Endocrine correlates of reproduction in the wolf.  I. Serum progesterone, estradiol and LH during the estrous cycle

Seal, U.S.; Plotka, E.D.; Packard, J.M.; Mech, L.D.

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-17&, 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 :t 1.6 days (x SEM, n = 6), of estrus 9.0:t 1.2 days (n = 4) and of the luteal phase 63 :t 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-17& 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-17& varied between 10-20 pg/ml during proestrus, peaked at 30-70 pg/mllate 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-17& values. An earlier elevation in LH as 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.

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Article

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5222119

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Seal, U.S.; Plotka, E.D.; Packard, J.M.; Mech, L.D.

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Patuxent Wildlife Research Center

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1066

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English

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Biology of Reproduction

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1057-1066

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2287_Seal.pdf

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Endocrine correlates of reproduction in the wolf. I. Serum progesterone, estradiol and LH during the estrous cycle; 1979; Article; Journal; Biology of Reproduction; Seal, U.S.; Plotka, E.D.; Packard, J.M.; Mech, L.D.