It is a well known fact that Cholinesterase (ChE) is important in acetylcholine cycle.
Moreover, it has been assumed that uterine contraction might be related to ChE activity in myometrium. ChE activities of rat myometrium were observed in sexual cycle, various stages of pregnancy and puerperium by Hesterin-Miyazaki method. The effects of castration, administration of sexual hormones and contraction induced by various substances were investigated on ChE activities of non-pregnant, dregnant and puerperal myometrium.
The administrated sexual hormones were various estrogens and progestins.
Oxytocin, Methylergometrine tartrate and Acetylcholine chloride were used for inducing the contraction of rat uterus.
ChE activities of serum and placenta were simultaneously measured.
The obtained results were as follows :
1) ChE activities in myometrium decreased in estrus and after castration, and increased in diestrus.
However, ChE activities in serum were high in estrus and low in diestrus.
2) ChE activity in myometrium showed a rapid decrease up to the 14th day of pregnancy, and very slowly decreased from the 14 day through labor. Then, ChE activity was recovered to the value in non-gravid period 3 to 6 days after delivery.
ChE activity in antiplacental site of myometrium was higher than in placental site.
ChE activity in placenta was higher in late pregnancy than in mid pregnancy.
ChE activity in serum increased during pregnancy but its deviation range was rather large. Then, this activity in serum gradually decreased during puerperium and became lower on the 6th day post partum than in non-gravid period.
3) Effects of estrogens and progestins on ChE activities in pregnant myometrium were nct remarkable.
ChE activities in placenta and serum were also unchanged by estrogens and progestins.
4) ChE activities in puerperal myometrium were diminished by the administration of estradiol benzoate (1 mg or 100μg), estrone (1 mg or 100μg) or estriol (1 mg) for 6 days, but not changed by the administration of 10μg of these estrogens or 100μg of estriol.
On the other hand, ChE activities of puerperal myometrium were slightly diminished by the administration of progestins (1 mg). ChE activities of serum in puerperium became high, as in pregnancy, after the administration of 1 mg of estrogens for 6 days.
5) ChE activity was slightly low after the administration of oxytocin, but no effect of it was found in vitro. Methylergometrine tartrate and acetylcholine chloride had no remarkable effects on ChE activities in myometrium. ChE activities in serum and placenta were almost unchanged after administration of oxytocin, methylergometrine tartrate and acetylcholine chloride.
6) ChE activities were low in myometrium and placenta of uterine horn with dead fetus.

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In order to clarify the iodine metabolism of hyperthyroidism, thyroid hormone secretion (HS), thyroxine distribution space (TDS) and extrathyroidal organic iodine (EOI) were investigated with the assumption that iodine pool in the body was divided into three compartments [thyroidal organic iodine (TOI), EOI and inorganic iodine]. Subjects used in the present study were hospitalized euthyroid and hyperthyroid patients. One dose of one hundred μc of I¹³¹ was administered intravenously. At intervals there-after, I¹³¹ uptake was measured, blood was drawn for PBI¹³¹ determination. Urine and feces were collected for the assay of radioactivity.
Decay curve of the thyroid uptake following a peak uptake was seen as exponential. Let T and E be the radioactivity in terms of I¹³¹ in the thyroid and extrathyroidal organic iodine, respectively, at any time, t. Let λ_TE and λ_EI be the rate constants of secretion of thyroid hormone and of breakdown of thyroid hormone to inorganic iodine, respectively :
at T =peak, T=T₀ ; at E = peak, E E₁ and T =- T₁.
Then, T= T₁ + (T₀- T₁) e^-kt… (1)
E=T₀ -T =E₁ (1-e^-kt),
∴E₁ -E=E₁e^-kt … (2)
where K is calculated from the curve for the formula (2) by plotting on semi-logarithmic graph paper.
Here, K=λ_TE + λEI
The thyroid hormone secretion must be the same as the degradation of extrathyroidal organic iodine (extrathyroidal thyroxine) quantitatively, provided that the extrathyroidal organic iodine is constant.
Therefore, Tλ_TE = EλEI.
where, Tλ_TE thyroid hormone secretion
Eλ_EI = degradation of extrathyroidal organic iodine
Solving from both equations, Tλ_TE and Tλ_EI are calculated.
Let U and F be I¹³¹ in the urine and feces, then the thyroxine distribution space is calculated as follows :
Thyroxine distribution space (TDS)
T₀-T₁- (∑U-U₀) -∑F/Peak PBI¹³¹
Extrathyroidal organic iodine (EOI)
=TDS × (PBI × 10)
Thyroidal organic iodine (TOI)
= EOI ×T₁ /E₁
Thyroid hormone secretion (HS)
Reutilization of thyroid hormone (R) T₀/ T₀+U₀×T₁ λ_{TE -F/}/T₁ λ _TE
U₀ : Urinary I¹³¹ excretion until I¹³¹ thyroid uptake reaches peak after tracer dose
1) There was no difference in TDS and TOI between euthyroid and hyperthyroid.
2) EOI and HS were higher in hyperthyroid than in euthyroid.
3) I¹³¹ peak thyroid uptake and I¹³¹ thyroid clearance were not correlative with TOI.
4) With the days of peak PBI¹³¹ after tracer dose prolonged in hyperthyroid, HS was low, but TOT became high.
There was no correlation between EOI and the days of peak PBI¹³¹ after tracer dose.
5) In hyperthyroid peak PBI¹³¹ was most influenced by TOI, since peak PBI¹³¹ was markedly correlative with TOI and moderately with Total OI, but not with HS and EOI.
6) HS was correlative with λ_TE but not with TOI.
7) The γ values between HS and other thyroid function tests were as follows,
(PBI) ² γ= +0.69 (P<0.01)
PBI γ= +0.65 (P<0.01)
I¹³¹ peak thyroid uptake γ= +0.60 (P<0.01)
I¹³¹ thyroid clearance γ= +0.58 (P<0.01)
BMR γ= +0.46 (P<0.01)
8) In hyperthyroid TOI revealed the tendency to decrease in patients over 40 years of age,

