Progesterone Augments the Venoconstrictor Effect of Ruscus without Altering Adrenergic Reactivity

Chronic administration of oestrogen and/or progesterone does not affect adrenergic neurotransmission or contractions initiated by sympathomimetic amines in the cutaneous venous smooth muscle of the dog. However, contractions initiated by the venotropic Ruscus-extract are enhanced following chronic exposure to progesterone, an affect that can be reversed by oestrogen. The contractions are mediated by an adrenergic and non-adrenergic component. The adrenergic component is enhanced by progesterone and decreased by oestrogen; the non-adrenergic component is most prominent when the serum-levels of the female steroid hormones are low.