下垂体甲状腺系の膵ラ氏島に及ぼす形態学的変化について

抄録

Recently, the influences of the hormones from hypophysis-thyroid system on glucose metabolism has been studied. On the other hand, in the clinical observation, it has been frequently observed that diabetes mellitus or a simple symptom of urinary sugar is accompanied with hyperthyrodism. However, morphological influence of the hormones of this system on the pancreatic islets is not well known. In order to clarify the influence of the hormones of this system on the islets and to investigate the relationships between the histological findings and their functions, the author carried out the following series of experiments.
Materials and Methods
In this series of experiments, rats were used mainly, and sometimes rabbits were used.
The materials were colected under the conditions as described below.
These animals were divided into five groups as follows :
a) Thyradin (Powder of dried thyroid) administered group : Dosages were 20 mg/100g/day for rats and 200 mg/head/day for rabbits.
b) TSH administered group : Dosage for rats was 10 JSU/100g/day.
c) Growth hormone administered group : Dosage was 10 mg/head/day for rabbits.
d) Thyroidectomized group.
e) Hypophysectomized group.
In order to carry out the morphological studies and planimetric measurements of pancreatic islets on the above mentioned animals, the following methods were used :
a) Gomori's Chromealum-Hematoxylin-Phloxin and Aldehyde-Fuchsin dying-method, b) dying of zinc, c) dying of SS-SH groups, d) measurements of the area of Langerhans' islets, e) beta/alpha cell ratio, and f) nuclear volumes of alpha and beta cells.
Results a) Thyradin administered group :
After the administration of 200 mg each day for seven days, slight decrease in the quantity of beta granula, margination of beta granula, decrease in the amount of zinc, and enlargement of nuclei were observed in Langerhans' islets. These results seemed to show that the release of insulin still exceeded its production, although the production was accelerated much more than that in normal state. Alph cells were not changed, apparently.
After the administration for thirty days, degenerative change of beta cells, remark-able decrease of beta granula, condensation of nuclei, decrease in the amount of zinc, and decrease in the amount of SS-SH groups were found. These findings support the suggestion that there is an exhaustion of beta cells after the course of hyperfunction.
For alpha cells, decrease of beta/alpha ratio and slight enlargement of the cells were observed.
In the case of rabbits which were administered thyradin for fifty two fifty six days, there was no difference in the findings from those in rats.
The hormones of the thyroid seemed to accelerate the function of Langerhans' islets and decelerate it later.
b) TSH administered group :
After the administration of TSH for seven days, decrease in the quantity of beta granula, decrease in the amount of zinc, decrease in the amount of SS-SH groups were observed. These results seemed to show the acceleration of the release of insulin. No enlargement of nuclei and nucleoli would show the absence of the acceleration in the production of insulin.
After the administration of TSH for thirty days, decrease in the quantity of beta granula and remarkable decrease in the amount of zinc seemed to show the acceleration of release of insulin. And also increase and decrease of SS-SH groups seemed to show the acceleration of biological production.
This acceleration of the function of beta cells seems to be a secondary effect of the influence of TSH on glucose metabolism through thyroid.
c) Growth hormone administered group :
After the administration of growth hormone of 10 mg/day for fifty two-fifty six days, decrease in the quantity of granula and zinc of beta cells, and the tendency to increase in the dimensions of Langerhans' islets were found. There was no change of nucleoli.