Influence of estrogens on vascular transudation and mucus production in the rabbit endocervix

The manner in which estrogens mediate cyclical changes in the viscoelastic properties and volume of cervical mucus is unclear. To identify the response to estrogens of each of the major mucus components (mucin[s], soluble proteins, and small electrolytes and water), the authors quantitated their accumulation rates before and during estrogen stimulation in the rabbit. Circulating radiolabeled markers (35S-sulfate and 131I-albumin) were used to monitor the incorporation of small and large molecular weight intravascular substances into the cervical mucus. The accumulation rate of mucins was unaffected by exogenous estrogen administration, despite significant increases in mucus volume. This increase in mucus volume was attributed to a significantly increased transudation of water and small electrolytes increasing mucus hydration as early as the first 2 hours of estrogen administration. Water, small electrolytes, and soluble proteins significantly increased during the third and fourth hours of estrogen administration, not only when compared with the unstimulated basal levels, but also when compared with the levels found during the first 2 hours of estrogen administration. No significant change occurred in mucin production, while significant changes occurred in the accumulation of proteins and small electrolytes, whether estrogen was given initially or terminally in the experiment protocol.