Sex steroids in the rat submaxillary gland during the estrus cycle

Relatively high progestagen levels were found in female rat submaxillary glands, with a maximum in the proestrus stage at 22 h and 2 minima; in proestrus between 10 and 14 h, and in estrus at 14 h. Estrogen and androgen concentrations in the gland were undetectable during most of the cycle except in the proestrus stage, when the highest level was determined at 14 h for estrogens and at 17 h for androgens.