Chicken luteinizing hormone (LH) was purified from acetone-dried anterior pituitary glands by the procedure of Stockell Hartree and Cunningham (1969). In the course of purification, the fractions obtained were assayed for LH activity by the OAAD and chick testes 32P uptake assay methods, and the progress of chemical purification was assessed by analytical disc electrophoresis in polyacrylamide gel. The biological potencies of LH in the final fraction, IRC-2, were compared with those of the corresponding mammalian hormone (NIH-LH-B_8) by the induction rate of premature ovulation in the hen in addition to the two assay methods mentioned above. The fractions designated GP, CM-2, DEAE-1 and IRC-2 were confirmed to possess LH activity by the OAAD and ^32P uptake assays. The purity of chicken pituitary LH was progressed during the fractionation, however, the fraction IRC-2 was not homogeneous on disc electrophoresis. There were no significant deviations from parallelism of the log doseresponse curves for the fraction IRC-2 and NIH-LH-B_8 in both the OAAD and ^32P uptake assays. Therefere, the chicken LH was seemed to be similar in biological property to the mammalian LH, however, LH activity for mammals was less in the former than in the latter. The relative potency of chicken LH estimated by the OAAD was equivalent to 0.164 mg of NIH-LH-B_8 per mg or to 97.2 i.u. in 2nd IRP-HMG per mg. In contrast, the biological potencies of chicken LH estimated by the ^32P uptake assay and the induction rate of premature ovulation in the hen were higher as compared with those of mammalian LH, and especially the potency for inducing ovulation in. the hen was considerably higher in chicken LH. The relative potency of chicken LH estimated by the ^32P uptake assay was equivalent to 1.350 mg of NIH-LH-B_8 per mg or to 802.3 i.u. in 2nd IRP-HMG per mg. The minimal effective dose for inducing ovulation of the first follicle of a clutch in the hen was 1 μg in chicken LH and 50 μg in mammalian LH. In view of these results, it is considered that there may be a species difference in their biological activities between chicken LH and mammalian LH.
鶏LHの生物学的性質を検討するため,Stockell Hartree and Cunningham(1969)の方法に従つて下垂体前葉のアセトン乾燥粉末からLHを精製し,3種の生物検定法により哺乳類起源のLH(NIH-LH-B_8)とその効力を比較した.鶏LHを抽出精製する過程で得られた各画分について,その生物活性を卵巣アスコルビン酸減少法(OAAD法)および雛精巣^32P取込法(^32P取込法)によつて測定した結果,GP,CM-2,DEAE-1およびIRC-2画分にそれぞれLH活性が認められた.しかし最終精製画分であるIRC-2においても電気泳動的には単一成分のパターンを得ることはできなかつた.OAAD法および^32P取込法によりIRC-2画分とNIH-LH-B_8の用量反応曲線を検討した結果,これらの曲線の間には平行性が認められ,両ホルモンは生物学的に類似しているものと考えられた.しかしその効力を比較すると検定動物にラットを用いたOAAD法では,鶏LH(IRC-2)は哺乳類LHに比べかなり効力が低く,その相対効力は0.164単位であつたのに対し,雛および産卵鶏を用いた検定法では鶏LHの方が効力が高かつた.すなわち,^32P取込法では相対効力は,1.350単位であり,また排卵誘起試験ではクラッチ第1卵の排卵を誘起するための最少有効量は鶏LHで1μgであつたのに対し哺乳類LHでは50μgを必要とした.このように鶏LRは鶏を対象とした検定法とくに排卵誘起に対し極めて活性が強いことが認められた.これらの結果は鶏および哺乳類LHの生物活性において,種による反応性の差が存在することを示すものと考えられた.