Pituitary Isografts Research Articles

Induction of Mammary Cancer in Agent-Free Mice Bearing Pituitary Isografts Correlated With Inherited Hormonal Mechanisms<xref ref-type="fn" rid="FN1">2</xref>

Induction of Mammary Cancer in Agent-Free Mice Bearing Pituitary Isografts Correlated With Inherited Hormonal Mechanisms<xref ref-type="fn" rid="FN1">2</xref>

Corticosterone in mouse adrenal in relation to sex and heterotopic pituitary isografting.

In two populations of mice, one inbred (C, Bag albino), the other hybrid, adrenal ‘corticosterone’ levels determined at time of peak physiologic secretion differed consistently between the two sexes. The female glands, heavier than those of males, had the higher content and concentration of ‘corticosterone.’ In female C and D8 (Dilute Brown, subline 8) mice, adrenal ‘corticosterone’ content is further elevated during a period from about 64 to about 180 days after pituitary isografting; i.e. many months prior to the appearance of breast cancers, induced or enhanced in these stocks by the heterotopic pituitary.

Activity rhythm and breast cancer in pituitary-isografted C and D8 mice; effect of hypothalamus.

SummaryA light-dark synchronized activity rhythm persists in pituitary-isografted C mice. The adrenal cycle probably persists in mice with a significantly altered estrous cycle (1,2). Multiple pituitary isografts are associated with adenocarcinomata and adenoacanthomata in virgin female mice of the D8 and C stocks. The carcinogenic effect of the pituitary isografts is statistically significant and not a result of trauma. Number of implants as well as presence or absence of mammary tumor agent also are significant variables, but neither variable is critical to carcinogenesis from pituitary isografts, under the conditions studied. Insertion of the hypothalamus at the time of pituitary implantation delays mammary carcinogenesis by mechanisms as yet unknown.