The alkaline phosphatase is one of the enzymes widely distributed in the body. However the reports of the presence of the enzyme in the pancreas and salivary gland are rare. The physiologic function of the enzyme is still obscure although some investigators have suggested its possible role to be absorption of some material from the gastrointestinal tract and it was observed that the enzyme is mainly membrane-bound in histochemical studies(Gomori, 1941; Mathies et, al., 1949; Clark, 1961).
The effects of the sex hormones have been well investigated in the human endometrium, with evidence of the enhancement of alkaline phosphatase activity due to estrogen stimulation(Levine, 1963). Atkinson and Elftman(1946) reported a marked increased of alkaline phosphatase in the uterine glands and epithelium of ovariectomized mice following estrogen injection, while progesterone and androgen had no effect.
A recent report by Foster(1971) suggested that the ovulation time could be determined by measurement of the salivary alkaline phosphatase using the tape-method.
The present investigation is undertaken to find the effects of the sex hormones following oophorectomy upon distribution of alkaline phosphatase in the salivary gland as well as in the pancreas.
Materials and Methods
Female adult rabbits with an average weight of 1.5kg were used for the experiments. These sere divided into 5 groups according to treatment as follows:
Group Ⅰ: Normal control
Group Ⅱ: Oophorectomized, bilateral
Group Ⅲ: Estrogen injection after bilateral oophorectomy
Group Ⅳ: Progesterone injection after bilateral oophorectomy
Group Ⅴ: Pregnant
The each group was subdivided into 3 groups at various intervals, except for group Ⅴ which had 2 subgroups. In group Ⅲ, 20,000 I.U. of estrogen in a dose of 1ml. was given i.m. daily, while 50gm. of progesterone in a dose of 1ml. was given
in group Ⅳ.
Necropsy specimens were obtained from the salivary gland and pancreas in each group and blood was also taken from the abdominal aorta at the same. The frozen sections were made by means of cryostat. The demonstration of the tissue alkaline phosphatase in the salivary gland and pancreas was performed by the modified Gomori's method. The measurement of serum alkaline phosphatase was done by the Fiske-SubbaRow method.
Results and Discussion
The effects of sex hormones on the salivary gland and pancreas were examined in bilaterally ovariectomized rabbits by histochemical methods.
In the salivary glands of the normal control group, alkaline phosphatase activity showed mild to moderate increase in the acini while it was relatively high in the capillaries. However, there was no activity in the secretory ducts.
Meanwhile, in the normal control pancreas, moderate to high alkaline phosphatase activity was noticed within the lumens of the acini whereas only a trace of activity was seen in the interlobular secretory ducts.
Gilateral oophorectomy caused a slight decrease in the alkaline phosphatase. In the estrogen-treated rabbits the alkaline phosphatase activity of the salivary gland was more marked compared with that of the pancreas. There were no changes in
the degree of enzyme activity in relation to time lapse. Both in the pregnant and the progesterone-treated rabbits, the distribution of the alkaline phosphatase activity was similar to that in the untreated normal controls. The levels of the serum alkaline phosphatase shoed no significant differences in each group.
In summary, it was shown clearly in the present study that the injection of estrogen in the ovariectomized rabbits was followed by a marked increase in alkaline phosphatase in the salivary gland with a less marked increase in the pancreas.