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Titolo:
BIOACTIVE AND IMMUNOREACTIVE PROLACTIN VARIANTS IN HUMAN-MILK
Autore:
ELLIS LA; PICCIANO MF;
Indirizzi:
PENN STATE UNIV,DEPT NUTR UNIVERSITY PK PA 16802 PENN STATE UNIV,DEPT NUTR UNIVERSITY PK PA 16802
Titolo Testata:
Endocrinology
fascicolo: 6, volume: 136, anno: 1995,
pagine: 2711 - 2720
SICI:
0013-7227(1995)136:6<2711:BAIPVI>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
GLYCOSYLATED HUMAN-PROLACTIN; PORCINE PROLACTIN; BIOLOGICAL-ACTIVITY; LACTATING RATS; SERUM; FORMS; PLASMA; CELLS; ACID;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
L.A. Ellis e M.F. Picciano, "BIOACTIVE AND IMMUNOREACTIVE PROLACTIN VARIANTS IN HUMAN-MILK", Endocrinology, 136(6), 1995, pp. 2711-2720

Abstract

Human milk from mothers of term (T) and preterm (PT) infants was collected during early (days 2-7), mature (2-16 weeks), or late (>16 weeks) lactation. PRL-like bioactivity (B) was measured by Nb2 cell proliferation, and PRL immunoreactivity (I) was determined by RIA. PRL activity is reported in PRL equivalents (1 PRL equivalent = 1 ng NIDDK reference material). Milk from early lactation contained significantly greater PRL-like B compared to I (T: B, 132.5 +/- 13.0; I, 83.43 +/- 12; PT: B, 195.8 +/- 56; I, 74.45 +/- 13.7). PRL-Like B and I declined as lactation progressed (T mature: B, 41.74 +/- 8.9; I, 27.19 +/- 5.5; T late: B, 17.84 +/- 5.5; I, 27.33 +/- 1.8; PT mature: B, 59.85 +/- 16; I, 45.16 +/- 4.3). Milk PRL B to I ratios were consistently greater than serum B to I ratios during early lactation (milk: T, 1.4 +/- 0.3; PT, 3.6 +/- 1.3; serum: T, 1.0 +/- 0.2; PT, 0.58 +/- 0.12). During earlylactation, high PRL-like B was widely distributed among several (n = 4-6) bioactive forms differing in molecular mass [8 to >66 kilodaltons(kDa)] in T milk, but the majority of B in PT milk was detected in two or three forms. During mature and late lactation, lower PRL-like B was associated with two or three peaks (20 to >66 kDa). A large fraction of PRL-like B (67%-84%) was associated with the phosphorylated (P-) fraction of human milk. Four immunoreactive forms (24, 30, 32, and 40 kDa) of P-PRL were identified by immunoblot analyses. Alkaline phosphatase treatment converted the 40-kDa immunoreactive P-PRL to 24-kDa PRL, increased the B of the P-fraction by 2-fold, but did not change total PRL I detected. PRL in the Concanavalin-A-retained fraction accounted for 59-69% of PRL in milk based on RIA results. No PRL-like B was detected in the Concanavalin-A-retained fraction of human milk; however,treatment of the glycosylated fraction of milk with peptide-N-glycosidase F increased thymidine incorporation by Nb2 cells 1.67-fold compared to that in controls. The results of this study show that human milkcontains considerably greater PRL-like activity than previous reportsbased on RIA detection. The appearance and regulation of multiple bioactive PRL variants in milk throughout the course of lactation may serve as a mechanism by which milk PRL influences neonatal development.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 04:50:21