Date of Award

Fall 1971

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Rasch, Ellen M.

Second Advisor

Piacsek, Bela E.

Third Advisor

Krishnakumaran, Alapati

Abstract

Male rat anterior pituitary (AP) glands, found to be smaller than those of females of corresponding age in terms of absolute weight and weight relative to total body weight, were studied following incubation for 2 hr. in minimal medium containing tritiated thymidine (H3TdR). Slide imprints were stained by the Feulgen reaction and subjected to autoradiography. The amount of DNA-Feulgen of individual AP nuclei from rats ranging in age from 30·150 days were determined by scanning microdensitometry and two area cytophotometry. Distributions of DNA-Feulgen values showed a significant decrease in the percentage of interclass nuclei at puberty which remained low in older animals. A corresponding pattern of labeling indices was also found. A significant increase in the level of H3TdR incorporation by individual AP nuclei was noted in animals 50 days of age and older. An arrested G-2 population of cells was absent from all glands, tetraploid nuclei being proportionate to the number of interclass nuclei and octaploid nuclei being rare. No evidence of metabolic DNA was found and analysis of probable differences in properties of the DNP component of AP cells with different template activities affecting DNA-Feulgen values was equivocal. The concept of DNA constancy is generally supported by these studies. The normal adult male rat AP is comprised of diploid cells, at least some of which maintain mitotic competence.

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