Figure 1.

Ovulation failure in Gnrhr^E90K homozygotes results in persistent estrus and low levels of progesterone. A to E, Hematoxylin-eosin–stained ovarian sections. Corpora lutea (CL) (white asterisks) were abundant in heterozygous controls (A, B, and D), but absent in Gnrhr^E90K homozygotes (C and E). A to C, scale bar = 100μm; D and E, scale bar = 250 µm. F, Average number of CL per ovary (± SEM). G to I, Steroid hormone levels. J to M, Real-time polymerase chain reaction gene expression levels (± SEM) in the ovary. *P less than .05, *** P less than .005, t test. K90/+, Gnrhr^E90K heterozygotes; K90/K90, Gnrhr^E90K homozygotes.