Degree Type

Dissertation

Date of Award

1988

Degree Name

Doctor of Philosophy

Department

Animal Science

First Advisor

Stephen P. Ford

Abstract

Both the luteotrophic effects of estrogen and the relative lack of luteolytic effects of PGF[subscript]2[alpha] in cycling pigs might be interpreted to suggest that luteal function in this species differs markedly from that in other domestic animals. These aspects of porcine luteal function were studied to establish the basis for this premise. Additionally, the cellular effects of PGF[subscript]2[alpha] and the activation of protein kinase C on luteal cells was investigated using dispersed ovine luteal preparations. Dispersion of ovine CL results in luteal cell preparations suitable for cell culture experiments not obtainable by similar dispersion techniques;Experiment I. Estradiol-17[beta] containing implants were placed unilaterally inside 3 individual CL of one ovary on day 11 of the estrous cycle to evaluate the direct luteal effects of this hormone in pigs following recovery of ovaries on day 19. At the highest dose of estradiol, but not in other groups, CL were maintained bilaterally with an additional significant increase in luteal weight and progesterone content in those CL receiving estradiol implants over all others;Experiment II. Estrogen implants were placed unilaterally inside all CL on an ovary on day 11 of the cycle to evaluate the functional effects of estrogen exposure for 8 days on progesterone and PGF[subscript]2[alpha] concentrations in utero-ovarian venous (UOV) blood. Estrogen induced uniform, bilateral luteal maintenance, and markedly suppressed UOV PGF[subscript]2[alpha] concentration. Luteal function appeared to decline to day 15 then recovered in estrogen-treated gilts to preinjection levels on day 19 as indicated by UOV progesterone;Experiment III. An ovary was removed from gilts on day 8 of the estrous cycle, prior to PGF[subscript]2[alpha] or vehicle administration on day 9, and the final ovary was recovered on day 12. Progesterone was monitored in systemic blood and luteal weight and content of progesterone, protein and DNA were determined in luteal tissue before and after PGF[subscript]2[alpha] exposure;Experiment IV. The effects and interaction between PGF[subscript]2[alpha], phorbol ester and calcium ionophore were investigated in day 9 dispersed oveine luteal cells by monitoring progesterone in culture medium. Phorbol ester, calcium ionophore and PGF[subscript]2[alpha] were all inhibitory at higher concentrations but none were additive in their effects. (Abstract shortened with permission of author.)

DOI

https://doi.org/10.31274/rtd-180813-12156

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Alan James Conley

Language

en

Proquest ID

AAI8909138

File Format

application/pdf

File Size

175 pages

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