Heterogeneity of gonadotropins and levels of uncombined luteinizing hormone subunits in pituitaries of cryptorchid rams.

ABSTRACT

Pituitaries were collected from intact rams and rams that had been rendered bilaterally cryptorchid by surgery to examine the effects of cryptorchidism on gonadotropin heterogeneity, levels of uncombined luteinizing hormone (LH) subunits, and the apparent molecular sizes of LH and follicle-stimulating hormone (FSH). Cryptorchid rams had higher pituitary contents of LH and FSH as well as reduced testicular weights. The levels of uncombined LH subunits, their apparent molecular weights, and the apparent molecular weights of intrapituitary LH were similar in control and cryptorchid rams. However, the apparent molecular weight of intrapituitary FSH was slightly larger in cryptorchid rams. Cryptorchidism altered the pattern of gonadotropin heterogeneity by shifting the distribution of LH isoforms towards basic components and shifting the distribution of FSH isoforms towards acidic components. Thus, it appears that the altered gonadal feedback mechanisms resulting from cryptorchidism modify the pattern of both LH and FSH heterogeneity by shifting the distribution of isoforms in opposite directions.