On the nature of serum prolactin in two patients with macroprolactinemia

• Published in: Fertility and sterility Vol. 58; no. 1; pp. 78 - 87
• Main Authors: Carlson, Harold E., Markoff, Edith, Lee, David W.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.1992; Elsevier Science
• Subjects: Adult; Biological and medical sciences; Chromatography, Gel; Endocrinopathies; Female; glycosylation; Humans; hyperprolactinemia; Hyperprolactinemia - blood; Hypothalamus. Hypophysis. Epiphysis (diseases); Immunoassay; Medical sciences; Molecular Weight; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Precipitin Tests; Pregnancy - blood; Prolactin; Prolactin - analysis; Prolactin - blood; Prolactin - chemistry; Prolactin; glycosylation; hyperprolactinemia; Endocrinopathy; Case study; Human; Protein hormone; Adenohypophyseal hormone; Gel electrophoresis; Hyperprolactinemia; Hormonal investigation; Molecular weight
• ISSN: 0015-0282; 1556-5653
• DOI: 10.1016/S0015-0282(16)55140-1

To further characterize the high molecular weight (MW) forms of prolactin (PRL) present in patients with macroprolactinemia. Case reports with laboratory investigations. Academic medical centers. Two patients with macroprolactinemia. Measurements of PRL concentrations before and after chromatographic separations. The majority of serum PRL had an estimated MW of at least 669kd in the first patient and approximately 171kd in the second. During a pregnancy, a new form of PRL (MW 291kd) appeared in the first patient’s serum and persisted for at least 3 years. Immunoprecipitation and polyacrylamide gel electrophoresis under reducing and denaturing conditions revealed that the largest form of PRL (MW 669kd) was composed mostly of 25kd glycosylated PRL; intermediate forms (171kd and 291kd) were composed of roughly equal portions of 25kd glycosylated PRL and 23kd nonglycosylated PRL, whereas “little” PRL in these patients was composed primarily of 23kd nonglycosylated PRL. Injection of the first patient’s serum into rats demonstrated that the human PRL (hPRL) immunoreactivity was cleared from the serum more slowly than the PRL from sera containing predominantly little hPRL; after stimulation with thyrotropin-releasing hormone in the second patient, serum PRL concentrations decayed more slowly than observed in normal subjects. Large forms of serum PRL are at least partially glycosylated. These large forms are heterogeneous, both within and among patients. Delayed clearance may account for increased serum PRL concentrations in patients with macroprolactinemia.