Metabolism of Ribonucleic Acid during the Oestrous Cycle

Inhibition by α‐amanitin of the oestradiol‐induced increase in α‐amanitin insensitive RNA polymerase in immature rat uterus

“…Various reports have established that oestrogen-stimulated RNA is largely of ribosomal nature [3,4] . Recently, two different classes of DNAdependent RNA polymerases have been solubilized and separated from rat liver and calf thymus [5,6] : one is of nucleolar origin (enzymes A or I) and insensitive to cwamanitin [lo] , the other is mainly nucleoplasmic (enzymes B,, B,, or II) and inhibited by o-amanitin [7,IO].…”

The formation and distribution of ribosomes during hormone-induced growth and development

“…The implications of the above features in evaluating the significance of hormonal control of protein synthesis have been discussed in detail elsewhere (Tata, 1964(Tata, , 1966a Tata & Widnell (1966); the results for the effect of oestradiol on the uterus are taken from Hamilton, Widnell& Tata (1965,1967 andMoore & Hamilton (1964 (Widnell & Tata, 1966a) and muscle (Florini & Breuer, 1966), testosterone in prostate gland (Williams-Ashman et al 1964) and ecdysone in Calliphora epidermis (Sekeris, 1965). The absolute time-scale for these sequences can vary considerably according to the hormone and its target tissue.…”

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

“…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.…”

“…Previous studies dealing with such changes in a quantitative manner have been remarkably few. Thus, apart from Morgan (1963) and Hamilton, Widnell & Tata (1967) who compared the composition at two points in the cycle, i.e. oestrus and di-oestrus, the only recorded study con¬ ducted over the whole period is that of Shelesnyak & Tic (1963) who deter¬ mined quantitative changes in DNA, RNA and total protein on each day of a 4-day oestrous cycle in the rat.…”