الفهرس 
Introduction and Aim of the workOnly 14 pages are availabe for public view
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Abstract
Nitric oxide (NO) is a bioregulator involved in the regulation of different body systems. It is synthesized by nitric oxide synthase (NOS) enzyme, which has three different isoforms : neuronal (n.NOS), inducible (iNOS) and endothelial (eNOS). The aim of the present research was to study the histological structure of the uterus and ovary, to perform a morphometric study of the ovarian follicles and to localise, the cells expressing iNOS enzyme in : 1) immature albino rats (experiment1). 2) adult mature cycling rats (experimentII). 3) pregnant rats (experimentIII.). A positive immunereaction for iNOS was seen in the granulosa cells of preovulatory follicles in the adult ovaries, while the reaction was negative in the hyperstimulated immature rat ovaries, suggesting a functional difference between physiological and induced ovulation, and possible role of iNOS in physiological ovulation. A positive immunereaction of iNOS was found in placenta and uterus indicating a possible role of the enzyme in the maintenance of pregnancy. The decrease in the reaction observed before and at full term may be involved in initiation of uterine contractility and consequently initiation of labour.