title: The clinical utility of the protamine 1/protamine 2 ratio in sperm.
abstract: During spermiogenesis, human sperm undergo a dramatic reorganization of the chromatin in which canonical histones are replaced by two types of protamines, protamine 1 (P1) and protamine (P2). P1 and P2 are expressed approximately at a 1:1 ratio in healthy men. Alteration of this ratio is associated with male infertility. Patients with an abnormal P1/P2 ratio generally exhibit diminished semen quality, lower fertilization ability, and lower pregnancy rates when undergoing in vitro fertilization. Many studies have reported an elevated incidence of abnormal P1/P2 ratios in infertile men compared to fertile controls, and have evaluated the relationship between infertility and abnormal protamination; however, no prospective study has investigated the normal range of the P1/P2 ratio in men from the general population. Here, we report a P1/P2 reference range of 0.54 to 1.43 in a fertile, normozoospermic population. This rather wide normal range of P1/P2 led us to the conclusion that abnormal protamination is more likely indicative of other perturbations during spermatogenesis than the underlying mechanism to cause infertility. Alternatively, protamine expression may act as a checkpoint mechanism and thus be indirectly related to semen quality.
authors: Andrology and IVF Laboratories, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA.
authors: Laszlo
authors: L
authors: Nanassy
authors: Lihua
authors: L
authors: Liu
authors: Jeanine
authors: J
authors: Griffin
authors: Douglas T
authors: DT
authors: Carrell
mesh_terms: D000328:Adult; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007248:Infertility, Male / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011479:Protamines / Q000032:analysis / Q000378:metabolism*; D013094:Spermatozoa / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002843:Chromatin; C082073:PRM1 protein, human; D011479:Protamines; C068621:protamine 2