Comparison of Luteal Function in Pseudopregnant and Pregnant Hamsters

The functional status of corpora lutea (cl), as inferred by their weight and progesterone content, was evaluated in pregnant and pseudopregnant golden hamsters. In addition, the duration of pseudopregnancy was determined in intact hamsters and in animals made pseudopregnant by separating the uterus from the ovary. Pseudopregnancy was induced in (1) intact hamsters by mating them to vasectomized males, (2) hamsters in which utero-tubal connections were interrupted either bilaterally or unilaterally, (3) animals which were hysterectomized at least 8 days before mating. In all cases, the day spermatozoa were found in the vaginal smear was designated Day 1 of pregnancy or pseudopregnancy. cl were dissected from the ovaries and weighed; progesterone was determined by the competitive binding method (Neill, Johansson, Datta & Knobil, 1967). The end-point for the termination of pseudopregnancy was the reappearance of the conspicuous postovulatory vaginal discharge. The data in Table 1 show that