Human seminal plasma contains somatostatin-64.
Prosomatostatin is processed into two biologically active peptides, somatostatin (SS)-14 and SS-28. SS-14 is found in many tissues, whereas SS-28 is most prominent in the intestine. Human seminal plasma contained high concentrations (median = 3 nmol/l, range 0.6-76 nmol/l, n = 17) of SS with a higher M(r) than that of SS-28 as determined by gel chromatography. After isolation the SS immunoreactivity was identified as SS-64 based on the N-terminal amino acid sequence Leu-Ala-Glu-Leu-Leu-Ser-Glu-Pro-Asn-Gln-, and M(r) of 7242 determined by m.s. and on reactivity with two antibodies raised against SS-14. SS-64 displaced the binding of [125I-Tyr1]SS-14 to rat cerebrocortical membranes as effectively as SS-14 (IC50 = 1.6 mol/l). The concentration of SS-64 in seminal plasma from vasectomized men was significant higher (P < 0.005) than in normal men (median = 25.4 nmol/l, range 1.5-156 nmol/l, n = 21), suggesting that the synthesis of SS-64 takes place in the male accessory sex glands.
Odum
L
L
Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Denmark.
Johnsen
A H
AH
D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D007248:Infertility, Male / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D011498:Protein Precursors / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012661:Semen / Q000737:chemistry* / Q000378:metabolism; D013004:Somatostatin / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013094:Spermatozoa / Q000737:chemistry*
D010446:Peptide Fragments; D011498:Protein Precursors; C089814:prosomatostatin (29-92); D013004:Somatostatin; C028456:prosomatostatin