The effect of alloxan diabetes on mobilization of the liver glycogen was followed in male rats given one injection of alloxan (200mg/kg). The serum glucose showed a typical triphasic curve, reaching sustained hyperglycemia 24hr after injection. The insulin levels of serum and pancreatic tissue extract remained within normal limits for the first 24hr. The marked decrease in insulin levels from both sources was recorded on the third day. The concentration of liver glycogen, however, was already markedly decreased at the end of one hr after injection, continued at the low contents up to the 12th hr, then it temporaly rose to reach a normal value after 24hr. The outer chain length of the glycogen from one to 12hr after injection was shorter than normal and was close to the phosphorylase limit dextrin. Probably the glucose liberated by the breakdown of the outer chain of the glycogen has led to an early phase hyperglycemia. After 7 days of alloxan-induced diabates, the total hepatic glycogen as well as biochemical structure became reestablished to normal. A further discussion on interaction of alloxan and glucose is given.

View full abstract

Fifteen days after thyroidectomy, the pituitary acidophils of rats were definitely deprived of their large granules, about 350mμ in diameter each, and in due succession, they displayed the changes characterized by the features of “thyroidectomy cells” (TXcells). When these rats were given a single or three injections of thyroxine, 50mg/rat, most of TX-cells might revert to their original acidophils in a short time of 6 hr. The cytomorphological course of possible reversion of the TX-cells into acidophils was clearly demonstrated on our electron micrographs. It was learned that thyroxine exhibited a strong ability to produce large granules, 350mμ in diameter each, in TX-cells which might return to their original acidophils through the reduction of cell size probably due to contraction of ER and loss of intracisternal granules and through the re-production of the large granules in the ground matrix. If the rats, 15 days after thyroidectomy, were given dexamethasone (DM), 0.2mg/100g/day, for 14 days, most of TX-cells tended to slightly recover from their modifications due to thyroidectomy. DM had ability to produce both the small (130-150mμ in diameter) and the large (350mμ) granules in some TX-cells, but the rest of them remained unchanged and preserved a number of dilated cisternae and intracisternal granules. DM was greatly inferior to thyroxine in the ability to produce the acidophils of the large granule type (somatotrophs), while the former was superior to the latter in the ability to produce the acidophils of the small granule type. Our previous views that some TX-cells might originate from the degranulated acidophils was confirmed validly by the present observation. In conclusion, all TX-cells have not always been considered as hyperactive thyrotrophs. Mechanism of ER morphodynamics associated with vesiculation in TX-cells has been discussed with special reference to the development and reversion of TX-cells.

View full abstract

Glucagon and fluoride ion stimulated the activity of adenyl cyclase in plasma membranes prepared from the livers of rats. The maximal stimulation produced by glucagon (1μg/ml) is 5 to 15times the basal activity, and the minimum effective concentration of glucagon was 1ng/ml.
Prostaglandin E_t and insulin had no effect on the basal activity, and epinephrine showed only small stimulation of adenyl cyclase activity even at a high concentration. Insulin at varying concentrations did not inhibit the glucagon stimulated adenyl cyclase activity.
Sodium fluoride (10mM) also stimulated adenyl cyclase in plasma membranes, but the addition of fluoride ion failed to show further stimulation of adenyl cyclase activity when it was maximally stimulated by glucagon
Calcium ion, above 1×10^-4M, inhibited the glucagon stimulated adenyl cyclase activity but the fluoride stimulation was not affected even at 5×10^-3 M concentration. Trypsin digestion (10μg/ml, 5min at 37°C) or Lubrol PX treatment (0.02M, 5min) of plasma membranes resulted complete loss of the response to glucagon while the fluoride stimulation was remained.
These findings suggest that glucagon and fluoride ion are acting to stimulate a common adenyl cyclase through by different mechanisms.

View full abstract

Female Wistar rats in persistent estrus under continuous illumination (LL) restored reproductive cyclicity after being treated with sub gonad-inhibiting doses of serotonin (5-HT) or its immediate precursor 5-hydroxytryptophan (5-HTP). Intraocular injection of 5-HTP (10μg) or 5-HT creatinine sulfate (18μg) was significantly effective. Both subcutaneous dose (100μg) and single intraperitoneal dose (1.0mg/rat) of 5-HTP effectively induced diestrous smear and ovulation, with 2 to 5 days of latency, in approximately 50% of treated rats whether they had been pinealectomized or not. Among control treatments other than changing the photoperiod form LL to alternating light and dark, ether anesthesia alone interrupted the persistent estrus in nearly 50% of the “light estrous rat” of unselected stock colony. Possible mechanism underlaying restorment of estrous cycle from “light estrus” by indole amines was discussed.

