Influence of Bilateral Cryptorchidism on Rat Pituitary Luteinizing Hormone Charge M icroheterogeneity

Publisher Website
Google Scholar
Abstract
Chromatofocusing was used to characterize the isohormones of rat luteinizing hormone (rLH) in extracts of pituitaries from intact and bilaterally cryptorchid animals. Pituitary extracts contained at least 7 isoelectric variants (isohormones) of rLH: 1 eluted in the column void volume (Isohormone, I, pI > 9.8), 5 exhibited apparant pI in the range of 9.25 to 8.97 (designated as Isohormones II-VI) and 1 bound to the column but eluted with 1.0 M NaCl (Isohormone VII, pI < 7.0). In both intact and cryptorchid rats, a large percentage of the rLH was present as Isohormone I. Furthermore, Ioshormone I was present in greater absolute and relative amounts in cryptorchid rats. All 7 rLH isohormones exhibited activity in an in vitro bioassay and the biological to immunological assay (B:I) ratios decreased with their apparent pI but were not significantly affected by cryptorchidism. When the data were expressed as the product of the amount of rLH and the B:I ratio (termed Bio-Index), Isohormone I was the predominant form of rLH in both cryptorchid and intact rats, with the Bio-Index of Isohormone I being significantly greater for crytorchid rats. These results suggest that cryptorchidism alters the pattern of rLH isohormones in the pituitary, yielding a greater percentage of the most basic rLH isohormones, which also has the highest B:I ratio. Thus, cryptorchidism significantly alters the qualitative pattern as well as the quantity of rLH in the pituitary.

This publication has 15 references indexed in Scilit: