Effect of Relaxin on Mammary Growth in the Hypophysectomized Rat
The ovarian peptide, relaxin, has long been known to modify the structures in the area of the birth canal of the pregnant animal in preparation for parturition (Hall, 1960; Hisaw, 1926; Hisaw et al,5 1944; Steinetz et al 1960). Since relaxin is found in abundance in the blood serum of many pregnant mammals, it seems plausible that the development of the mammary gland during gestation might be regulated in part at least by the presence of the hormone. Much work in delineating qualitative hormone requirements for mammary growth in hypophysectomized rats has been accomplished through the technique of whole mount observations (Cowie and Folley, 1947; Hamolsky and Sparrow, 1945; Kahn, Baker and Zannotti, 1965; Mixner, Lewis and Turner, 1940). In the past this technique was adapted to semiquantification by at best using some arbitrary numerical scale to assign each gland a grade for the extent of development (Kahn, Baker and Zanotti, 1965; Meites, 1965; Wrenn et al., 1966). Chemical DNA determination is an acceptable method for quantification in spite of the minor complication in measuring stromal as well as parenchymal tissue, and a qualitative picture of growth is not obtained. Therefore, it was concluded that the best approach to investigating the effect of relaxin on growth and differentiation of the mammary gland was to combine previously determined DNA measurements with whole mount observations, and to develop a better method of quantification for a more valid statistical analysis.
KeywordsMammary Gland SEMa Group Pregnant Animal Estradiol Benzoate Mammary Growth
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