유선에서 젖의 생산은 뇌하수체 호르몬인 성장 호르몬과 프롤락틴을 포함한 여러 가지 호르몬의 조절을 받는다. 최근의 연구에 따르면 이 호르몬들 중에서 성장호르몬과 프롤락틴은 유선에서도 그 유전자 전사체가 발견된다 본 연구에서는 유선에서 발현되는 성장호르몬이 유선 특이 발현 유전자의 발현에 미치는 영향을 조사하고자 유선 특이 발현 유전자인 베타-락토글로불린(-lactoglobulin :BLG)의 프로모터를 모델 시스템으로 하여 소와 사람의 성장 호르몬이 유

Lactogenesis in mammary gland is under the control of various lactogenic hormones including hypophysial growth hormone and prolactin. Recent studies reported that such pituitary lactogenic hormones are also expressed in mammary cells as well as in pituitary. For the purpose to analyze the role of these non-pituitary hormones in mammary cells, -lactoglobulin (BLG) gene promoter was selected as a model system. The growth hormone suppressed BLG promoter activity when it was applied alone on cultured mammary HCll cells. Along with lactogenic hormones such as insulin, prolactin and glucocorticoid, however, it significantly enhanced expression of BLG promoter activity in a dosage- dependent manner. Exogenous expression of the growth hormone gene in cultured mammary cells also strongly promoted cell proliferation and BLG promoter activity. Bovine growth hormone promoter, on the contrary, did not revealed any notable activity. Above results suggest that endogenous expression of the pituitary hormone genes in mammary cells is not a regulation leakage but a physiological control. Moreover, artificial overproduction of the growth hormone in mammary gland may help increase milk production.

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