View full abstract

Effects of limbic forebrain ablation on reproductive function were examined. Frontal cortex (Group A), septum (B), fornix (C), anterior limbic area (the area around anterior part of the hippocampus which located at rostral to the septal nuclei)(D), olfactory bulb (E), limbic cortex (F), and hippocampal formation (G) were ablated with suction, taking care not to damage the neighboring brain structures. Operations were performed under pentobarbital anesthesia on the day of estrus or diestrus I in 4-day cycling rats. Animals were autopsied 30 to 35 days postoperatively either on the day of proestrus or estrus. The preoptic basal hypothalamic region was intact in all examined rats.
Various degrees of septal ablation suppressed the appearance of vaginal cornification for about 10 days, although the cycle resumed eventually. However, vaginal cycles became irregular predominantly diestrous for 9/14 of the septal-ablated rats. Normal ovulation occurred in 6 of 7 rats and significant changes in serum or pituitary LH and FSH were not observed. Complete ablation of the septum, however, reduced the weight of the uterus and the amount of intraluminal fluid.
Ablation of the hippocampus induced slight increases in serum LH and FSH, and transection of the fornix increased serum LH, so that the hippocampus-fornix system seems to inhibit gonadotropin secretion. In these animals, cornified vaginal smears were absent for several days postoperatively, but the regular cycles were resumed subsequently. Normal ovulation as well as normal weights of ovaries, uterus and intraluminal fluid were observed.
Ablation of the anterior limbic area disturbed the vaginal cycle for a few days postoperatively. Marked increase in serum and pituitary LH and FSH as well as increases in ovarian, uterine and adrenal weights and greater number of ova in oviducts were observed in these animals. Thus, this area of the brain consistently appears to exert an inhibitory influence on pituitary ovarian activity.
No changes were observed in the rats with ablation of the frontal cortex, the olfactory bulb or the limbic cortex.
Therefore, limbic forebrain structures is not essential for ovulation and maitenance of the estrous cycle, but appear to exert a significant modulating influence on pituitary gonadal function.

View full abstract

With an aim to elucidate the significance of Human Placental Lactogen (HPL) during gestation, I assayed the HPL and HCG concentration in the chorionic tissue and the blood. The results as follows:
1) There was a definite correlation between the HPL concentration in the maternal serum at term and the weight of the neonates, which might lead to an idea that HPL took part in the growth of fetuses as a metabolic hormone during pregnancy.
2) It was suggested by short term incubation and the cell culture experiment that HPL concentration in the molar tissue was almost the same as or slightly higher than that of the normal chorionic villi, while the serum HPL concentration of molar patient was significantly lower than that of normal pregnant woman.
3) A simultaneous determination of HPL and HCG in serum of trophoblastic disease showed that the HPL/HCG ratio could be useful for differential diagnosis of trophoblastic disease.

View full abstract

In order to investigate a possible short feedback mechanism of insulin secretion, the effect of prior infusion of bonito insulin upon glucose-induced insulin secretion in man was studied. The increase in plasma insulin after intravenous injection of a glucose solution was analysed under prior sustaining infusion of bonito insulin at the concentration of 12mU/0.5ml/min and 6mU/0.5ml/min. These concentrations of bonito insulin were shown to have had no effect on the blood sugar levels, nor on the basal insulin levels. After the prior eight hour infusion of exogenous insulin, the increase in glucoseinduced insulin secretion was significantly smaller than that produced after infusion of saline as a control. The magnitude of the inhibition in plasma insulin elevation was more remarkable at the higher dose of insulin. The level of blood sugar after glucose injection shown no significant change.
The half-life of immunoreactive insulin in plasma was determined after prior infusion of bonito insulin or saline for three hours. There was not tendency to any difference in T 1/2 between saline treated subjects and subjects who had received the rapid injection of porcine insulin prior to the infusion of bonito insulin.

View full abstract

A highly simplified and specific radioimmunoassay (RIA) method was developed to determine plasma unconjugated estriol (E₃) during pregnancy. The antigen used for immunization of rabbits was E₃-6-0-carboxymethyp-oxime-bovine serum albumin (E₃-6-oxime-BSA), a derivative of 6-oxo-E₃. At 24 weeks after the first immunization, the antiserum diluted 1: 50, 000 showed almost no cross reaction with neutral steroids and little cross reaction with phenolic steroids except for estrone-3-sulfate (32.6%).
Plasma samples were extracted with ethyl ether and evaporated to dryness. No chromatographic purification was necessary. The dried extracts were incubated with antiserum at 24°C for 30min, then antibody-bound and free E₃ were separated with dextran coated charcoal.
The sensitivity of this method was 10pg. The intra and inter coefficients of variation were 7.8% and 11.6%. The coefficient of variation of the present method was 12.8% compared to a method using a LH-20 column chromatography for purification.
Using our simplified method, the mean plasma E₃ during pregnancy was 2.6±1.4ng/ml at 16-20 weeks and 16.4±5.0ng/ml at term.

