We have examined the ability of 17beta-estradiol (E2) to induce development of mammary cancers in the female ACI rat. Continuous treatment with E2, delivered through release from s.c. Silastic tubing implants containing 27.5 mg crystalline hormone, resulted in rapid development of palpable mammary tumors in ovary-intact ACI rats. In a population of 21 E2-treated rats, palpable tumors were first...

The short and long forms of prolactin receptor (PRL-R) mRNA have been detected in the female rat brain. The present study aimed to investigate: (1) if the PRL-R mRNA is expressed in the male rat brain; (2) if expression levels in the female brain vary during the estrous cycle. All animals were sacrificed between 12:00 and 14:00 h. Radioactive RNase protection assay was used to measure mRNA leve...

THE action of hormonic substances on the smaller experimental animals is usually assessed by killing the animal and examining its organs shortly after treatment. The present paper deals with a study of the effects of testosterone propionate injections on the subsequent life of the female rat. An earlier paper (Groome, 1939, which see for references) describes the immediate anatomical effects of...

Cross-reactivities among tumor-associated antigens of rat mammary fibroadenomas and among these fribroadenomas and a rat mammary carcinoma were investigated by in vitro techniques. Lymphocytes from five female W/Fu rats bearing mam mary fibroadenomas were found to share a common reactivity against fibroadenoma target cells, as demon strated by lymphocyte cytotoxicity tests on iododeoxyuridine-1...

Variations in parental care predict the age of puberty, sexual activity in adolescence and the age at first pregnancy in humans. These findings parallel descriptions of maternal effects on phenotypic variation in reproductive function in other species. Despite the prevalence of such reports, little is known about potential biological mechanisms and this especially true for effects on female rep...

Clivorine, a naturally occurring pyrrolizidine alkaloid, causes liver toxicity via its metabolic activation to generate toxic metabolite (pyrrolic ester). Female Sprague-Dawley (SD) rats are reported to be less susceptible to clivorine intoxication than male SD rats. However, the biochemical mechanism causing such gender difference is largely unknown. The present study investigated hepatic micr...