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The author studied on the DNA and RNA metabolism in tissue culture of FL cells by means of ³H-Thymidine (³HTDN) and ³H-Uridine (³HUDN) microautoradiography. The generation time of the cells was determined by measuring the cell ccncentration at various times with a hemocytometer.
1) FL cells were exposed to prednisolone or 4-chlorotestosterone acetate, with the concentration of 10μg/cc for 24 hours, and then to ³ HTDN 0.5 μC/cc for 26 hours with steroid hormones.
A period of active synthesis of DNA (S period) and a premitotic non-synthetic period (G₂ period) were obtained from metaphase grain counts as follows :
Tg G₁ S G₂ m
Control culture 19 hrs 6.5 7.0 5.0 0.5
Pred.-treated culture 31 13.5 9.5 7.0 1.0
4Cl-TA-treated culture 24 9.7 7.5 6.0 0.8
Tg : Generation time
G₁ : a postomitotic non-synthetic period m : mitosis time
The percentage of labelled interphase nuclei measured each hour after the addition of ³HTDN should give an independent value of the S period by a mathematical treatment for exponentially multiplying cultures.
In this method, the mean value obtained for S period was 5.0 hours in the control culture, 7.3 hours in prednisolone-treated FL cells and 5.8 hours in 4-chlorotestosterone-treated FL cells.
The length of the S period was prolonged in prednisolone-treated FL cells in both methods, and prolongation of the G₁ period was more remarkable.
2) Two types of experiments on RNA metabolism were performed. In the first, FL cell monolayers were exposed to steroid hormones, 10 μg/cc for 24 hours, and then to ₃HUDN 1 μC/cc for 2 hours.
In the prednisolone-treated cultures the total uptake of radioisotope into nucleus, nucleolus and cytoplasm were gradually decreased after incubation with ³HUDN for 1 hour ; concurrently the incorporation of ³HUDN into acid insoluble compounds (mainly RNA) was depressed. But the nucleolar incorporation was active.
In the 4-chlorotestosterone acetate-treated cultures the total uptake of radioisotope was slightly decreased, but ³HUDN were incorporated into RNA alike in the control cultures.
Accumulation of ³ HUDN in the acid soluble compounds dropped in the prednisolone-treated cultures more than in the control cultures. In the latter, the accumulation of ³HUDN in the nucleus was maximum after incubation with ³IUDN for 90 minutes. On the other hand, in the former, ³ HUDN was accumulating still more.
3) In the second type of experiment, FL cells were exposed to ³HUDN 1 μC/cc for 1 hour to allow for the incorporation into cellular RNA, then a new medium containing 50 μg/cc non-radioactive uridine and 10 μg/cc prednisolone were added, and the cultures were successively incubated for 3 hours.
The incorpoation into the cytoplasm of radioisotope, that had been present in acid soluble compounds in the nucleus or in the cytoplasm prior to addition of the prednisolone, diminished to some extent in the prednisolone-treated cultures.

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