THE ACTION OF OVARIAN STEROIDS AND RELAXIN ON GLYCOGEN AND SOME ENZYME ACTIVITIES IN THE UTERUS OF THE HAMSTER

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Abstract
SUMMARY: Glycogen, and activities of amylophosphorylase, transglycosylase, uridine diphosphate glucose-glycogen glucosyl transferase (glycogen synthetase) and alkaline phosphatase were investigated by histochemical techniques in uteri of 44 spayed hamsters, untreated and injected with oestrogen (Oe) or progesterone (P) alone or in combination, and with or without relaxin (R). Chemical determinations of glycogen content were made for some uteri. Glycogen was visualized only in myometrial and arterial muscle fibres and migrating leucocytes. Almost none was revealed by histochemical techniques in uteri of controls and after P although chemical determinations showed moderate amounts present; this is discussed. Oe and Oe + R increased glycogen in muscle fibres of the longitudinal layer and less consistently of the circular layer. Oe + P and Oe + P + R produced greater increase in the longitudinal but no increase in the circular layers. Phosphorylase activity was visualized in myometrial and arterial muscle fibres only. Controls showed greatest activity in the circular muscle fibres. Progesterone alone produced a slight increase in the longitudinal layer. All other treatments produced strong activity in the fibres of the longitudinal layer but less consistent increase in those of the circular layer. The techniques did not differentiate between the active and the inactive forms of the enzyme and this is discussed in relation to hormonal action. The distribution of transglycosylase appeared to be similar to that of phosphorylase. Preliminary tests of glycogen synthetase revealed activity in fibres of the longitudinal layer and (in two animals given Oe) the circular layer. In untreated controls and after Oe and Oe + R, alkaline phosphatase activity was confined to epithelia, vascular endothelium and some macrophages. Activity also appeared in stromal cells and in fibroblasts of myometrial connective tissue after P, Oe + P and Oe + P + R. Myometrial muscle fibres showed no activity before or after any of the treatments. With the combinations and doses used, no certain effect of relaxin was recorded.