Serum prolactin in patients with Laron-type dwarfism: effect of insulin-like growth factor I.
Prolactin (PRL) secretion was studied in Laron-type dwarfism (LTD) patients (8 children and 9 adults) in basal condition, after acute insulin-like growth factor (IGF-I) or TRH injections and during 2 months of daily IGF-I treatment. Basal PRL was repeatedly higher (12.6 +/- 1.6 micrograms/l) than that in control subjects (7.6 +/- 1.2 micrograms/l, p < 0.05). Acute IGF-I injection caused an immediate slight decrease in serum PRL and growth hormone (GH), followed by a progressive rise to mean peak levels of 33.3 +/- 4.5 micrograms/l again parallel to serum hGH which rose to 86 +/- 20 micrograms/l--a response to the IGF-I-induced hypoglycemia. Intravenous TRH in LTD children induced a marked response in serum PRL, similar to that registered in estrogenized adult females. Serum PRL did not show consistent changes during chronic IGF-I treatment. It is suggested that the higher-than-normal PRL levels and release in LTD patients are due to a drift phenomenon of the mammosomatotropes which produce large amounts of hGH.
Silbergeld
A
A
Institute of Pediatric and Adolescent Endocrinology, Children's Medical Center, Petah Tikva, Israel.
Klinger
B
B
Schwartz
H
H
Laron
Z
Z
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004392:Dwarfism / Q000097:blood*; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D011388:Prolactin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone
D001786:Blood Glucose; D013973:Thyrotropin-Releasing Hormone; D007334:Insulin-Like Growth Factor I; D011388:Prolactin; D013006:Growth Hormone