The influence of suckling on the hypothalamic and pituitary secretion of immunoreactive alpha-melanocyte stimulating hormone.
The effect of suckling on the secretion of alpha-melanocyte stimulating hormone (alpha-MSH) from the hypothalamus and pituitary was determined by a specific radioimmunoassay. There was an increase in the neurointermediate lobe (NIL) content of alpha-MSH 1 h after the onset of suckling. The values were restored to control levels within 3 h. The anterior lobe content of alpha-MSH was not affected by suckling. Plasma alpha-MSH levels were also unaffected by suckling, indicating that suckling probably affects the synthesis of NIL alpha-MSH, and not its release. Suckling lowered the alpha-MSH content in the mediobasal hypothalamus of lactating rats, and had no effect on the median eminence content of this peptide. In vitro, hypothalami from lactating rats released more alpha-MSH than hypothalami of random cycling females under basal, and stimulated (56 mM potassium) conditions. These results suggest that hypothalamic alpha-MSH may play a role in mediating some of the hormonal changes occurring during lactation.
D000818:Animals; D005260:Female; D007031:Hypothalamus / Q000032:analysis*; D007033:Hypothalamus, Middle / Q000032:analysis; D007774:Lactation / Q000378:metabolism*; D008473:Median Eminence / Q000032:analysis; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis* / Q000097:blood; D010903:Pituitary Gland, Anterior / Q000032:analysis*; D011247:Pregnancy; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D009074:Melanocyte-Stimulating Hormones