in the wolf. I. Serum progesterone, estradiol and LH during the estrous cycle |
Series title | Biology of Reproduction |
DOI | 10.1095/biolreprod21.5.1057 |
Volume | 21 |
Issue | 5 |
Year Published | 1979 |
Language | English |
Publisher | Society for the Study of Reproduction |
Contributing office(s) | Patuxent Wildlife Research Center |
Description | 10 p. |
First page | 1057 |
Last page | 1066 |
Google Analytic Metrics | Metrics page |