passages.id: split_4_test_2809_passage
passages.type: progene_text
passages.text: Germ cells primarily utilized the 1st ATG codon ( + 1 ) and contained major proteins of 61 / 56 kDa , whereas Leydig cells utilized preferentially the 2nd ATG codon ( + 343 ) with expression of 48 / 43 kDa species .