View full abstract

L-dopa, dopamine and norepinephrine (1mg/kg) caused a marked increase in palsma growth hormone (GH) when given i.v. to trained, unanesthetized, fasting dogs. Reduction of the dose to 100μg/kg eliminated the responses. On the other hand, the relatively small dose of epinephrine (10μg/kg) could increase plasma GH level. In this case a reduction of the dose to 1μg/kg also diminished the stimulatory effect. A significant increase in plasma glucose accompanied the rise in plasma GH with dopamine, norepinephrine and epinephrine but not with 1-dopa. Furthermore, in the case of dopamine and norepinephrine a concomitant increment of plasma cortisol was also found. Alpha adrenergic blockade with phentolamine suppressed the stimulatory effect of epinephrine and 1-dopa on GH release. These results suggest that GH release stimulated by catecholamines is mediated by alpha adrenergic receptor. An attempt to inhibit dopamine beta hydroxylase with fusaric acid did not alter the stimulatory effect of 1-dopa. This result suggests an important role for dopamine in GH secretion mechanisms.

View full abstract

A successfully treated patient with myxedema coma of pituitary origin is reported. A forty-three year old woman, having a typical history of Sheehan's syndrome, was precipitated into the state of shock and coma. The coma was characterized with clinical features of myxedema coma, such as hypothermia, bradycardia and shallow respiration. The patient recovered from shock after intravenous administration of adrenocortical hormone and glucose. However, no recognizable improvement of her consciousness was obtained. She recovered from deep coma after oral administration of triiodothyronine. In addition to adequate supply of the deficient hormones, respiratory support by means of artificial respirator must have played an important role in the treatment of this patient.

View full abstract

An attempt was made to elucidate the role of an area located in the medial basal prechiasmatic area (PVA), which includes the organum vasculosum laminae terminalis of the circumventricular organ, in the regulation of gonadotropins and prolactin. Experimental animals were Wistar female rats maintained under controlled lighting. LH, FSH and prolactin in serum and pituitary were determined by means of double antibody radioimmunoassay. The results were as follows: 1) Electrical stimulation (100Hz, 0.1ms and 100μA) of the PVA through chronically implanted electrode at 12:00 on the day of proestrus increased the serum concentrations of LH and prolactin, but not FSH. 2) Rats with neural isolations of the PVA by a small J-shaped knife resumed their 4-day cycles within 5 to 7 weeks, but some of rats had abnormal uterine balooning on the day of estrus. 3) In such rats with the isolations, serum and pituitary concentrations of FSH on the day of proestrus were significantly higher than those of control rats, while on the day of estrus they were not different. 4) In these rats, the increase of LHconcentration in serum 2 weeks after bilateral ovariectomy was significantly lower than that in the ovariectomized intact rats. 5) Implantation of minute amounts of estradiol into the PVA prevented an elevation of serum concentration of LH and FSH, which occurred after bilateral ovariectomy.
From these results, it may be concluded that the PVA is involved in the mechanism to cause LH and prolactin release. Regarding FSH release, the role of the PVA was not clear in this experiment. These aspects and an electrical phenomenon, that multiple unit activity of this area showed a marked similarity to that of the arcuate nucleus during the critical period of proestrus, and that there exists a monosynaptic connection between the PVA and the arcuate nucleus, may provide an evidence that the PVA has some similarity to the arcuate nucleus in the function controlling gonadotropin and prolactin release, and furthermore that the PVA exerts its activity to release gonadotropin through the median eminence-arcuate region.

View full abstract

Effect of neurohypophyseal hormones on FFA mobilization from the adipose tissue was studied in the dehydrated rat. Despite the fact that Lys-vasopressin decreased plasma FFA concentration in the normal rat, this hormone did not produce any effect on plasma FFA in the dehydrated rat. In contrast, insulin decreased plasma FFA concentration in the rat under the same condition. Oxytocin administration did not affect on plasma FFA in the normal rat; however, it increased both plasma FFA concentration and FFA release from the parametrial adipose tissue in the female dehydrated rat. Furthermore, in vitro addition of oxytocin also stimulated FFA release from the adipose tissue of female dehydrated rat.

View full abstract