ABSTRACT
The succeeding ovulatory phase is characterized by a sharp surge in plasma gonadotropin concentrations, taking an average of 14 hours to occur. Plasma estrogen levels fall from their peak at the same time LH and FSH are on their ovulatory upswing. Plasma androgen concentrations decline, but a significant elevation in progesterone is initiated. Typically, a single follicle in one of the ovaries will reach maturity in a given cycle, with ovulation often occurring in the alternate ovary during the following cycle. Following ovulation, luteal output of progesterone is significant, and a second rise in 17-estradiol occurs. Progesterone is thermoginic, and tends to shunt blood toward the internal organs causing a slight rise in the basal body temperature for about 1-2 days following ovulation.
