La. Vanginkel et al., HETEROGENEITY OF HUMAN LUTEINIZING-HORMONE IN PITUITARY-TUMOR HOMOGENATES AND CELL INCUBATES, Journal of endocrinological investigation, 18(4), 1995, pp. 258-264
Incubation media of pituitary cells and homogenates of pituitary tumor
s were studied by isoelectric focusing followed by radioimmunoassay. A
lmost all LH-immunoreactive components detected had been observed in e
arlier studies on highly purified preparations. In one pituitary tumor
homogenate, intact LH (LH(i)) was detected. The majority of LH(i)-com
ponents present in this tumor were relatively acidic (LH Type I) compo
nents. The corresponding beta-subunit population was in agreement with
the one earlier observed for Type I LH. In all other tumor homogenate
s only alpha- and beta-subunits could be detected. In incubation media
of pituitary cells from patients with-no known endocrine disease nor
a pituitary tumor highly acidic populations of alpha-subunits were det
ected. In only one of the incubation media significant amounts of LH(i
) and free beta-subunits were observed. In an incubation medium of a T
SH-producing pituitary tumor significant amounts of intact LH, free al
pha- and beta-subunits were detected. The cell contents of this tumor
contained components with lower pI-values than the medium. In general
a good correlation is observed between the population of LH-components
in material from individual identifiable pituitary glands and in high
ly purified preparations from large numbers of anonymous pituitary gla
nds.