Anti-Müllerian Hormone and Inhibin-B Concentrations Vary Cyclically in Nonovulating Queens Within Reference Ranges Established for Determining Gonadal Status in Cats.

OBJECTIVE:To define cyclic changes in anti-Müllerian hormone (AMH), inhibin-B, and progesterone concentrations and establish statistically valid, population-based clinical reference ranges in queens.ANIMALS:Cyclic queens (fertile, n = 6; infertile, 6) from an institutional breeding colony were blood sampled longitudinally, each for over 2 months, between November 2021 and February 2022, and residual serum samples from intact (n = 205) and ovariohysterectomized (49) queens from clinical submissions were used to establish reference ranges for intact and spayed females.METHODS:AMH and inhibin-B were measured using commercially available ELISAs, progesterone was measured using an in-house ELISA, and 90% CIs were calculated from these data.RESULTS:AMH and inhibin-B fluctuated in a highly correlated, cyclic pattern in 3 queens that did not ovulate immediately, whereas AMH declined as progesterone increased, indicative of ovulation, which occurred spontaneously early in the sampling period in 3 others; statistically valid reference ranges were established in intact and ovariohysterectomized females.CLINICAL RELEVANCE:Cyclic changes in hormone profiles were defined, providing relevant context for interpreting results in cases seeking to determine gonadal status (presence or absence of gonadal tissue) on the basis of established, population-based reference ranges reported here for cats for the first time.