Ovine Luteinizing Hormone: Isoforms in the Pituitary DGring the Follicular and Luteal Phases

I Pituitaries were collected from late Relative to follicular and luteal phase ewes, follicular phase (n = 51, mid-luteal phase (n = 51, anestrous ewes had lower percentages of isoforms and anestrous ewes In = 4) to assess changes in D and E as well as higher percentages of isoforms intrapituitary LH heterogeneity a t selected G, H, J and K. Isoform F, the predominant reproductive states. After homogenization, an alimolecular form of LH, constituted a similar perquot of each pituitary extract was desalted by flow centage in all treatment groups (P > .05). Thus, the dialysis against water and chromatofocused on a distribution of intrapituitary LH among its isopH 10.5 to 4.0 gradient. Concentrations of LH in forms did not change significantly between the pituitary extracts and chromatofocusing fractions mid-luteal and follicular phases of the estrous were determined by RIA. The LH in pituitary cycle, but higher percentages of the weakly basic extracts resolved into 13 isoforms during chroand acidic forms of LH were present during matofocusing, which were coded with letters beanestrus. These observations suggest that inginning with the most basic isoform. Follicular and trapituitary LH heterogeneity changes minimally mid-luteal phase ewes exhibited similar distributhroughout the estrous cycle of ewes during the tions of intrapituitary LH among its isoforms. breeding season.