Collagen Content of the Nonpregnant Rat Uterus as Related to the Functional Responses to Estrogen and Progesterone

Quantitative Changes in Uterine Nucleic Acids During the Oestrous Cycle in Rats

“…3), it is clear that a total increase in nitrogen and general growth occurs, reaching a maximum some time after the ratio of RNA/DNA has reached a maximum. These patterns are very similar to those found previously by Morgan (1963) and Smith & Kaltreider (1963) for total uterine wet weight, total nitrogen and total dry matter/uterus, but differ considerably from those reported by Shelesnyak & Tic (1963). These last authors found that the uterine content of DNA, RNA, protein and total dry matter were highest at pro-oestrus and decreased steadily to a low point at mid-oestrus.…”

“…This change in RNA was also found when calculated/ unit of DNA and thus represents an increased synthesis of RNA/cell during pro-oestrus and oestrus. Hamilton et al (1967) showed that, in the Oestrus' rat, the increased RNA was found entirely in the cytoplasm and is presumably ribosomal (Moore & Hamilton, 1964 (Morgan, 1963;Smith & Kaltreider, 1963;Harkness, Harkness & Morallie, 1957). Even so, when the total uterine content is considered (Text- fig.…”

The effect of oestrogen on uterine plasticity in late pregnant rats

“…How¬ ever, there is no evidence that the uterine tissue of ovariectomized rats treated with progesterone alone produces more prostaglandins than that of rats treated with progesterone + oestrogen (Ramwell, Leovey & Sintetos, 1977 (Harkness & Harkness, 1954), and the combined treat¬ ment of progesterone and oestrogen produces a rapid accumulation of collagen in the uteri of ovariectomized rats (Morgan, 1963;Smith & Kaltreider, 1963). The administration of pro¬ gesterone or oestrogen alone had no distinct effect on the collagen content in the whole uterus, but histological studies showed that oestrogen is necessary for the deposition and maintenance of collagenous bundles in the rat endometrium (Fainstat, 1962).…”

Resorption of Endometrial Collagen in Oophorectomized Rats

“…Biochemical studies demonstrated [Smith and Kaltreider, 1963] that 53% of the total uterine content of collagen is removed during the first 4 days after oophorectomy, a steady state being reached when colla gen falls to about 66% of the amount formed during estrus. Our morphological findings are thus supported by that report, since we have observed the greatest number of collagenous microfibrils in fibroblasts occur ring at the 2nd day after oophorectomy.…”

“…The uterine content and the turnover of collagen have been demonstrated to be diminished in oophorec tomized rats [Harkness et al, 1956;Smith and Kaltreider 1963]; accordingly, the inhibitory action of estradiol on collagen breakdown has been documented [Woessner and Ryan, 1980], If direct, ultrastructural examination of collagen removal after oophorectomy were undertaken, then the cell type primarily responsible should be detected. Furthermore, since biochemical studies have demon strated a hormonal role regulating this phenomenon, then estradiol or progesterone treatment of oophorec tomized rats should interfere with uterine collagen removal.…”