Relationships Among Plasma Zinc,Plasma Prolactin,Milk Transfer,and Milk Zinc in Lactating Women

Abstract

The objective was to analyze interrelationships among plasma zinc (PZ), plasma prolactin (PRL), milk transfer, and milk zinc from a longitudinal study of lactating women with a range of zinc intakes. Sixteen of 26 women received a 15 mg/d zinc supplement, resulting in a significant increase in total zinc intake compared with nonsupplemented participants (P < .001). No significant differences in key variables were observed between the zinc-supplemented and non—zinc-supplemented women; data were thus combined. An inverse trend between PRL and PZ was observed at 0.5 (r = −.36, P = .08) and 7 months (r = −.38, P = .06). Correlations between PRL at 0.5 months and at 3, 5, and 7 months were significant (r > .50, P < .01). PRL concentrations and milk transfer were positively correlated at 5 (r = .67, P < .001) and 7 months (r = .53, P < .01), consistent with PRL role in lactation maintenance. Studies including zinc-deficient lactating women are required to clarify the interrelationships between zinc status and PRL secretion. J Hum Lact. 23(2): 179-183.

Keywords

plasma zinc plasma prolactin zinc supplementation milk transfer milk zinc human lactation

Get full access to this article

View all access options for this article.

References

Lorenson MY , Patel T. , Liu JW , Walker AM Prolactin (PRL) is a zinc-binding protein. I. Zinc interactions with monomeric PRL and divalent cation protection of intragranular PRL cysteine thiols. Endocrinology. 1996;137:809-816.

Brandao-Neto J. , Madureira G. , Mendonca BB , Bloise W. , Castro AV Endocrine interaction between zinc and prolactin. An interpretative review. Biol Trace Elem Res. 1995;49:139-149.

LaBella F. , Dular R. , Vivian S. , Queen G. Pituitary hormone releasing or inhibiting activity of metal ions present in hypothalamic extracts. Biochem Biophys Res Commun. 1973;52:786-791.

Login IS , Thorner MO , MacLeod RM. Zinc may have a physiological role in regulating pituitary prolactin secretion. Neuroendocrinology. 1983;37:317-320.

Chowanadisai W. , Kelleher SL , Lonnerdal B. Maternal zinc deficiency raises plasma prolactin levels in lactating rats. J Nutr. 2004;134: 1314-1319.

Caticha O. , Norato DY , Tambascia MA , Santana A. , Stephanou A. , Sarlis NJ Total body zinc depletion and its relationship to the development of hyperprolactinemia in chronic renal insufficiency. J Endocrinol Invest. 1996;19:441-448.

Mahajan SK , Hamburger RJ , Flamenbaum W. , Prasad AS , McDonald FD Effect of zinc supplementation on hyperprolactinaemia in uraemic men. Lancet. 1985;2:750-751.

Brandao Neto J. , de Mendonca BB , Shuhama T. , et al. Zinc: an inhibitor of prolactin (PRL) secretion in humans. Horm Metab Res. 1989;21: 203-206.

Travaglini P. , Moriondo P. , Togni E. , et al. Effect of oral zinc administration on prolactin and thymulin circulating levels in patients with chronic renal failure. J Clin Endocrinol Metab. 1989;68:186-190.

10.

Koppelman MC , Greenwood V. , Sohn J. , Deuster P. Zinc does not acutely suppress prolactin in normal or hyperprolactinemic women. J Clin Endocrinol Metab. 1989;68:215-218.

11.

Krebs NF , Reidinger CJ , Hartley S. , Robertson AD , Hambidge KM Zinc supplementation during lactation: effects on maternal status and milk zinc concentrations. Am J Clin Nutr. 1995;61:1030-1036.

12.

Krebs NF , Reidinger CJ , Robertson AD , Brenner M. Bone mineral density changes during lactation: maternal, dietary, and biochemical correlates. Am J Clin Nutr. 1997;65:1738-1746.

13.

Krebs NF , Reidinger CJ , Robertson AD , Hambidge KM Growth and intakes of energy and zinc in infants fed human milk. J Pediatr. 1994; 124:32-39.

14.

Food and Nutrition Board & Institute of Medicine. Dietary Reference Intakes for Individuals, Elements . Washington, DC: National Academy of Science; 2004.

15.

Ingram JC , Woolridge MW , Greenwood RJ , McGrath L. Maternal predictors of early breast milk transfer. Acta Paediatr. 1999;88:493-499.

16.

McMahon RJ , Cousins RJ Mammalian zinc transporters. J Nutr. 1998; 128:667-670.

17.

Kelleher SL , Lonnerdal B. Zinc transporters in the rat mammary gland respond to marginal zinc and vitamin A intakes during lactation. J Nutr. 2002;132:3280-3285.

18.

Kelleher SL , Lonnerdal B. Zn transporter levels and localization change throughout lactation in rat mammary gland and are regulated by Zn in mammary cells. J Nutr. 2003;133:3378-3385.

19.

Gaither LA , Eide DJ Functional expression of the human hZIP2 zinc transporter. J Biol Chem. 2000;275:5560-5564.

20.

Kelleher SL , Lonnerdal B. Zip3 plays a major role in zinc uptake into mammary epithelial cells and is regulated by prolactin. Am J Physiol Cell Physiol. 2005;288:C1042-C1047.

21.

Aono T. , Shioji T. , Shoda T. , Kurachi K. The initiation of human lactation and prolactin response to suckling. J Clin Endocrinol Metab. 1977;44:1101-1106.

22.

Kauppila A. , Kivinen S. , Ylikorkala O. Metoclopramide increases prolactin release and milk secretion in puerperium without stimulating the secretion of thyrotropin and thyroid hormones. J Clin Endocrinol Metab. 1981;52:436-439.

23.

Flint DJ , Gardner M. Evidence that growth hormone stimulates milk synthesis by direct action on the mammary gland and that prolactin exerts effects on milk secretion by maintenance of mammary deoxyribonucleic acid content and tight junction status. Endocrinology. 1994;135: 1119-1124.

24.

Neville MC , McFadden TB , Forsyth I. Hormonal regulation of mammary differentiation and milk secretion. J Mammary Gland Biol Neoplasia. 2002;7:49-66.